This paper presents the design and dynamic modelling of a soft pneumatic actuator that can be used to mimic snake or worm-like locomotion. The bond graph technique is used to derive the dynamics of the actuator. To validate the accuracy of the derived dynamic model, we conduct numerical simulations using 20-sim software. Experimental results demonstrate that the soft actuator achieves bi-directional bending and linear displacement, which is essential for mimicking snake or worm-like locomotion
École Polytechnique Fédérale de Lausanne（洛桑联邦理工学院）
We present a fully edible pneumatic actuator based on gelatin-glycerol composite. The actuator is monolithic, fabricated via a molding process, and measures 90 mm in length, 20 mm in width, and 17 mm in thickness. Thanks to the composite mechanical characteristics similar to those of silicone elastomers, the actuator exhibits a bending angle of 170.3 ° and a blocked force of 0.34 N at the applied pressure of 25 kPa. These values are comparable to elastomer based pneumatic actuators. As a validation example, two actuators are integrated to form a gripper capable of handling various objects, hig…
This paper discusses and contests the claims of ``Soft Pneumatic Actuator Fascicles for High Force and Reliability'' a research article which was originally published in the March 2017 issue of the Journal Soft Robotics. The original paper claims that the summed forces of multiple thin-walled extending McKibben muscles are greater than a volumetrically equivalent actuator of the same length at the same pressure. The original paper also claims that the purported benefit becomes more pronounced as the number of smaller actuators is increased. Using reasonable assumptions, the analysis of this pa…
Biology Laboratory, Technische Universit \"a t Berlin, Germany 2 Science of Intelligence, Research Cluster of Excellence, Berlin, Germany
We propose a sensorization method for soft pneumatic actuators that uses an embedded microphone and speaker to measure different actuator properties. The physical state of the actuator determines the specific modulation of sound as it travels through the structure. Using simple machine learning, we create a computational sensor that infers the corresponding state from sound recordings. We demonstrate the acoustic sensor on a soft pneumatic continuum actuator and use it to measure contact locations, contact forces, object materials, actuator inflation, and actuator temperature. We show that the…
This paper presents the design and assessment of a fabric-based soft pneumatic actuator with low pressurization requirements for actuation making it suitable for upper extremity assistive devices for infants. The goal is to support shoulder abduction and adduction without prohibiting motion in other planes or obstructing elbow joint motion. First, the performance of a family of actuator designs with internal air cells is explored via simulation. The actuators are parameterized by the number of cells and their width. Physically viable actuator variants identified through the simulation are furt…
École polytechnique fédérale de Lausanne (EPFL)（洛桑联邦理工学院）
This paper presents the simple synergistic combination of a novel contracting soft pneumatic actuator with a soft clutch (linear brake). The device is designated the Inverting-tube Vacuum ACtuator with Clutch (InVACC). The actuator alone (no clutch) is designated "InVAC" and uses vacuum pressure to invert a thin tube into a shorter section of reinforced flexible tubing. The inverting tube acts as rolling diaphragm and a flexible tendon. This allows the actuator to contract to one third of its extended length. The contractile-force-per-unit-pressure is approximately constant over the stroke. Th…
Soft pneumatic actuators have seen applications in many soft robotic systems, and their pressure-driven nature presents unique challenges and opportunities for controlling their motion. In this work, we present a new concept: designing and controlling pneumatic actuators via end geometry. We demonstrate a novel actuator class, named the folded Pneumatic Artificial Muscle (foldPAM), which features a thin-filmed air pouch that is symmetrically folded on each side. Varying the folded portion of the actuator changes the end constraints and, hence, the force-strain relationships. We investigated th…
Soft robotics technologies have gained growing interest in recent years, which allows various applications from manufacturing to human-robot interaction. Pneumatic artificial muscle (PAM), a typical soft actuator, has been widely applied to soft robots. The compliance and resilience of soft actuators allow soft robots to behave compliant when interacting with unstructured environments, while the utilization of soft actuators also introduces nonlinearity and uncertainty. Inspired by Cerebellum's vital functions in control of human's physical movement, a neural network model of Cerebellum based …
National University of Singapore (NUS)（新加坡国立大学）；Advanced Robotics Center (ARC) at NUS（新加坡国立大学先进机器人中心）
The shoulder is responsible for the movement of the entire upper limb. It is capable of articulating in three degrees-of-freedom (DOF), enabling the arm to perform manipulation actions with incomparable dexterity. Exoskeletons targeting the shoulder must be able to emulate its complex kinematics. While typical architectures have proven to be useful, they employ complex and usually inadequate techniques to match the mobility of the shoulder. A new 2-DOF soft robotic shoulder exoskeleton is presented. Modular soft robotic actuators with separated inflation modules on the exoskeleton are able to …
The vision of creating entirely-soft robots capable of performing complex tasks will be accomplished only when the controllers required for autonomous operation can be fully implemented on soft components. Despite recent advances in compliant fluidic circuitry for mechanical signal processing, the applicability of this technology for soft robot control has been limited by complicated fabrication and tuning processes, and also the need for external signals such as clocks and digital references. We propose a method to develop pneumatic soft robots in which coordinated interactions between multip…
SPADA: A Toolbox of Designing Soft Pneumatic Actuators for Shape Matching based on Surrogate Modeling
Oxford Robotics Institute, University of Oxford（牛津大学牛津机器人研究所）；Institute of Biomedical Engineering, University of Oxford（牛津大学生物医学工程研究所）；University of Genoa（热那亚大学）
Eindhoven University of Technology（埃因霍温理工大学）；University of Twente（特文特大学）
Soft robots are interesting examples of hyper-redundancy in robotics, however, the nonlinear continuous dynamics of these robots and the use of hyper-elastic and visco-elastic materials makes modeling of these robots more complicated. This study presents a geometric Inverse Kinematic (IK) model for trajectory tracking of multi-segment extensible soft robots, where, each segment of the soft actuator is geometrically approximated with multiple rigid links connected with rotary and prismatic joints. Using optimization methods, the desired configuration variables of the soft actuator for the desir…
DePaul University（德保罗大学）；University of Arkansas（阿肯色大学）；Clemson University（克莱姆森大学）
Pneumatic muscle actuators (PMA) are easy-to-fabricate, lightweight, compliant, and have high power-to-weight ratio, thus making them the ideal actuation choice for many soft and continuum robots. But so far, limited work has been carried out in dynamic control of PMAs. One reason is that PMAs are highly hysteretic. Coupled with their high compliance and response lag, PMAs are challenging to control, particularly when subjected to external loads. The hysteresis models proposed to-date rely on many physical and mechanical parameters that are difficult to measure reliably and therefore of limite…
Delft University of Technology（代尔夫特理工大学）；The Chinese University of Hong Kong（香港中文大学）；The University of Manchester（曼彻斯特大学）
Real-time proprioception is a challenging problem for soft robots, which have almost infinite degrees-of-freedom in body deformation. When multiple actuators are used, it becomes more difficult as deformation can also occur on actuators caused by interaction between each other. To tackle this problem, we present a method in this paper to sense and reconstruct 3D deformation on pneumatic soft robots by first integrating multiple low-cost sensors inside the chambers of pneumatic actuators and then using machine learning to convert the captured signals into shape parameters of soft robots. An ext…
Reconfigurable, Transformable Soft Pneumatic Actuator with Tunable 3D Deformations for Dexterous Soft Robotics Applications
Hong Kong University of Science and Technology (HKUST)（香港科技大学）；HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute（香港科技大学深圳-香港协同创新研究院）
Inspired by the dexterous handling ability of an elephant's trunk, we propose a pneumatic actuator that generates diverse bending and extension motions in a flexible arm. The actuator consists of two flexible tubes. Each flexible tube is restrained by a single string with variable length and tilt angle. Even if a single tube can perform only three simple types of motions (bending, extension, and helical), a variety of complex bending patterns can be created by arranging a pair of tubes in parallel and making the restraint variable. This performance takes advantage of the effect of the superpos…
Vision-based FDM Printing for Fabricating Airtight Soft Actuators
Department of Robotics Engineering, Worcester Polytechnic Institute（机器人工程系，沃斯特理工学院）；Department of Computer Science, Worcester Polytechnic Institute（计算机科学系，沃斯特理工学院）；Department of Mechanical and Materials Engineering, Worcester Polytechnic Institute（机械与材料工程系，沃斯特理工学院）；Department of Electrical and Computer Engineering, Worcester Polytechnic Institute（电气与计算机工程系，沃斯特理工学院）
Bilayer bending based soft actuators are widely utilized in soft robotics for locomotion and object gripping. However, studies on soft actuators based on bilayer doming remain largely unexplored despite the often-observed dome-like shapes in undersea animals such as jellyfish and octopus suction cup. Here, based on the simplified model of bending-induced doming of circular bilayer plates with mismatched deformation, we explore the design of soft doming actuator upon pneumatic actuation and its implications in design of multifunctional soft machines. The bilayer actuator is composed of patterne…
Fabric Pneumatic Artificial Muscle-Based Head-Neck Exosuit: Design, Modeling, and Evaluation
Department of Aerospace and Mechanical Engineering, University of Notre Dame（Notre Dame 大学航空航天与机械工程系）；Faculty of Information Technology and Bionics, Pázmány Péter Catholic University（帕兹曼·佩特天主教大学信息科技与生物医学系）；Department of Mechanical Engineering and Robotics Center, University of Utah（犹他大学机械工程系与机器人中心）
