Keywords: Soft Robot Materials and Design
Abstract: Voxel-based robots are aggregations of soft and simple building blocks that have been extensively evolved and simulated to perform various tasks, like walking, jumping or swimming. However, real-life voxel-based robots are rather scarce because of their challenging design and assembly. With the current materials and assembling methods,

the interfaces between the soft multi-material voxels are prone to failure. This work proposes to make voxels out of reversible Diels-Alder polymers, which are available in a broad range of mechanical properties. By doing so, the covalent bonds at the multi-material interface ensure strong chemical connections, while allowing for reconfiguration. A first voxel-based gripper is thus robustly assembled, then disassembled, using its pieces (voxels) for reassembling another robot, i.e., a voxel-based walking robot. This reconfigurable property allows iterative validation of the simulated voxel-based robots and fine-tuning of the simulations parameters in a sustainable and economical way. Both physical voxel-based robots show similar behaviors as their simulations with root-mean-square errors down to 10.4%.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design, Soft Robot Applications
Abstract: Origami is a practical approach for developing soft robots and deployable structures. If the folding and stiffness are actively adjustable, we can program the motion of the resulting origami structure. Here, we propose an entirely soft inflatable origami actuator with variable stiffness and multimodal deformation. The programmable inflatable origami consists of a prismatic chamber based on the Kresling pattern with miniature fluidic channels at the mountain folds. Applying a vacuum to the central chamber provides the main actuation force, while the selective inflation of the fluidic channels controls the motion and changes the stiffness. We formulated a geometric description for the origami module to optimize the design parameters. Then, we fabricated the origami actuators from elastomeric rubber using a multistep single-material fabrication technique. Finally, we characterized the axial contraction and rotation angle and demonstrated variable stiffness and omnidirectional bending. Our work imbues origami actuators with embodied behavior presenting an integrated versatile soft robotic building block applicable to manipulation and locomotion scenarios.

Keywords: Grippers and Other End-Effectors, Compliant Joint/Mechanism, Soft Robot Applications
Abstract: Soft grippers have demonstrated significant improvements in grasping in unstructured environments and grasping delicate objects. However, there are limitations preventing more widespread real-world use, from low holding force, high control complexity in diverse object sets, and challenges picking in clutter and more. We present a soft adaptive suction cup design---featuring a morphing granular jamming cup augmented by a suction-based `Xeno-Tongue'---which can pick and handle diverse objects under a variety of environmental constraints, or lack of. The gripper combines soft suction with an in-built pulling mechanism, i.e., the tongue provides active pulling for automatic suction cup shape adaptation to objects independent of the surrounding environment. We characterise and predict the grasping performance on a series of benchmarking surfaces. Additionally, grasping real-world objects, in clutter and a simulated harvesting environment, using an unmodified control strategy demonstrates adaptability and agility for rapid application in agriculture and other industries.

Keywords: Medical Robots and Systems, Soft Robot Applications, Soft Robot Materials and Design
Abstract: The development of green batteries has implications for many fields including sustainable robotics and edible electronics. Here we present GelBat, a biodegradable, digestible and rechargeable battery constructed from gelatin and activated carbon. The device utilises the water splitting reaction to produce a simple, sustainable Bacon fuel cell which can produce an output voltage of over 1V for 10 minutes, depending on the load resistance, with 10 minutes of charging and whose only byproduct is water. Electrochemical impedance spectroscopy, cyclic voltammetry and self discharge tests are carried out to characterize the behaviour of the battery. The system does not lose any efficiency with repeated recharging cycles and can be completely dissolved in a simulated gastric fluid within 20 minutes. The simplicity of this design combined with the bioresorbable materials demonstrates the potential of this work to help advance robotic research towards more sustainable untethered autonomous systems and edible robots.

Keywords: Soft Robot Materials and Design, Soft Sensors and Actuators, Micro/Nano Robots
Abstract: Energy sustainability poses a great challenge in miniaturised soft robotics. Light, as renewable and clean energy, is promising to power, actuate and control such robots. However, efficient, high-speed and high-power actuators operating on light-provided power are still in their infancy and subject to intensive research. Here, we demonstrate photo-thermal bimorph actuators based on polydimethylsiloxane (PDMS), graphene (G), and muscovite mica. The PDMS/G/Mica photo-thermal actuator converts light efficiently to displacement and force. Under illumination, the PDMS/G/Mica actuators achieve a large curvature change of 0.76 mm^{-1} at moderate light intensities of 170 mW/cm^2, beyond that of most photo-thermal actuators reported in the literature so far. The actuators are further integrated into bio-inspired, photo-responsive soft robotic structures such as flower petals and inchworms to demonstrate their suitability for various future applications.

Keywords: Soft Robot Materials and Design, Soft Sensors and Actuators, Haptics and Haptic Interfaces
Abstract: Vibration is ubiquitous as a mode of haptic communication, and is used widely in handheld devices to convey events and notifications to users. The miniaturization of electromechanical actuators that are used to generate these vibrations has enabled designers to embed such actuators in wearable devices, conveying vibration at the wrist and other locations on the body. However, the rigid housings of these actuators mean that such wearables cannot be fully soft and compliant at the interface with the user. Fluidic textile-based wearables offer an alternative mechanism for haptic feedback in a fabric-like form factor. To our knowledge, fluidically driven vibrotactile feedback has not been demonstrated in a wearable device without the use of valves, which can only enable low-frequency vibration cues and detract from wearability due to their rigid structure. We introduce a soft vibrotactile wearable, made of textile and elastomer, capable of rendering high-frequency vibration. We describe our design and fabrication methods and the mechanism of vibration, which is realized by controlling inlet pressure and harnessing a mechanical hysteresis. We demonstrate that the frequency and amplitude of vibration produced by our device can be varied based on changes in the input pressure, with 0.3 to 1.4 bar producing vibrations that range between 160 and 260 Hz at 13 to 38 g, the acceleration due to gravity. Our design allows for controllable vibrotactile feedback that is comparable in frequency and outperforms in amplitude relative to electromechanical actuators, yet has the compliance and conformity of fully soft wearable devices.

Keywords: Soft Sensors and Actuators, Biologically-Inspired Robots, Grippers and Other End-Effectors
Abstract: Autonomous sensor deployment in unstructured natural forests utilizing aerial vehicles is a promising alternative to manual sensor placement by humans, yet retrieval of deployed sensors still remains a challenge. A biodegradable deployment system is therefore crucial to avoid any harmful e-waste in the target environment. However, challenges arise in the choice of materials, design and manufacturing methods to develop such transient, lightweight grippers with an appropriate response time, high deformation, and versatility for diverse shapes of tree branches for sensor deployment. In this work, we propose a hygroscopically actuated, lightweight and biodegradable gripper as a practical solution for the above challenge. Our gripper utilizes dehydration of a bio-polymer to achieve sufficient deformation requiring up to 3 W to coil around a tree branch with multiple turns. The design achieves a gripping force of up to 1.3 N, which is sufficient to deploy lightweight environmental sensors on a tree. The gripper can also exhibit fast actuation capability to complete a coiling turn in less than 120 s, which enables a typical aerial vehicle to deploy tens of sensors in a single charging cycle. Furthermore, this work presents a proof-of-concept of the proposed hygroscopic gripper demonstrating the potential of aerial sensor deployment for future forest monitoring tasks. Such systems could be used to collect data with high spatial and temporal resolution while ensuring low pollution of the environment.

Keywords: Soft Robot Applications, Soft Robot Materials and Design, Grippers and Other End-Effectors
Abstract: Industrial automation calls for precise tasks with cycle times reduced to the minimum. At the same time, when handling delicate products such as fruits and vegetables, accelerations must be kept low to keep interaction forces under a certain threshold to avoid damage. This trade-off hinders the penetration of automation in many relevant application fields. This paper investigates using soft technology to solve this challenge. We propose the FinFix gripper, a non-anthropomorphic soft gripper capable of handling delicate objects at high acceleration using a contact-reactive grasping approach. This gripper has two entirely passive sensorized fingers that establish contact and two active fingers that are actuated pneumatically through a rigid mechanism allowing for rapid closure. We provide exhaustive experimental validation by connecting the gripper to a delta robot. The system can reliably execute pick-and-place cycles in ~1s when the distance between the pick and the place locations is 400mm, resulting in a peak speed of ~10m/s. None of the fragile objects used during the experiments showed any damage. The only information needed is a rough estimation of the object's position to be grasped and a contact event to trigger the reflex. The test results show that the gripper can hold fragile objects during lateral accelerations of 10g.

Keywords: Soft Robot Materials and Design, Additive Manufacturing, Grippers and Other End-Effectors
Abstract: Pneumatic soft actuators are widely used in various applications. Recent years, pneumatic origami actuators were studied intensively because of the advantages of high energy efficiency, large deformation, and rich deformation patterns. However, the fabrication of pneumatic driven origami-based soft robot is a challenging task, in which air leakage can result in disfunction of the robots. In this paper, we propose an alterative approach to fabricate pneumatic origami structure using an industrial 3D printer which is capable of 3D printing liquid silicone rubber (LSR). We took the Kresling pattern as an example and explored the essential parameters of printer setting. We directly printed the 3D folded structure (origami-inspired structure) instead of 2D folding to simplify the fabrication process. In addition, to maximize the design freedom, we propose modularized design of the origami-inspired actuator. After fabricating the basic modules, robots can be freely assembled according to different applications. Finite element simulations and experiments were conducted to characterize the basic modules in terms of deformation, rotation angle, and generated force. Finally, a robotic gripper were developed using the basic modules and grasping experiments were conducted to prove the concept of modularization.

Keywords: Grippers and Other End-Effectors, Grasping, Soft Robot Applications
Abstract: In soft grippers, deformable materials are crucial for safety and adaptability. However, materials alone are not enough to ensure a successful grip. Soft grippers are generally designed to exploit precision or power grasp but still show limited versatility in handling objects whose characteristics are widely different. This paper presents a soft gripper with a monolithic pneumatic artificial muscle (M-PAM) design. The monolithic approach prevents failure from delamination while it improves lifetime. Concurrently, adjustable finger distance and a foam interface improve stability during grasping. The resulting structure exerts a maximum force of 1.95 N and reaches a bending angle of 78.27° corresponding to a positive pressure of 18 kPa. Furthermore, an optimized geometry increases the contact area and grasping strength. A soft gripper integrating two M-PAMs is demonstrated grasping fruit with dimensions ranging from 0.5 to 65 mm.

Keywords: Grasping, Soft Robot Materials and Design, Compliant Joint/Mechanism
Abstract: Pin array grippers with many slidable pins arranged in parallel can adapt to complex object shapes. However, in conventional methods that move the pins only in specific directions, the conditions for successful grasping are limited by the shape, position, and orientation of the target object. In this study, we propose a balloon pin array gripper capable of inflating flexible balloons in the radial direction of each pin. This method makes the soft wrapping of objects possible from multiple directions in a two-step shape adaptation: pin array sliding and balloon expansion. A design method for combining balloons with a pin array, including an air supply system, was devised. Experiments and tests with the prototype demonstrated the validity of the concept.

Keywords: Computational Geometry, Hydraulic/Pneumatic Actuators, Modeling, Control, and Learning for Soft Robots
Abstract: McKibben artificial muscles are an important example of braided, tubular structures made of many interwoven helical fibers. Their highly non-linear response is very robust and reproducible, making them particularly suitable for applications in Soft Robotics. The rich behavior of McKibben actuators has been studied either through minimal geometric models or through complex Finite Elements Method (FEM) simulations. To obtain a simpler yet accurate model for McKibben actuators, we develop a simplified framework entirely based on the geometry of the virtual envelope surface defined by the fibers of the mesh. In the axisymmetric cases studied here, the problem boils down to solving for a single scalar field of one scalar variable. We validate our model by solving contractor and extensor muscle configurations and comparing them against experimental and numerical results from the literature, achieving good agreement at a significantly lower computational cost. Simulations reveal that loads are sustained mostly by the braided mesh, whereas the inner chamber stores most of the external work as elastic energy. This phenomenon explains why simplified formulas for force-pressure relationship may be quite effective in predicting the behavior of McKibben actuators.

Keywords: Grasping, Grippers and Other End-Effectors, Industrial Robots
Abstract: Soft grippers show adaptability and flexibility in grasping irregularly shaped and fragile objects, in which actuating method is the key technology to drive the soft grippers. As an actuation method achieved through pneumatic or hydraulic systems, the particle jamming effect shows stiffness variation and is widely applied to soft grippers. However, soft grippers are expected to be applied in large scales, and at these scales it is challenging to achieve the jamming effect in pneumatic or hydraulic systems. In this paper, a novel active particle jamming method is proposed for the design of a particle jamming-based soft gripper. The proposed method uses active hydrogel particles instead of vacuum pressure to achieve the jamming effect. Additionally, the bending behaviors are implemented based on the jamming effect and actuator design. The numerical model is carried out to explore the actuator behaviors, and a brief experiment case is conducted to verify the feasibility. The results indicated that the proposed actuator achieves the functionality of bending actions by swelling the hydrogel particles. The bending performance is enhanced by lowering the trigging temperature and increasing the thickness of the strain-limit layer. Additionally, there is a transition state from bending to curling when increasing the layer of particles.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design, Biologically-Inspired Robots
Abstract: A Variable Stiffness Actuator (VSA) can vary the stiffness of a robot joint. Robots which use rigid links but soft joints like VSAs are known as articulated soft robots. The articulated soft robot arm in this paper uses an agonist/antagonist VSA setup with composite tendons made out of a soft material on the inside and an ideally non-elastic material on the outside. The outer material gradually aligns with the direction of the load, and compresses the inner soft material during extension. This provides a cheap and compact tendon that can be made to exhibit suitable spring characteristics for a VSA. The focus of the work presented here is to optimize the manufacturing process of these soft tendons through methodological tuning of parameters and the usage of off-the-shelf materials. The filament, outer sleeve and pulley configurations are modeled, and tensile testing used to provide data on the effect of different design parameters on the tendon properties. Soft tendons with an outer mesh sleeve that are easy to manufacture are implemented in a proof of concept experiment on the robot arm elbow joint. The results show that variable stiffness can be achieved with the proposed design but that the available outer sleeve is too flexible resulting in only a small range of stiffness levels. Several directions for improvement are identified.

Keywords: Biologically-Inspired Robots, Soft Sensors and Actuators, Soft Robot Materials and Design
Abstract: Lateral undulation is essential for limbless animals to interact with their environment and facilitate their travelling wave motion. The earthworm uses bending of its body and tip to reduce environmental compaction, anchor itself, and create space for burrowing. In this study, we designed and developed a burrowing soft robot for peristaltic locomotion by observing the lateral undulation behavior at the earthworm's anterior region. To achieve this, we utilized two different soft actuator modules. The tip modules performed lateral undulation and elongation, while the rest of the actuator modules facilitated axial elongation and passive contraction. We characterized the actuator's performance in terms of lateral bending angle, elongation displacement, and penetration force when the tip module interacted with granular media for three different cases: static, tip undulation, and tip elongation. Based on the findings of this characterization, we conducted locomotion experiments with three different gait patterns: tip undulation, tip undulation with elongation, and tip elongation, to evaluate the penetration force and behavior of the peristaltic soft robot when moving in granular media. The results show that tip undulation enhances the locomotory performance of the peristaltic soft robot.

Keywords: Biologically-Inspired Robots, Grippers and Other End-Effectors, Soft Robot Applications
Abstract: Soft robotics is a novel disruptor that has attracted the interest of robotic developers, allowing them to leverage the use of soft materials and compliant mechanisms to interact better with soft objects. This paper presents the development and characterization of a vacuum-driven soft-bending actuator that utilizes an origami skeletal structure. The proposed actuator comprises a skeleton from an origami folded thin polyvinyl chloride (PVC) sheet and a pouch made from thermoplastic polyurethane (TPU) coated polyester fabric. The developed actuator is experimentally evaluated to characterize its bending angle, blocked force, and holding force performance. The actuator has a maximum bending angle of 840, a maximum lifting force of 7 N, and a maximum tip blocking force of 1.8 N at 40 kPa (abs). The developed soft bending actuator is integrated into a three-finger gripper to evaluate its gripping performance. The developed gripper successfully handled several irregularly shaped daily objects and soft food items. The gripper could withstand a pulling force of up to 18.35 N.

Keywords: Robot Companions, Soft Robot Materials and Design, Additive Manufacturing
Abstract: Soft robotics is an exciting new field of robotics that replaces stiff components with soft materials and actuators, making it an ideal way to design robotic companions. Robotic companions are becoming common and can be helpful in treating patients with dementia by providing comfort, a sense of companionship, and promoting a healthier lifestyle. This work presents a soft robotic companion that uses acupuncture and acupressure principles to facilitate relaxation to its users. Inspired by the hedgehog, the robot provides a unique interaction mode and uses a functional quill array to stimulate pressure points.

Keywords: Multifingered Hands, Soft Robot Materials and Design, Grasping
Abstract: While parallel grippers and multi-fingered robotic hands are well developed and commonly used in structured settings, it remains a challenge in robotics to design a highly articulated robotic hand that can be comparable to human hands to handle various daily manipulation and grasping tasks. Dexterity usually requires more actuators but also leads to a more sophisticated mechanism design and is more expensive to fabricate and maintain. Soft materials are able to provide compliance and safety when interacting with the physical world but are hard to model. This work presents a hybrid bio-inspired robotic hand that combines soft matters and rigid elements. Sensing is integrated into the rigid bodies resulting in a simple way for pose estimation with high sensitivity. The proposed hand is in a modular structure allowing for rapid fabrication and programming. The fabrication process is carefully designed so that a full hand can be made with low-cost materials and assembled in an efficient manner. We demonstrate the dexterity of the hand by successfully performing human grasp types.

Keywords: Biologically-Inspired Robots, Underactuated Robots, Soft Robot Applications
Abstract: Manta rays are unique animals that exhibit complex motion behavior, given their rigid bodies and flexible fins. During turning maneuvers, these animals can hold their fins in asymmetric positions while flapping to achieve a smaller turning radius and faster-turning speed. This collective behavior can be challenging to attain using conventional soft robots or actuators. Local bistability can be leveraged to mimic this behavior by inducing spatially distributed prestress in thin, fin-like surfaces that reshape into 3D, stable configurations without the need of continuous actuation. We present a pneumatically actuated manta ray-inspired soft robot concept with multiple stable states which approximate the ray's asymmetric strokes and stroke frequency. The fins are actuated by an array of inflatable bistable and metastable dome-shaped units that allow us to independently deflect sections of the fin to achieve a desired position. We tune our robot's geometry by performing a numerical parameter sweep over different geometrical configurations of the patterned dome structure. Our approach offers a new route for imposing various target 3D deflected positions of morphing surfaces with minimal actuation or feedback control by utilizing multistability.

Keywords: Soft Robot Materials and Design, Hydraulic/Pneumatic Actuators, Compliant Joint/Mechanism
Abstract: In recent years, the need for a variable stiffness mechanism to control the stiffness of a robot structure has been observed in soft robotics. There are various stiffness methods, and various linear mechanisms have been proposed to achieve extension, contraction, bending, and joint rotation of each method. However, to the best of our knowledge, no linear mechanism with variable stiffness in the two axes of extension, contraction, and joint rotation. This is because, in the conventional variable stiffness method, the air tube of the pneumatic actuator encased in the structure cannot maintain the desired shape under pressure due to wrinkling and buckling that occur when the air tube is deformed in response to the extension, contraction, and joint rotation of the structure. Therefore, it was necessary to develop a new method of encasing the air tube. The mechanism proposed in this study is to bend the flat tube that serves as the flow path into an S-shape to achieve extension, contraction and joint rotation, and to apply internal pressure to make the stiffness variable. Using a prototype based on this original principle, we confirmed the performance of switching stiffness in conjunction with extension, contraction and joint rotation. Experiments measuring the holding force during extension, contraction and the holding torque during joint rotation revealed that the holding force and holding torque were highly dependent on the pressure-receiving area between the mechanism and the S-shaped folded flat tube. In the future, we aim to apply this mechanism to a posture holding assist.

Keywords: Rehabilitation Robotics, Soft Robot Applications, Wearable Robots
Abstract: Nonsurgical treatment of Dropped Head Syndrome (DHS) incurs the use of collar-type orthoses that immobilize the neck and cause discomfort and sores under the chin. Articulated orthoses have the potential to support the head posture while allowing partial mobility of the neck and reduced discomfort and sores. This work presents the design, modeling, development, and characterization of a novel multi-degree-of-freedom elastic mechanism designed for neck support. This new type of elastic mechanism allows the bending of the head in the sagittal and coronal planes, and head rotations in the transverse plane. From these articulate movements, the mechanism generates moments that restore the head and neck to the upright posture, thus compensating for the muscle weakness caused by DHS. The experimental results show adherence to the empirical characterization of the elastic mechanism under flexion to the model-based calculations. A neck support orthosis prototype based on the proposed mechanism is presented, which enables the three before-mentioned head motions of a healthy participant, according to the results of preliminary tests.

Keywords: Soft Robot Materials and Design
Abstract: Thin, planar sheets can be programmed to morph into complex shapes through stretching and out-of-plane bending, with applicability to shape-shifting soft robots. One way to make a morphing sheet is to use variable stiffness fibers that can modulate their tensile stiffness attached to the surface of a volumetrically expanding sheet. Adjusting local stiffnesses via tensile fiber jamming during sheet expansion allows control of the local shape tensor. However, finding the fiber placements and jamming policies to achieve a set of desired shapes is a non-trivial inverse design problem. We present an additive inverse design framework using an evolutionary algorithm to find optimal jamming fiber patterns to match multiple target shapes. We demonstrate the utility of our optimization pipeline with two input curvature pairs: 1) cylinder and sphere curvatures and 2) simple saddle and monkey saddle curvatures. Our method is able to find a diverse set of sufficient solutions in both cases. By incorporating hardware constraints into our optimization pipeline, we further explore the transfer of evolved solutions from simulation to reality.

Keywords: Rehabilitation Robotics, Soft Robot Materials and Design, Wearable Robots
Abstract: This study proposes a soft wearable robot that supports scapular adduction and abduction to rehabilitate respiratory diseases. For the elderly, the decrease in the range of thorax movement due to aging increases the risk of respiratory diseases. Although adduction and abduction exercise of the scapula effectively improves the movement range of the respiratory muscles around the thorax, it is difficult for the elderly owing to reduced voluntary upper-arm mobility, and hence a physiotherapist's support is required. The proposed robot has a simple mechanism with a small degree of freedom that supports the elderly in stretching their thorax on their own at home.　We first describe the design concept of the proposed soft robot with a shoulder brace with elastic components to constrain shoulder movement.　Then, we conduct a pilot study to determine appropriate design parameters based on a therapist's kinematic analysis of the glenohumeral joint during the stretching. The evaluation experiment with eight healthy participants to validate the supporting function of the system is described.　Hence, we confirm that the proposed system can provide scapular adduction and abduction movement similar to what physiotherapists provide.

Keywords: Soft Sensors and Actuators, Soft Robot Applications, Soft Robot Materials and Design
Abstract: Soft fabric-based structures like fabric based soft actuators, grippers and manipulators are gaining in popularity due to their ability to generate large payloads while being lightweight, extremely compliant, low cost and fully collapsible. It is however challenging to achieve full pose sensing of fabric based soft fingers without compromising on these advantageous properties. This paper provides an overview of the work done on soft fabric based inflatable finger design, actuation and sensorisation at Advanced Robotics at Queen Mary (ARQ). Experimental analysis is performed to examine additional features such as bending control and eversion (growing from the tip) in fabric based fingers for grasping applications. Using these fingers, two types of grasp force are then measured for a two-fingered gripper: envelope grasping and pinch grasping. In addition to force measurement, this paper also puts forward the concept of their sensorisation using soft optical-based waveguide sensors and shape estimation using image processing.

Keywords: Soft Robot Materials and Design, Biologically-Inspired Robots, Soft Robot Applications
Abstract: Deployable and reconfigurable structures use shape-changing designs to transform between different forms and create usable structures, often from small initial packages. While these structures create reliable transformations, the exact shapes must be defined at design and manufacturing time. However, many applications in unstructured environments would benefit from deployable structures that can adjust to the circumstances of the application on demand. To address this need for autonomous behavior, we propose deployable robotic structures, combining soft shape-changing robots with passive and permanent stiffening. The specific implementation in this paper uses chemical curing capable of creating stiffness change at arbitrary locations along a soft growing robot without impeding the function of the robot or requiring a continuous supply of energy to maintain its rigidity. In structural testing, the application of this method is able to drastically increase load resistances axially by an average of 64~N and transversely by an average of 2.18 Nm. Finally, two demonstrations are performed, which show how this combination of soft growing robot and permanent stiffening can increase the structure's carrying capacity and expand the robot's navigational capabilities, showing the potential of deployable robotic structures.

Keywords: Biologically-Inspired Robots, Soft Robot Materials and Design, Grasping
Abstract: Spider monkeys (genus Ateles) have a prehensile tail that functions as a flexible, multipurpose fifth limb, enabling them to navigate complex terrains, grasp objects of various sizes, and swing between supports. Inspired by the spider monkey tail, we present a life size hybrid soft-rigid continuum robot designed to imitate the function of the tail. Our planar design has a rigid skeleton with soft elements at its joints that achieve decreasing stiffness along its length. Five manually-operated wires along this central structure control the motion of the tail to form a variety of possible shapes in the 2D plane. Our design also includes a skin-like silicone and fabric tail pad that moves with the tip of the tail and assists with object grasping. We quantify the force required to pull various objects out of the robot's grasp and demonstrate that this force increases with the object diameter and the number of edges in a polygonal object. We demonstrate the robot's ability to grasp, move, and release objects of various diameters, as well as to navigate around obstacles, and to retrieve an object after passing under a narrow passageway.

Keywords: Soft Sensors and Actuators, Force and Tactile Sensing, Soft Robot Materials and Design
Abstract: Flexible robots have advantages over rigid robots in their ability to conform physically to their environment and to form a wide variety of shapes. Sensing the force applied by or to flexible robots is useful for both navigation and manipulation tasks, but it is challenging due to the need for the sensors to withstand the robots' shape change without encumbering their functionality. Also, for robots with long or large bodies, the number of sensors required to cover the entire surface area of the robot body can be prohibitive due to high cost and complexity. We present a novel soft air pocket force sensor that is highly flexible, lightweight, relatively inexpensive, and easily scalable to various sizes. Our sensor produces a pressure response that is linear with the applied force. We present results of experimental testing of how uncontrollable factors (contact location and contact area) and controllable factors (initial pressure, thickness, size, and number of interior seals) affect the change in internal pressure when an external force is applied. We also present strategies to mitigate uncontrollable factors and use controllable factors to achieve high sensitivity. We demonstrate our sensor applied to a vine robot---a soft inflatable robot that ``grows" from the tip via eversion---and we show that the robot can successfully grow and steer towards objects with which it senses contact.

Keywords: Soft Robot Materials and Design, Grippers and Other End-Effectors, Soft Robot Applications
Abstract: We test grip strength and shock absorption properties of various granular material in granular jamming robotic components. The granular material comprises a range of natural, manufactured, and 3D printed material encompassing a wide range of shapes, sizes, and Shore hardness. Two main experiments are considered, both representing compelling use cases for granular jamming in soft robotics. The first experiment measures grip strength (retention force measured in Newtons) when we fill a latex balloon with the chosen grain type and use it as a granular jamming gripper to pick up a range of test objects. The second experiment measures shock absorption properties recorded by an Inertial Measurement Unit which is suspended in an envelope of granular material and dropped. Our results highlight a range of shape, size and softness effects, including that grain deformability is a key determinant of grip strength, and interestingly, that larger grain sizes in 3D printed grains create better shock absorbing materials. The data set is publicly available at https://doi.org/10.25919/tgck-2r85.

Keywords: Soft Sensors and Actuators, Perception for Grasping and Manipulation, Grippers and Other End-Effectors
Abstract: Soft grippers are very popular for complex gripping tasks, as they can easily grip objects of different shapes. Also, usually they cannot damage gripped objects because of their inherent softness. Additionally, in contrast to rigid grippers no or only very little control effort is needed for the gripping process. However, also for soft grippers sensor feedback can help to improve the gripping process and thus expand the range of applications. Thereby, besides gripping force measurements, especially curvature measurements are of interest to reconstruct the deformation of the gripper.

In this contribution, a soft three-finger-gripper with integrated optical shape sensor, based on curvature sensors, is presented. The shape sensor allows to control the gripping process and check if an object is gripped correctly.

Keywords: Soft Sensors and Actuators, Grasping, Hydraulic/Pneumatic Actuators
Abstract: In soft robotics, variable stiffness is typically employed to solve the trade-off between compliance and the ability to exert high forces. However, modulating the stiffness of a soft actuator can also provide control over its deformation and enhance its adaptability. This latter concept has not been thoroughly investigated in literature and this work aims at demonstrating variable kinematics enabled by the integration of variable stiffness modules into the structure of a soft finger. We have augmented a segmented pneumatic bending actuator with two-layer jamming modules integrated into its proximal and distal sections and proposed an actuation strategy designed through finite element modeling to control its shape in terms of angle of attack and grasping radius. The presented soft finger exhibited a grasping width in the range of about 40 mm to 75 mm while simultaneously keeping the angle of attack around 90°. Different activations of the two-layer jamming modules also produced an alteration of the forces exerted by the finger which were characterized in terms of blocking and grasping force for different configurations. The results show an interesting and less explored use of variable stiffness, relevant for the development of adaptive soft grippers and manipulators. Moreover, the proposed concept and control strategy is independent of the actuation technologies used to produce finger bending.

Keywords: Additive Manufacturing, Soft Robot Materials and Design, Hydraulic/Pneumatic Actuators
Abstract: With the rise of new applications for soft actuators, more advanced methods of fabrication are being used to obtain the desired complex internal structures. Due to their accuracy, affordability, and ability to create airtight structures, Stereolithography (SLA) and Digital Light Processing (DLP) printing are becoming increasingly common for manufacturing these soft fluidic actuators (SFAs). The manufacturing of SFAs using these printing methods requires various post-processing steps to ensure that the final result exhibits the desired behavior when pressurized. However, the required steps are often poorly documented and mainly focus on cleaning the exterior of an SLA/DLP printed part. In this paper, we provide a methodology to clean the complex internal structures of SLA/DLP printed SFAs. This methodology comes in the form of a peristaltic pump used to cycle the cleaning liquid through the internal geometry of the SFA, and a clear cleaning procedure. We compare our cleaning procedure to the standard procedure, showing the effectiveness of the proposed method.

Keywords: Soft Robot Materials and Design, Additive Manufacturing, Hydraulic/Pneumatic Actuators
Abstract: This paper presents a method for manufacturing a soft pneumatic linear actuator. The linear actuator is based on a deformable chamber reinforced by a cylindrical auxetic structure. The objective of this work is to create a hermetic silicone chamber inside the auxetic structure previously machined in PVC. The manufacturing process is based on 3D silicone printing using an anthropomorphic robotic arm. The proposed strategy increases the versatility of the process compared to overmolding strategies, especially in regard to the dimensions of the actuator. In this paper we present an experimental setup integrating a robotic arm, the system for the registration of the different elements and the control of the print head trajectories. The actuator has been designed, built and implemented, allowing us to evaluate its performances and life span.

Keywords: Soft Robot Materials and Design, Soft Sensors and Actuators
Abstract: Intelligent materials offer new avenues when de- signing sustainable robotics as they allow for the creation of dynamic constructs which react autonomously to changes in the environment, such as humidity. Here we present a novel humidity actuator that exploits the unique property of deliquescent salts to allow for the spontaneous rehydration of hydrogels in ambient environments. By soaking a 2% w/v alginate, 3% w/v Agar composite in 1M calcium chloride, an intelligent humidity-driven actuator was developed. The hydrogel was able to gain 73.8±7.1% of its weight from a dehydrated state in just 6 hours through water absorption from ambient air. Using this novel formulation, linear and bilayer bending actuators were constructed. In addition to this, a biodegradable deliquescence-actuated artificial flower was demonstrated, highlighting this material’s potential to act as an intelligent humidity actuator for the construction of environmentally-reactive biomimetic sustainable robotics.

Keywords: Soft Sensors and Actuators, Tendon/Wire Mechanism, Soft Robot Materials and Design
Abstract: This paper presents a tunable stiffness actuator with a soft-rigid combined layer jamming mechanism. The tunable stiffness actuator is aimed to be integrated into an exosuit to prevent ankle sprain and avoid or mitigate the development of chronic ankle instability. The main purpose of the soft-rigid layer jamming mechanism is to produce large stiffness with a small volume and achieve a linear stiffness characteristic. To this end, the actuator is designed to include rigid retainer pieces within the soft silicone layers, and each soft-rigid layer is jammed to induce stiffness changes. To validate the stiffness characteristics of the proposed soft-rigid actuator, a series of experiments were performed and stiffness changes were investigated for varying jamming states from unjammed to fully jammed states. Increasing the number of jamming layer effectively increased the actuator stiffness, which was consistent with expected results from the analytical model. Soft-rigid actuator’s stiffness at the fully jammed state was 212.1% and 123.1% higher than the unjammed state for one-side and both sides anchored conditions, respectively. Compared to the soft actuator without the rigid retainer, the soft-rigid actuator exhibited a more linear characteristic (Pearson correlation coefficient = 0.990 and 0.997 for one-side and both sides anchored conditions, respectively). Moreover, the soft-rigid actuator achieved significantly higher stiffness than the soft actuator in all jamming states (at least 41.3% increase in each jamming state). The results suggest a potential use of the tunable stiffness actuator to develop a soft ankle exosuit with highly variable but linear stiffness characteristics.

Keywords: Soft Robot Materials and Design, Compliant Joint/Mechanism, Soft Robot Applications
Abstract: Soft pneumatic actuator with strain-limiting layers has played an important role in soft robotics in the last decades. However, limited by their pre-designed and permanent strain-limiting layers, their motion pattern is usually single. Here, we proposed a soft pneumatic actuator with multiple motion patterns based on length-tuning strain-limiting layers. We integrated 4 cable-based strain-limiting layers into a 3D printed soft pneumatic actuator. A cable locking system is proposed to lock the cables as strain-limiting layers. The system is actuated by a small fabric balloon and can provide up to 79 N blocking force. With a rotatory sensor, it can also monitor the actual length of the cable. The soft pneumatic actuator can achieve omnidirectional bending and extension by regulating the state of the 4 cable locking systems. By experiments, we verify the work principle of cable locking system. The actuator here can also vary its stiffness from 6 N/m to 97 N/m by antagonism.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design, Biomimetics
Abstract: Layer jamming and positive pressure jamming demonstrated great potential in soft robotic applications. The combination of these technologies can increase the performance of variable stiffness-oriented designs. Inspired by the shape of sea shell radial ribs, we introduce a planar lightweight device that can be easily adapted to different application scenarios, providing both significant stiffness variation and high loadbearing capabilities. Exploiting the ease of the system in terms of design and manufacturing, we tested the device with a different number of layers. It shows higher performances than standard layer jamming systems: in particular, the 1 layer per side version (7.5g) shows a variable stiffness ratio of 64:1 and a force required to reach a 10 mm deflection equal to 19N. The same values for the 5 layers per side version (17.2g) are 42.5:1 and 62N. These values are in line with the most promising innovative approaches reported in the literature on layer jamming. In addition, the presented results allow making a comparison between the introduced device and the biological counterpart in terms of performance, showing the validity of sea shells as a bioinspiration source for variable stiffness systems.

Keywords: Soft Sensors and Actuators, Computational Geometry, Soft Robot Materials and Design
Abstract: Sensorized hydrogels are attracting tremendous interest in the manufacture of flexible strain sensors due to their impressive responses and tunable mechanical properties. However, many require extensive fabrication processes and hazardous raw materials, making their practical application difficult. Here, we demonstrate how the parameters of mesoscale cellular mesh sensors can be varied to control and tune the response characteristics of a biocompatible gelatin-based hydrogel using a straightforward fabrication process and readily available low-cost materials. An analytical model is derived to validate the experimental results, providing a framework for design and optimization of sensor morphologies.

Using this, 40% changes in gauge factor are demonstrated with no change in material properties, indicating that our in-plane cellular structures are a substantial and feasible method to control the sensitivity of flexible and stretchable strain sensors. We use the structures to demonstrate wearable proprioceptive devices, anisotropic bidirectional responses, and localization of a tactile stimulus.

Keywords: Grasping, Grippers and Other End-Effectors, Soft Robot Materials and Design
Abstract: In Japan, there is a growing demand for automated silkworm farming system. In this paper, we propose a soft robotic gripper which can grasp silkworm and perform splitting operation after mating. The gripper consists of two soft fingers driven by the pulling motion of an air cylinder for the silkworm grasping. A soft belt driven by the same cylinder performs the splitting operation by a rotation motion. Samples of male and female silkworms were fabricated using silicone rubber were used in the splitting experiments. Two types of soft belts with flat and pleated geometries were experimental tested and the success rate was found to be higher with the pleated typed belt. Appropriate operation conditions were also found through the splitting experiments using the silkworm samples. Finally, experiments were performed on living silkworms provided by our industrial partner and the split operation was successful.

Keywords: Grippers and Other End-Effectors, Biomimetics, Grasping
Abstract: Suction is a nature-inspired adhesion strategy which has been successfully applied in industry for decades. Their high adhesive force and energy efficiency make suckers light weight and low cost. However, the requirement for compact grippers conflicts with the bulky and heavy vacuum pumps used in existing suckers. This work proposes a novel hydrogel-actuated soft sucker inspired by the octopus sucker to realise compact, compliant and adaptive suction which needs no external vacuum supply. The sucker is actuated through volume change within a double-network, thermo-sensitive hydrogel. When the hydrogel is heated, its molecular structure collapses, generating a suction force and simultaneously secreting water around the sucker rim to strengthen the suction. When the hydrogel is cooled, it reabsorbs water, recovering its initial shape and eliminating the suction force. On a dry on-land surface, the proposed sucker is capable of adhering to rough surfaces by utilizing water secretion, similar to the mucus secretion of octopus suckers. Underwater, the sucker further exhibits reversible attachment and detachment capability. Simulation results and experimental results demonstrate the practicality of this suction strategy. By applying a current of 0.3 A to generate joule heat, pressure differentials of -4.54 kPa and -4.02 kPa with respect to atmospheric pressure can be generated underwater and on land, respectively. We believe this hydrogel-actuated soft sucker is a significant new technology for next-generation safe, compliant and compact robotic suckers.

Keywords: Grippers and Other End-Effectors, Soft Sensors and Actuators, Multifingered Hands
Abstract: Advances in robotics and rapid prototyping have spurred interest in soft grippers across diverse fields ranging from medical devices to warehouse robotics. With this growing interest, it is imperative to create straight-forward soft grippers with embedded sensing that are more accessible to people outside of the soft robotics community. The DragonClaw — a 3D-printable, pneumatically actuated, three-fingered dexterous gripper with embedded magnetic tactile sensing — is intended to bridge this gap. The 2-DOF thumb design allows for a range of precision and power grasps, enabling the DragonClaw to complete a modified Kapandji test for dexterous ability. The operating range of the gripper is characterized through experiments on grip strength and finger blocking force. Further, the integrated magnetic sensor, ReSkin, is successfully demonstrated in a closed-loop control task to respond to external disturbances. Finally, the documentation, bill of materials, and detailed instructions to replicate the DragonClaw are made available on the DragonClaw website, encouraging people with wide ranging expertise to reproduce this work. In summary, the novelty of this work is the integration of soft robotic gripper feedback in a form factor that can easily be reproduced by inexpensive, simplified manufacturing methods.

Keywords: Legged Robots, Compliant Joint/Mechanism, Computational Geometry
Abstract: Bio-inspired soft robotic legs can be designed by utilizing continuous deformation to perform desired functions such as increasing propulsion force. Previous studies of legged robots have improved locomotion performance by simplifying animal legs as a single spring and mimicking the function of its elasticity during locomotion. This study proposes a one-piece 3D-printed leg that can kick the ground backward strongly by increasing the horizontal component of the elastic force (i.e., by designing two-dimensional elasticity). The geometry and stiffness of the leg were optimized via a combination of physical simulation and a genetic algorithm to achieve the function. Experiments using a prototype hexapod robot were conducted to compare a leg designed using the proposed method and two additional deteriorated types of legs by measuring locomotion speed. Angle of attack (angle at which the legs touch the ground) was also changed in this experiment. The experimental results indicate that designing the two-dimensional elasticity of legs can contribute to increasing propulsion force, resulting in higher locomotion speed. This study suggests that soft robotic parts with various functions, such as hands and arms, can be designed using continuous deformation and one-piece 3D-printed parts.

Keywords: Grippers and Other End-Effectors, Additive Manufacturing, Soft Robot Materials and Design
Abstract: Grasping parts of inconsistent shapes, sizes and weights securely requires accurate part models and custom gripper fingers. Compliant grippers are a potential solution; however, each design approach requires the solution of unique problems. In this case, the durability and reliability of half lips (at least 1400 cycles) to perform consistently as springs of a specified stiffness (0.5N/mm) and placement (5mm). Moreover, the challenge of low and small (3mm, 0.01kg bolt or Allen key) objects is addressed through vertical squeeze-in, implemented using an incline, lip and flex limiter as part of a 3D printed TPC spring. The squeeze-in phenomena are verified on large objects through a 30mm, 1.66kg common rail. Experimental results demonstrate the reliability when given a human-specified location for gripping, without the need for jigs or fixtures. Finally, the tested design is assessed for potential fulfillment of 7 of the United Nations sustainable development goals.

Keywords: Simulation and Animation, Soft Robot Materials and Design, Wearable Robots
Abstract: Multi-pouch inflatable holding structure are designed using commercial finite element analysis (FEA) and developed to achieve higher payload using high performance fabric materials. In previous literature, only nylon-based fabric material is used for such structure with limited shape design. Herein we present a multi pouch inflatable holding structure using lightweight and stiffer fabric. From there, the weight of the structure is reduced 40% while the payload is increased 1.5 times. By using FEA simulation, we explored different design variables such as material properties, geometry and air volume control. Stiffness modulation method is also used in current multi-pouch holding structure. By integration of jamming technology, we further doubled the payload of such structure.

Keywords: Additive Manufacturing, Soft Sensors and Actuators, Soft Robot Materials and Design
Abstract: When developing or designing biomimetic robotic fingers with rigid and soft components and integrated sensors, fabrication is often a bottle-neck when assembling and casting processing techniques are used. This study introduces a thermoplastic multi-material fabrication approach that allows the printing of fingers with incorporated sensing elements in a single shot. Thermoplastics and thermoplastic elastomers based materials have been selected to demonstrate the circular fabrication process. To exhibit the potential of the method, a sensorized multi-material finger was fabricated using polypropylene (PP) for the rigid bone, styrene-based tri-block co-polymer (TPS) for the soft skin and resistive composites based on TPS and carbon black (CB) for the sensing. The 3D printer was equipped with combined pellet- and filament-based extruders to enable the combined fabrication processing of the materials without additional assembling. This allowed the exploration of a range of designs with different geometric and infill properties. To demonstrate the circular process, the fabricated fingers were recycled and the mechanical properties did not result in a visible degradation. The described multi-material fabrication of soft robotic components allows time efficiency of the production method and the reusability of the materials, which contribute to establishing a sustainable circular process in the future.

Keywords: Soft Robot Applications, Soft Sensors and Actuators, Soft Robot Materials and Design
Abstract: Special care must be taken when assembling and disassembling complex capital goods since incorrect handling, damage of the goods or delays can represent economic losses. However, challenges related to the automation of the complex handling task and the time of the process led to the research of solutions to increase the speed and decrease its cost. This article introduces the handling process for disassembling turbine blades, its challenges, and precisely a solution based on soft material grippers for adaptive grasping. We present a gripping method to component-friendly hold and handle aircraft engine turbine blades using soft materials. Within this work, we address the design of the soft material gripper, prove its functionality through experiments and assess the behavior of the gripper during the process of the blade's handling and disassembly.

Keywords: Grasping, Grippers and Other End-Effectors, Soft Robot Materials and Design
Abstract: In this paper, the design and demonstration of a shape-forming soft gripper with a donut body is explored. The vacuum-powered donut soft gripper has a 2.50 mm thick silicone membrane and is filled with 7.50 g of polyester fiberfill to allow shape-forming around the target object. Unlike other vacuum-powered soft grippers where the interior materials are mostly hard, our donut soft robot is inspired by a vacuum bedding storage bag, which provides a soft touch to the target object while allowing the gripper to form the required shape around the target object when actuated. Polyester fiberfill contains excelling flexibility and resiliency, it can easily deform based on its surroundings but also return to its original shape quickly when the external force is removed, making it a promising candidate for a shape forming soft gripper. The donut soft gripper’s physical attributes include four indents at the base, with an outer diameter of 84.62 mm, inner diameter of 12.92 mm, and thickness of 40.00 mm. With the donut robot filled with polyester fiberfill, the donut parameters are optimized for bearing weight and has the best shape forming ability. The donut soft robot is capable of securely holding objects of different shapes, including a miniature teapot, a polygon ball, a Lego block, a spice bottle, as well as soft objects like a tomato.

Keywords: Soft Robot Materials and Design, Soft Robot Applications, Soft Sensors and Actuators
Abstract: Soft robotic actuators possess several unique characteristics, such as being generally compliant and lightweight, making them suitable for safe human interaction to be deployed in various industries. However, they are often designed for an intended purpose, making them impractical for a different task. This paper aims to introduce a new way of utilising a new class of soft silicone actuators capable of incorporating them into applications that require both pushing and pulling. The dual multilayer extension actuator (DMEA) is compact and lightweight at 8 g, capable of an extension ratio of 300% and a high pulling force-to-weight ratio of 200 with the assistance of vacuum pressure at 30% extension ratio. The fabrication of the DMEA is described in detail and followed by characterisation tests of the DMEA compared to the FEA model. Finally, we showcase the DMEA pulling a 3D-printed arm as a potential assistive device and demonstrate the DMEA versatility by deploying the DMEA onto common household products like scissors and kitchen tongs.

Keywords: Soft Robot Materials and Design, Human-Centered Robotics, Service Robots
Abstract: Edible robotics is an emerging research field with potential use in environmental, food, and medical scenarios. In this context, the design of edible control circuits could increase the behavioral complexity of edible robots and reduce their dependence on inedible components. Here we describe a method to design and manufacture edible control circuits based on microfluidic logic gates. We focus on the choice of materials and fabrication procedure to produce edible logic gates based on recently available soft microfluidic logic. We validate the proposed design with the production of a functional NOT gate and suggest further research avenues for scaling up the method to more complex circuits.

Keywords: Soft Robot Materials and Design, Biologically-Inspired Robots, Soft Sensors and Actuators
Abstract: Snake robots are characterized by their ability to navigate through small spaces and loose terrain by utilizing efficient cyclic forms of locomotion. Soft snake robots are a subset of these robots which utilize soft, compliant actuators to produce movement. Prior work on soft snake robots has primarily focused on planar gaits, such as undulation. More efficient spatial gaits, such as sidewinding, are unexplored gaits for soft snake robots. We propose a novel means of constructing a soft snake robot capable of sidewinding, and introduce the Helical Inflating Soft Snake Robot (HISSbot). We validate this actuation through the physical HISSbot, and demonstrate its ability to sidewind across various surfaces. Our tests show robustness in locomotion through low-friction and granular media.

Keywords: Grippers and Other End-Effectors, Soft Robot Materials and Design, Underactuated Robots
Abstract: This work describes the development of a hydraulic knuckle designed to modulate joint stiffness in an underactuated, underwater gripper. The knuckles are pressurized with water to control their stiffness. Compression and tension characterization showed that the knuckles can provide up to 34N of resistive force in compression and 47 N of resistive force in tension. Stiffness of the knuckles was found to vary linearly with pressure. A parallel, tendon-driven underactuated gripper was fabricated to explore two relationships: finger configurations vs. knuckle hydraulic pressure and joint stiffness vs. grasp strength. This gripper demonstrated that softer knuckles enable a wrap grasp and stiffer knuckles enable a pinch grasp. Grasp strength testing showed that the planar hand can resist up to 23 N of force at 200 mA motor current, and stiffer grasps can sustain greater pull out forces.

Keywords: Soft Robot Materials and Design, Compliant Joint/Mechanism, Tendon/Wire Mechanism
Abstract: Shape change enables new capabilities for robots. One class of robots capable of dramatic shape change is soft growing "vine" robots. These robots usually feature global actuation methods for bending that limit them to simple, constant-curvature shapes. Achieving more complex "multi-bend" configurations has also been explored but requires choosing the desired configuration ahead of time, exploiting contact with the environment to maintain previous bends, or using pneumatic actuation for shape locking. In this paper, we present a novel design that enables passive, on-demand shape locking. Our design leverages a passive tip mount to apply hook-and-loop fasteners that hold bends without any pneumatic or electrical input. We characterize the robot’s kinematics and ability to hold locked bends. We also experimentally evaluate the effect of hook-and-loop fasteners on beam and joint stiffness. Finally, we demonstrate our proof-of-concept prototype in 2D. Our passive shape locking design is a step towards easily reconfigurable robots that are lightweight, low-cost, and low-power.

Keywords: Soft Robot Materials and Design, Wearable Robots, Soft Robot Applications
Abstract: Textiles have emerged as a potential material class for robots that can be worn as regular garments in various forms and arrangements. Despite tremendous progress, textile-based actuation or energy-storage systems are in need of higher performance, more sustainable, safer, and abundant materials. Carbon is an excellent candidate for flexible electrodes, yet most available electrodes suffer from carbon-to-carbon charge transfer losses. Activated carbon cloth (ACC) is a promising electron-to-ion transducer material that combines high specific surface area and monolithic structure that offers the possibility to transfer electrons within a continuous structure of even a meter scale without carbon-to-carbon contacts. This contrasts with composite electrodes (CEs) that experience repulsion of like charges upon charging, in turn rendering a charged composite electrode less conductive due to an increased distance for electron tunneling. Moreover, as the formation of an electrical double-layer at the electrode surface increases the local charge density, the impedance is expected to decrease. In CEs, this increase is obscured by interparticle contacts, but can be significant in ACCs due to its monolithic structure. The monolithic nature of ACC thus results in unique electrical characteristics: upon injecting more charge to an electroactive laminate with ACC electrodes, the system becomes increasingly conductive. This work investigates the in-situ impedance of an ACC electrode whilst charging intermittently. Favorable impedance behavior makes ACC an attractive electrode material for wearable technologies and medical devices.

Keywords: Soft Robot Materials and Design, Biologically-Inspired Robots, Soft Sensors and Actuators
Abstract: Twisted and coiled polymer (TCP) actuator is a promising novel actuator, exhibiting attractive properties of light weight, low cost, high energy density and simple fabrication process. However, coiled polymer actuators have low non-resonant actuation frequencies because of the time needed for heat dissipation during the relaxation phase. This restricts them to applications where frequencies are less than 0.5 Hz. In this paper, we present a robotic fish driven by a novel TCP–spring antagonistic pair at high frequencies in water. By minimizing the distance between the TCP and the spring, the robot achieved a maximum swimming velocity of 25.7 mm/s (11.5% body length/s) by undulatory flapping of its caudal fin at a frequency of 2 Hz using periodic Joule heating. This demonstrates the highest frequency and swimming speed achieved for a TCP actuator in a practical aquatic application. The design, fabrication and verification of the fish robot, including characterisation of the TCP actuators in air and water, are presented. A study on different fin stiffness is also presented. This paper provides a new route to raising the actuation frequency of TCPs through thermomechanical design and shows the possibility of using TCPs at high frequency in aqueous environments.

Keywords: Soft Robot Applications, Haptics and Haptic Interfaces, Force and Tactile Sensing
Abstract: This paper reports on the use of a soft probe as a haptic exploratory device with Force/Moment (F/M) Readings at its base to determine the position of extremely lightweight and delicate objects. The proposed method uses the mathematical relationships between the deformations of the soft probe and the F/M sensor outputs, to reconstruct the shape of the probe and the position of the touched object. The Cosserat rod theory was utilized in this way under the assumption that only one contact point occurs during the exploration and friction effects are negligible. Soft probes in different sizes were designed and fabricated using a Form3 3D printer and Elastic50A resin, for which the effect of gravity is not negligible. Experimental results verified the performance of the proposed method that achieved a position estimation performance of 5mm, while different external forces (between 0.01N to 1.5N) were applied along the soft probes to resemble the condition of touching lightweight objects. Eventually, the method is used to estimate position of some points in a delicate card house structure.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design, Hydraulic/Pneumatic Actuators
Abstract: Inflatable actuators are regularly used to induce large complex deformations in soft robotic systems. Their actuation speed is typically low, as it takes time for fluids to be pushed through narrow pressure supply tubes. To overcome this limitation, we take inspiration from nature and create actuators that can suddenly release build up elastic energy, by means of breaking a physical bond. Where in nature these ruptures are irreversible, here we use the reversible adhesion of a suction cup to accomplish the same behavior. First, we show that the released elastic energy originates from an adiabatic transition from the constrained to the free inflation curve of the actuator. Next, we numerically analyze this process and give design considerations for maximizing energy release. Lastly, we build a prototype actuator that displays this type of energy release and demonstrate that it can be used for jumping.

Keywords: Soft Robot Materials and Design, Soft Robot Applications, Grippers and Other End-Effectors
Abstract: Performing adaptive grasping tasks with unknown shapes is challenging for robotic grippers. The emergence of soft robotics brings a new perspective to address this challenge, since soft robots have unique merits of lightweight, inherent softness and natural compliance owing to the soft materials and actuation methods. In this paper, inspired by soft mesh structures, we propose a soft robotic gripper based on flexible 3D-printed mesh skeleton. With this new design, the soft gripper can effectively contract and grasp various objects upon vacuum actuation. The 3D-printed stretchable mesh allows the gripper to perfectly match the shapes of target objects in less than 1s. This compliant feature allows the soft gripper to safely handle fragile objects, with the potential to be customized for specific objects and tasks. The developed gripper is expected to be useful for various pick-and-place tasks such as food handling, cosmetic packaging, and fruit picking.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design
Abstract: Pneumatic soft robotic technologies promise to revolutionize automation, medicine, human-computer inter- action, and beyond. Yet without a sufficiently lightweight, compact, power-dense gas compressor, these wearable and mobile pneumatic devices cannot surpass tethered laboratory demonstrations. In this article, we introduce a gas compressor that converts the gas and energy release of sodium azide propellant mixtures into pressure-volume work. By integrating high-energy density solid fuels and compressor components into one piston-cylinder apparatus, we reduce system complexity, size, and weight. Our experiments provide initial thermody- namic propellant characterization and single-stroke compressor demonstrations.

Keywords: Biologically-Inspired Robots, Medical Robots and Systems, Soft Robot Materials and Design
Abstract: In the medical field, it is essential to remove delicate tissues from the body without damaging them or disturbing the surroundings. Current tissue transport mechanisms depend on the tissue composition and shape of the transported tissue, which results in problems such as clogging. This study presents a soft transportation mechanism for tissues inspired by the longitudinal muscles associated with the peristaltic movement of the gastrointestinal tract. The mechanism is designed as a conveying toroid that turns itself inside out in a continuous motion. A fabrication method was developed to manufacture a small-sized silicone toroid, filled with lubricating liquid. Comparable to the peristaltic movement, the silicone toroid adapts its shape to the transported tissue which results in a soft seal around the tissue. The toroid conveys the tissue while locking it at a stationary spot. A prototype was built to evaluate the transport efficiency of the conveying toroid in differently curved pathways. The preliminary experiments showed good transport efficiency, revealing the potential of the proposed soft transport mechanism for medical, and other transport applications.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design
Abstract: As the task-complexities demanded of soft robots continue to increase, so too does the need for soft sensorized skins which can provide complex tactile feedback. Here we consider the detection of asymmetric deformations by designing and validating an easy-to-fabricate hydrogel-silicone composite sensor for deployment in an underactuated soft robotic manipulator. For proprioception and exteroception, this skin can sense asymmetric bifurcations in a stretchable skin without affecting functionality. Our method facilitates the sensor's use in a wide range of soft robotic actuators: we present its ability to respond to repeated, incremental, and oscillating stimuli in the soft manipulator, and demonstrate its ease of integration into a closed-loop control system. We experimentally find the sensors capable of withstanding over 200% strain before the onset of delamination.

Keywords: Grasping, Soft Robot Applications, Biomimetics
Abstract: The suction capabilities of octopuses' arms are an evolutionary marvel in surface adhesion that have long fascinated scientists and engineers in soft robotics. In this study, we report the design and the fabrication of a pad inspired by the suckers of the octopus textit{O. vulgaris}. The pad houses several pores connected to a vacuum system on one end and covered by a soft membrane on the other end. The membrane is used as an interface between the pad and payloads. Vacuum actuation strains the membrane resulting in a secondary passive vacuum space between the pad and a payload. Material composition and geometric parameters of the pad were first optimized using finite element analysis to maximize both conformability to rough surfaces and adhesion force. The optimized pad exhibited a~73% enhancement in adhesion force compared to a traditional pad, with the ability to adhere strongly to objects with smooth, rough, or wet surfaces, even with a small initial contact area. Finally, the pad was tested in a single joint soft finger mounted on a small gripper to showcase basic gripping capabilities on a wide range of objects.

Keywords: Modeling, Control, and Learning for Soft Robots, Simulation and Animation, Soft Robot Materials and Design
Abstract: Controller design for continuum robots maintains to be a difficult task. Testing controllers requires dedicated work in manufacturing and investment into hardware as well as software, to acquire a test bench capable of performing dynamic control tasks. Typically, proprietary software for practical controller design such as Matlab/Simulink is used but lacks specific implementations of soft material robots. This intermediate work presents the results of a toolchain to derive well-identified rod simulations. State-of-the-art methods to simulate the dynamics of continuum robots are integrated into an object-oriented implementation and wrapped into the Simulink framework. The generated S-function is capable of handling arbitrary, user-defined input such as pressure actuation or external tip forces as demonstrated in numerical examples. With application to a soft pneumatic actuator, stiffness parameters of a nonlinear hyperelastic material law are identified via finite element simulation and paired with heuristically identified damping parameters to perform dynamic simulation. To prove the general functionality of the simulation, a numerical example as well as a benchmark from literature is implemented and shown. A soft pneumatic actuator is used to generate validation data, which is in good accordance with the respective simulation output. The tool is provided as an open-source project.

Keywords: Soft Robot Applications, Soft Robot Materials and Design, Physical Human-Robot Interaction
Abstract: Robots that share activity spaces or physically interact with humans typically benefit from appropriate payload capacity, extensible workspace, low weight, safety, and space efficiency. The soft origami design and mechanism can meet many of these beneficial factors; however, achieving a high payload capacity remains challenging. Moreover, with the conventional origami design technique, it is difficult to achieve a high degree of design freedom for the entire system. In this study, we developed a soft origami arm module with high variable stiffness (x300) and spatial efficiency (compressed x3.1). The

buckling of facets into a cylindrical tube followed by its pressurization enables the arm to be highly stiffened. High-pressure capacity was obtained via the sewing-heat press fabrication process. The tendon-pneumatic antagonistic actuation was utilized to prevent unintentional gravity-induced deformation. An analytical model was developed and compared to the experimental results. Two robotic demonstrations were performed to examine the expandability of the modules. A variable-length robotic arm that mimics a human arm was built to manipulate typical objects. Additionally, a soft rover, which could carry 14 kg of weight and change its volume 29 times for improved

spatial efficiency, was developed. This research suggests a new design methodology for practical soft robotic systems.

Keywords: Soft Robot Materials and Design, Modeling, Control, and Learning for Soft Robots, Soft Robot Applications
Abstract: Driven by performance criteria and requirements from specific applications in healthcare for instance, the soft robotics community has created a huge amount of different designs for pneumatically actuated soft robots. The assessment with regard to these criteria usually involves a full characterisation of the soft robotic system. In order to support these efforts during the prototyping phase and standardise assessment procedures, a physical platform is described in this paper that allows to gain essential insights into the characterisation and validation of control algorithms for pneumatically driven soft robots. The platform can be connected to a MATLAB Graphical User Interface allowing to send pressure values as well as record and plot data, and, hence, it is able to actuate and characterise main features of soft robots, such as the kinematics/dynamics, stiffness and force capability. The user can choose between two control units including the NI USB-6341 and Arduino Due. These components facilitate implementing and validating control algorithms using different tools, e.g., MATLAB/Simulink. To demonstrate the feasibility and functionalities of our platform, three soft robotic systems have been analysed. We present characterisation results for a variable stiffness joint, the kinematics results during the inflation of an elastic membrane and the validation of an open-loop control strategy for a soft continuum robot.

Keywords: Soft Robot Materials and Design, Soft Robot Applications, Modeling, Control, and Learning for Soft Robots
Abstract: Soft-bodied crawling animals (like caterpillars and inchworms) exploit their active soft bodies with passive adaptability to achieve efficient locomotion and move on multiple terrains. While several research studies have used this principle for robot development, most existing caterpillar/inchworm-inspired soft robots can still crawl on specific terrain (flat, inner, or outer pipes). To advance state-of-the-art soft robotic technology, we propose here a small soft-bodied crawling robot with electromagnetic legs and passive body adaptation. The robot is driven by neural central pattern generator (CPG)-based control. Due to the combination of its actively contractable/extendable body, passively adaptable interconnected body joints, and electromagnetic legs, the robot can successfully crawl on a variety of metal terrains, including a flat surface, step, slope, confined space, and an inner (concave surface) and outer (convex surface) pipe in both horizontal and vertical directions. Additionally, it can be steered to navigate through a cluttered environment with obstacles. Using the CPG-based control method, the robot’s locomotion speed can be simply regulated by changing a single CPG-frequency control parameter. This small soft robot has the potential to be employed as a robotic system for inner and outer pipe inspection and confined space exploration in the oil and gas industry.

Keywords: Modeling, Control, and Learning for Soft Robots, Sensor-based Control, Soft Robot Applications
Abstract: Enabling reaching capabilities in highly redundant continuum robot arms is an active area of research. Existing solutions comprise of task-space controllers, whose proper functioning is still limited to laboratory environments. In contrast, this work proposes a novel plant-inspired behaviour-based controller that exploits information obtained from proximity sensing embedded near the end-effector to move towards a desired spatial target. The controller is tested on a 9-DoF modular cable-driven continuum arm for reaching multiple set-points in space. The results are promising for the deployability of these systems into unstructured environments.

Keywords: Modeling, Control, and Learning for Soft Robots, Underactuated Robots, Grasping
Abstract: Soft robotics is a branch of robotics that aims to emulate nature by exploring so-called soft materials. Using the embedded softness, various degrees of dexterous grasping can be achieved without the need for advanced controllers. However, when compared to nature (and modern rigid robots) akin levels of dexterity and object manipulation are still missing. When considering the elephant's trunk, for example, whole-body manipulation and sensory feedback are explored for simultaneous robust and adaptive grasping. In this work, we incorporate closed-loop control into soft robotic grasping. Using passivity-based control, whole-body grasping is achieved for planar slender soft manipulators with torque actuation. Our approach also accounts for the underactuation present in these systems and adapts its grasping strategy accordingly. Furthermore, damping injection without velocity measurements is explored to enhance the attenuation of undesired oscillatory motion. The performance of the closed-loop system is evaluated in both simulation and experiments.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design, Sensor-based Control
Abstract: The success of soft robots in displaying emergent behaviors is tightly linked to the compliant interaction with the environment. However, to exploit such phenomena, proprioceptive sensing methods which do not hinder their softness are needed. In this work we propose a new sensing approach for soft underwater slender structures based on embedded pressure sensors and use a learning-based pipeline to link the sensor readings to the shape of the soft structure. Using two different modeling techniques, we compare the pose reconstruction accuracy and identify the optimal approach. Using the proprioceptive sensing capabilities we show how this information can be used to assess the swimming performance over a number of metrics, namely swimming thrust, tip deflection, and the traveling wave index. We conclude by demonstrating the robustness of the embedded sensor on a free swimming soft robotic squid swimming at a maximum velocity of 9.5 cm/s, with the absolute tip deflection being predicted within an error less than 9% without the aid of external sensors.

Keywords: Grasping, Sensor-based Control, Prosthetics and Exoskeletons
Abstract: This paper presents a fully integrated soft-hand exoskeleton enabling automated grasping and releasing functions thanks to the multi-sensory fusion. We use enfolded soft textile actuators to assist the hand, IMU sensors for the arm and hand orientations, and customized soft sensors for tactile feedback from the fingers. We propose a state machine controller that uses the information from tactile sensors and the IMUs to switch between different states to trigger grasping and releasing. The control strategy requires no additional user input; it is designed for meal-eating scenarios. Ten healthy participants instructed not to move their hands tested the system performing 190 trials on five tasks: pouring, drinking, eating a fruit, using a fork, and using a spoon. Objects are randomly placed in four different locations in front of the participant. 97.4% of the trials were successfully accomplished. Furthermore, 78.1% grasps and 83.8% releases are triggered by the first attempt. Compared with no assistant condition of a healthy hand, the system reduced 32.2% of muscle activities and required 2.57 more times to finish the task.

Keywords: Software, Middleware and Programming Environments, Modeling, Control, and Learning for Soft Robots, Soft Robot Materials and Design
Abstract: Soft robots designed within a conventional robotic framework typically consist of individually addressable compliant actuators that are merged together into a deformable body. For inflatable soft robots, this comes at a high cost of tethering which drastically limits their autonomy and versatility. This cost can be decreased by connecting multiple actuators in a fluidic network and partially offloading control to the passive interactions within the network. This type of morphological control necessitates some of the elements in the network to have nonlinear characteristics. However a standardized simulation framework for such networks is lacking. Here, we introduce the open-source python library FONS (Fluidic object-oriented network simulator), a tool for simulating fluidic interactions in lumped fluidic networks of arbitrary size. It is compatible with both gaseous and liquid fluids and supports analytical, simulated and measured characteristics for all components. These components can be defined using a library of standard components or can be implemented as custom objects following a modular object-oriented framework. We show that FONS is capable of simulating a multitude of systems with highly nonlinear components exhibiting morphological control.

Keywords: Soft Sensors and Actuators, Soft Robot Materials and Design, Modeling, Control, and Learning for Soft Robots
Abstract: We propose a novel mechanism that propagates vibration through soft twisted beams, taking advantage of dynamically-coupled anisotropic stiffness to simplify the actuation of walking robots. Using dynamic simulation and experimental approaches, we show that the coupled stiffness of twisted beams with terrain contact can be controlled to generate a variety of complex trajectories by changing the frequency of the input signal. This work reveals how ground contact influences the system’s dynamic behavior, supporting the design of walking robots inspired by this phenomenon. We also show that the proposed twisted beam produces a tunable walking gait from a single vibrational input.

Keywords: Medical Robots and Systems, Sensor Fusion, Computer Vision for Medical Robotics
Abstract: Image-guided biopsy is the most common technique for breast cancer diagnosis. Although magnetic resonance imaging (MRI) has the highest sensitivity for breast lesion detection, ultrasound (US) biopsy guidance is generally preferred due to its non-invasiveness and real-time image feedback during the insertion. In this work, we propose an autonomous robotic system for US-guided biopsy of breast lesions identified on a high resolution pre-operative MRI. After initial registration, the US probe attached to the robotic manipulator compresses the breast tissues until a pre-determined force level is reached. This technique, known as preloading, allows to minimize lesion displacement during the needle insertion. Our workflow integrates a deformation compensation strategy based on patient-specific biomechanical model to update the US probe orientation keeping the target lesion on the US image plane during compression. By relying on a deformation model, the proposed system does not require lesion visibility on US. Experimental evaluation is performed to assess the performance of the system on a realistic breast phantom with 15 internal lesions, considering different preloading forces. The deformation compensation strategy allows to improve localization accuracy, and as a consequence final probe positioning, for all considered lesions. Median lesion localization error is 3.3mm, which is lower than the median lesion radius, when applying a preloading of 2N, which guarantees both minimal needle insertion error and tissue stress.

Keywords: Biologically-Inspired Robots, Modeling, Control, and Learning for Soft Robots, Search and Rescue Robots
Abstract: Soft robotic snakes (SRSs) have a unique combination of continuous and compliant properties that allow them to imitate the complex movements of biological snakes. Despite the previous attempts to develop SRSs, many have been limited to planar movements or use wheels to achieve locomotion, which restricts their ability to imitate the full range of biological snake movements. We propose a new design for the SRSs that is wheelless and powered by pneumatics, relying solely on spatial bending to achieve its movements. We derive a kinematic model of the proposed SRS and utilize it to achieve two snake locomotion trajectories, namely sidewinding and helical rolling. These movements are experimentally evaluated under different gait parameters on our SRS prototype. The results demonstrate that the SRS can successfully mimic the proposed spatial locomotion trajectories. This is a significant improvement over the previous designs, which were either limited to planar movements or relied on wheels for locomotion. The ability of the SRS to effectively mimic the complex movements of biological snakes opens up new possibilities for its use in various applications.

Keywords: Soft Sensors and Actuators, Hydraulic/Pneumatic Actuators, Biologically-Inspired Robots
Abstract: The McKibben pneumatic artificial muscle is a commonly studied soft robotic actuator, and its quasistatic force-length properties have been well characterized and modeled. However, its damping and force-velocity properties are less well studied. Understanding these properties will allow for more robust dynamic modeling of soft robotic systems. The force-velocity response of these actuators is of particular interest because these actuators are often used as hardware models of skeletal muscles for bioinspired robots, and this force-velocity relationship is fundamental to muscle physiology. In this work, we investigated the force-velocity response of McKibben actuators and the ability to tune this response through the use of viscoelastic polymer sheaths. These viscoelastic McKibben actuators (VMAs) were characterized using iso-velocity experiments inspired by skeletal muscle physiology tests. A simplified 1D model of the actuators was developed to connect the shape of the force-velocity curve to the material parameters of the actuator and sheaths. Using these viscoelastic materials, we were able to modulate the shape and magnitude of the actuators’ force-velocity curves, and using the developed model, these changes were connected back to the material properties of the sheaths.

Keywords: Modeling, Control, and Learning for Soft Robots, Simulation and Animation, Soft Robot Materials and Design
Abstract: We present a novel general model that unifies the kinematics of constant curvature and constant twist continuum manipulators. Combining this kinematics with energy-based physics, we derive a linear mapping from actuator configuration to manipulator deformation that is analogous to traditional robot forward kinematics. Our model generalizes across manipulators with different sizes, types of bending, and types of actuators, without the need for parameter re-fitting. The combination of generality and linearity makes the model useful for control and planning algorithms. Finally, our model is shown to be accurate through experimental validation on manipulators with pneumatic artificial muscles.

Keywords: Modeling, Control, and Learning for Soft Robots, Soft Sensors and Actuators, Soft Robot Materials and Design
Abstract: One way to achieve large deformations and elon- gation in soft material robots involves the creation of structures made of a number of inflatable elastic membranes. Physical interactions between the inflated membranes or with their environment can lead to shape changes resulting in forces being exerted to the environment. In this paper, we present an analytical model to describe the inflation of a circular elastic membrane, which is constrained by a load, based on finite deformation theory. Our model will allow to understand the deformation, volume change and the height of the mem- brane. Our model can predict the height-pressure trend of the deformed membrane shape. Experimental validation includes the investigation of the membrane inflation under load, open- loop force control involving an inflated membrane, and the inflation of a stack of three actuators. The height-pressure model results lay within the experimental data and predicted the non-linear trend well. The model can be used for open-loop force control within a ±15% error. Also, we present the results for a manipulator made of a series of inflated membranes under load conditions.

Keywords: Modeling, Control, and Learning for Soft Robots, Sensor Fusion, Deep Learning in Robotics and Automation
Abstract: Soft robots are typically approximated as low-dimensional systems, especially when learning-based methods are used. This leads to models that are limited in their capability to predict the large number of deformation modes and interactions that a soft robot can have. In this work, we present a deep-learning methodology to learn high-dimensional visual models of a soft robot combining multimodal sensorimotor information. The models are learned in an end-to-end fashion, thereby requiring no intermediate sensor processing or grounding of data. The capabilities and advantages of such a modelling approach are shown on a soft anthropomorphic finger with embedded soft sensors. We also show that how such an approach can be extended to develop higher level cognitive functions like identification of the self and the external environment and acquiring object manipulation skills. This work is a step towards the integration of soft robotics and developmental robotics architectures to create the next generation of intelligent soft robots.

Keywords: Biologically-Inspired Robots, Simulation and Animation, Soft Robot Materials and Design
Abstract: Robot adaptation is typically limited to adaptive control policies or actuated morphology changes (such as shape change). When part of a robot body is removed it is typically viewed as an injury that must be adapted to; the potential for adaptation through subtraction by removal of body components has not yet been considered. Biological systems, on the other hand, provide many examples of subtractive adaptation, including gene or nucleotide deletion at the evolutionary scale, apoptosis at the cellular scale, and autotomy (the deliberate loss of an appendage) at the organismal scale. In this work, we consider the adaptive potential of evolved autotomy in simulated soft robots. To do so we jointly evolved the body plans, control policies, and/or which body parts to remove for soft robots. Our results show that autotomy, rather than policy adaptation, sometimes evolved to change the robot's heading when commanded. In most trials, policy adaptation was favored by the evolutionary algorithm over autotomy for changing heading. But the fact that autotomy appeared as a viable solution in some evolving populations, both when starting body plans were evolved or set manually, suggests that this form of morphological adaptation may be useful for future soft robots.

Keywords: Modeling, Control, and Learning for Soft Robots, Wearable Robots, Soft Robot Applications
Abstract: Just like in humans vision plays a fundamental role in guiding adaptive locomotion, when designing the control strategy for a walking assistive technology, the use of Computer Vision may substantially improve modulation of the assistance based on the external environment. In this work, we developed a hip exosuit controller able to distinguish among three different walking terrains through the use of an RGB camera and to adapt the assistance accordingly. The system was tested with seven healthy participants walking throughout an overground path comprising of staircases and level ground. Subjects performed the task with the exosuit disabled (Exo Off ), constant assistance profile (Vision Off ), and with assistance modulation (Vision On). Our results showed that the controller was able to classify in real-time the path in front of the user with an overall accuracy per class above the 85%, and to perform assistance modulation accordingly. Evaluation related to the effects on the user showed that Vision On was able to outperform the other two conditions: we obtained significantly higher metabolic savings than Exo Off, with a peak of ≈ −20% when climbing up the staircase and ≈ −16% in the overall path, and than Vision Off when ascending or descending stairs. Such advancements in the field may yield to a step forward for the exploitation of lightweight walking assistive technologies in real-life scenarios.