Stiffness variation and real-time position feedback are critical for any robotic system but most importantly for active and wearable devices to interact with the user and environment. Currently, for compact sizes, there is a lack of solutions bringing high-fidelity feedback and maintaining design and functional integrity. In this work, we propose a novel minimal clutch with integrated stiffness variation and real-time position feedback whose performance surpasses conventional jamming solutions. We introduce integrated design, modeling, and verification of the clutch in detail. Preliminary experimental results show the change in impedance force of the clutch is close to 24-fold at the maximum force density of 15.64 N/cm2. We validated the clutch experimentally in (1) enhancing the bending stiffness of a soft actuator to increase a soft manipulator's gripping force by 73%; (2) enabling a soft cylindrical actuator to execute omnidirectional movement; (3) providing real-time position feedback for hand posture detection and impedance force for kinesthetic haptic feedback. This manuscript presents the functional components with a focus on the integrated design methodology, which will have an impact on the development of soft robots and wearable devices.
University of Pennsylvania（宾夕法尼亚大学）；Toyota Research Institute North America（丰田北美研究院）
Soft robotic actuators are safe and adaptable devices with inherent compliance, which makes them attractive for manipulating delicate and complex objects. Researchers have integrated stiff materials into soft actuators to increase their force capacity and direct their deformation. However, these embedded materials have largely been pre-prescribed and static, which constrains the actuators to a predetermined range of motion. In this work, electroadhesive (EA) clutches integrated on a single-chamber soft pneumatic actuator (SPA) provide local programmable stiffness modulation to control the actu…
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…
Oxford Robotics Institute, University of Oxford（牛津大学牛津机器人研究所）
Although research studies in pneumatic soft robots develop rapidly, most pneumatic actuators are still controlled by rigid valves and conventional electronics. The existence of these rigid, electronic components sacrifices the compliance and adaptability of soft robots.} Current electronics-free valve designs based on soft materials are facing challenges in behaviour consistency, design flexibility, and fabrication complexity. Taking advantages of soft material 3D printing, this paper presents a new design of a bi-stable pneumatic valve, which utilises two soft, pneumatically-driven, and symme…
DePaul University（德保罗大学）；University of Arkansas（阿肯色大学）；Clemson University（克莱姆森大学）
We propose a novel tri-fingered soft robotic gripper with decoupled stiffness and shape control capability for performing adaptive grasping with minimum system complexity. The proposed soft fingers adaptively conform to object shapes facilitating the handling of objects of different types, shapes, and sizes. Each soft gripper finger has an inextensible articulable backbone and is actuated by pneumatic muscles. We derive a kinematic model of the gripper and use an empirical approach to map input pressures to stiffness and bending deformation of fingers. We use these mappings to achieve decouple…
Soft robotic systems offer benefits over traditional rigid systems through reduced contact trauma with soft tissues and by enabling access through tortuous paths in minimally invasive surgery. However, the inherent deformability of soft robots places both a greater onus on accurate modelling of their shape, and greater challenges in realising intraoperative shape sensing. Herein we present a proprioceptive (self-sensing) soft actuator, with an electrically conductive working fluid. Electrical impedance measurements from up to six electrodes enabled tomographic reconstructions using Electrical …
Soft Robotic Exogloves for Dexterous Mobility -- Towards Personalized Rehabilitation
Department of Mechanical Engineering, Stevens Institute of Technology（机械工程系，史蒂文斯理工学院）；Faculty of Mechanical Engineering, Stevens Institute of Technology（机械工程学院，史蒂文斯理工学院）
This paper evaluates the capabilities of a soft robotic pneumatic actuator derived from the terrain display haptic device, "The Smart Shoe." The bladder design of the Smart Shoe is upgraded to include a pressure supply and greater output flow capabilities. A bench top setup is created to rigorously test this new type of actuator. The bandwidth and stiffness capability of this new actuator are evaluated relative to forces and displacements encountered during human gait. Four force vs. displacement profiles relevant to haptic terrain display are proposed and tested using sliding-mode tracking co…
Literary Emotions in Motion: A Soft Robotics Installation for Tactile Storytelling
Department of Mechanical Engineering, University of Chile（智利大学机械工程系）；Independent Researcher（独立研究员）；Bolivian Catholic University（玻利维亚天主大学）；Institute of Engineering Sciences, University of O’Higgins（奥希金斯大学工程科学研究所）
Compared to traditional rigid robotics, soft robotics has attracted increasing attention due to its advantages as compliance, safety, and low cost. As an essential part of soft robotics, the soft robotic gripper also shows its superior while grasping the objects with irregular shapes. Recent research has been conducted to improve its grasping performance by adjusting the variable effective length (VEL). However, the VEL achieved by multi-chamber design or tunable stiffness shape memory material requires complex pneumatic circuit design or a time-consuming phase-changing process. This work prop…
A Reconfigurable Pneumatic Joint Enabling Localized Selective Stiffening and Shape Locking in Vine-Inspired Robots
Department of Electrical and Electronics Engineering, Kadir Has University（电子与电子工程系，卡迪尔·哈斯大学）；Department of Computer Engineering, Kadir Has University（计算机工程系，卡迪尔·哈斯大学）；Department of Mechatronics Engineering, Istanbul Bilgi University（机械电子工程系，伊斯坦布尔比尔吉大学）
Temperature Driven Multi-modal/Single-actuated Soft Finger
Graduate School of Engineering Science, Osaka University（大阪大学工程科学研究生院）；National Institute of Advanced Industrial Science and Technology (AIST)（日本国立先进工业科学技术研究院（AIST））
Research on the co-optimization of soft robotic design and control requires rapid means for real-world validation. Existing creation pipelines do not allow for the swift prototyping of soft robots to quickly test various design configurations and control policies. This work proposes a pipeline for rapid iterative design and fabrication of a miniaturized modular silicone-elastomer-based robotic fish. The modular design allows simple and rapid iterations of robotic fishes with varying configurations to assist current research efforts on the development of design optimization methods. The propose…
In this paper, we presented a data-driven framework to optimize the out-of-plane stiffness for soft grippers to achieve mechanical properties as hard-to-twist and easy-to-bend. The effectiveness of this method is demonstrated in the design of a soft pneumatic bending actuator (SPBA). First, a new objective function is defined to quantitatively evaluate the out-of-plane stiffness as well as the bending performance. Then, sensitivity analysis is conducted on the parametric model of an SPBA design to determine the optimized design parameters with the help of Finite Element Analysis (FEA). To enab…
Soft Pneumatic Grippers: Topology optimization, 3D-printing and Experimental validation
Department Mechanical and Aerospace Engineering. India Institute of Technology Hyderbad, Telangana 502285, India（机械与航空航天工程系。印度理工学院海得拉巴分校，特伦敦502285，印度）；CSIRO Robotics, Pullenvale, QLD 4069, Australia（澳大利亚CSIRO机器人部，Pullenvale，QLD 4069，澳大利亚）；Faculty of Mechanical Engineering, Delft University of Technology, Mekelweg 2, Delft, 2628CD, Zuid-Holland, The Netherlands（代尔夫特理工大学机械工程学院，Mekelweg 2号，代尔夫特，2628CD，荷兰泽兰荷兰）
INSA de Toulouse（图卢兹国立应用科学学院）；LAAS/CNRS（法国国家科学研究中心图卢兹实验室）
The Festo air muscle is today one of the most known commercial version of the so-called McKibben pneumatic artificial muscle. A major advantage of handmade McKibben muscles, as well as its commercial versions, lies in the possibility it offers of realizing antagonist muscle actuator on the model of the biceps-triceps system. If pressures are independently controlled in each artificial muscle, it is then possible to define a position-stiffness control of the antagonist actuator by analogy with natural neural control of antagonist skeletal muscles. Such a control however requires a knowledge mod…
A Hybrid Soft Haptic Display for Rendering Lump Stiffness in Remote Palpation
Department of Mechanical Engineering Texas A\&M University College Station, USA；Industrial \& Systems Engineering Texas A\&M University College Station, USA
Robotic Fruits with Tunable Stiffness and Sensing: Towards a Methodology for Developing Realistic Physical Twins of Fruits
School of Engineering and Materials Science, Queen Mary University of London（伦敦女王学院工程与材料科学学院）；Department of Robotics, Ritsumeikan University（立命馆大学机器人学系）
