Hydraulically amplified self-healing electrostatic actuators with muscle-like performance

Science ◽  
2018 ◽  
Vol 359 (6371) ◽  
pp. 61-65 ◽  
Author(s):  
E. Acome ◽  
S. K. Mitchell ◽  
T. G. Morrissey ◽  
M. B. Emmett ◽  
C. Benjamin ◽  
...  
Keyword(s):  
High Speed ◽  
Dielectric Breakdown ◽  
Artificial Muscle ◽  
Robotic Arm ◽  
Soft Robotics ◽  
Self Healing ◽  
Electrostatic Actuators ◽  
Robotic Devices ◽  
Soft Actuators ◽  
Wide Potential

Existing soft actuators have persistent challenges that restrain the potential of soft robotics, highlighting a need for soft transducers that are powerful, high-speed, efficient, and robust. We describe a class of soft actuators, termed hydraulically amplified self-healing electrostatic (HASEL) actuators, which harness a mechanism that couples electrostatic and hydraulic forces to achieve a variety of actuation modes. We introduce prototypical designs of HASEL actuators and demonstrate their robust, muscle-like performance as well as their ability to repeatedly self-heal after dielectric breakdown—all using widely available materials and common fabrication techniques. A soft gripper handling delicate objects and a self-sensing artificial muscle powering a robotic arm illustrate the wide potential of HASEL actuators for next-generation soft robotic devices.

Multiple Inputs-Single Accumulated Output Mechanism for Soft Linear Actuators

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyeong Ho Cho ◽  
Ho Moon Kim ◽  
Youngeun Kim ◽  
Sang Yul Yang ◽  
Hyouk Ryeol Choi
Keyword(s):  
Artificial Muscle ◽  
Operating Mode ◽  
Robotic Arm ◽  
Soft Actuator ◽  
Wearable Robots ◽  
Working Principle ◽  
Linear Actuators ◽  
Soft Actuators ◽  
Muscle Actuators ◽  
Further Development

Soft linear actuators (SLAs) such as shape memory alloy (SMA) wires, pneumatic soft actuators, dielectric elastomer actuator, and twisted and coiled soft actuator (TCA) called artificial muscle actuators in general, have many advantages over the conventional actuators. SLAs can realize innovative robotic technologies like soft robots, wearable robots, and bionic arms in the future, but further development is still needed in real applications because most SLAs do not provide large displacement or force as needed. This paper presents a novel mechanism supplementing SLAs by accumulating the displacement of multiple SLAs. It adopts the principle of differential gears in reverse. Since the input units of the mechanism are extensible, more displacement can be accumulated by increasing the number of the input units as many as needed. The mechanism is basically used to accumulate displacements, but can be used to accumulate forces by changing its operating mode. This paper introduces the design and working principle of the mechanism and validates its operation experimentally. In addition, the mechanism is implemented on a robotic arm and its effectiveness is confirmed.

scholarly journals Design of a High-Speed Prosthetic Finger Driven by Peano-HASEL Actuators

2020 ◽  
Vol 7 ◽  
Author(s):  
Zachary Yoder ◽  
Nicholas Kellaris ◽  
Christina Chase-Markopoulou ◽  
Devon Ricken ◽  
Shane K. Mitchell ◽  
...  
Keyword(s):  
High Speed ◽  
Kinematic Model ◽  
Electrical Energy ◽  
Dc Motor ◽  
Self Healing ◽  
Force Output ◽  
Prosthetic Limbs ◽  
Neuromuscular Systems ◽  
Soft Actuators ◽  
Prosthetic Finger

Current designs of powered prosthetic limbs are limited by the nearly exclusive use of DC motor technology. Soft actuators promise new design freedom to create prosthetic limbs which more closely mimic intact neuromuscular systems and improve the capabilities of prosthetic users. This work evaluates the performance of a hydraulically amplified self-healing electrostatic (HASEL) soft actuator for use in a prosthetic hand. We compare a linearly-contracting HASEL actuator, termed a Peano-HASEL, to an existing actuator (DC motor) when driving a prosthetic finger like those utilized in multi-functional prosthetic hands. A kinematic model of the prosthetic finger is developed and validated, and is used to customize a prosthetic finger that is tuned to complement the force-strain characteristics of the Peano-HASEL actuators. An analytical model is used to inform the design of an improved Peano-HASEL actuator with the goal of increasing the fingertip pinch force of the prosthetic finger. When compared to a weight-matched DC motor actuator, the Peano-HASEL and custom finger is 10.6 times faster, has 11.1 times higher bandwidth, and consumes 8.7 times less electrical energy to grasp. It reaches 91% of the maximum range of motion of the original finger. However, the DC motor actuator produces 10 times the fingertip force at a relevant grip position. In this body of work, we present ways to further increase the force output of the Peano-HASEL driven prosthetic finger system, and discuss the significance of the unique properties of Peano-HASELs when applied to the field of upper-limb prosthetic design. This approach toward clinically-relevant actuator performance paired with a substantially different form-factor compared to DC motors presents new opportunities to advance the field of prosthetic limb design.

scholarly journals Dielectric Elastomer Grippers

2021 ◽  
Vol 10 (5) ◽  
pp. 33-36
Author(s):  
Mills Patel ◽  
Rudrax Khamar ◽  
Akshat Shah ◽  
Tej shah ◽  
Bhavik Soneji
Keyword(s):  
Mechanical Properties ◽  
Power Generation ◽  
State Of The Art ◽  
Artificial Muscle ◽  
Dielectric Elastomer ◽  
Soft Robotics ◽  
Artificial Muscles ◽  
Dielectric Elastomer Actuators ◽  
Working Principle ◽  
Soft Actuators

This paper appraisals state-of-the-art dielectric elastomer actuators (DEAs) and their forthcoming standpoints as soft actuators which have freshly been considered as a crucial power generation module for soft robots. DEs behave as yielding capacitors, expanding in area and attenuation in thickness when a voltage is applied. The paper initiates with the explanation of working principle of dielectric elastomer grippers. Here the operation of DEAs include both physics and mechanical properties with its characteristics, we have describe methods for modelling and its introductory application. In inclusion, the artificial muscle based on DEA concept is also formally presented. This paper also elaborates DEAs popular application such as- Soft Robotics, Robotics grippers and artificial muscles.

MXene artificial muscles based on ionically cross-linked Ti3C2Tx electrode for kinetic soft robotics

2019 ◽  
Vol 4 (33) ◽  
pp. eaaw7797 ◽  
Author(s):  
Sima Umrao ◽  
Rassoul Tabassian ◽  
Jaehwan Kim ◽  
Van Hiep Nguyen ◽  
Qitao Zhou ◽  
...  
Keyword(s):  
Structural Reliability ◽  
Artificial Muscle ◽  
Response Speed ◽  
Input Voltage ◽  
Artificial Muscles ◽  
Wearable Electronics ◽  
Bending Strain ◽  
Kinetic Art ◽  
Robotic Devices ◽  
Soft Actuators

Existing ionic artificial muscles still require a technology breakthrough for much faster response speed, higher bending strain, and longer durability. Here, we report an MXene artificial muscle based on ionically cross-linked Ti3C2Tx with poly(3,4 ethylenedioxythiophene)-poly(styrenesulfonate), showing ultrafast rise time of within 1 s in DC responses, extremely large bending strain up to 1.37% in very low input voltage regime (0.1 to 1 V), long-term cyclic stability of 97% up to 18,000 cycles, markedly reduced phase delay, and very broad frequency bandwidth up to 20 Hz with good structural reliability without delamination under continuous electrical stimuli. These artificial muscles were successfully applied to make an origami-inspired narcissus flower robot as a wearable brooch and dancing butterflies and leaves on a tree as a kinetic art piece. These successful demonstrations elucidate the wide potential of MXene-based soft actuators for the next-generation soft robotic devices including wearable electronics and kinetic art pieces.

scholarly journals Dynamics of electrohydraulic soft actuators

2020 ◽  
Vol 117 (28) ◽  
pp. 16207-16213 ◽  
Author(s):  
Philipp Rothemund ◽  
Sophie Kirkman ◽  
Christoph Keplinger
Keyword(s):  
Electric Fields ◽  
High Speed ◽  
Scaling Analysis ◽  
Self Healing ◽  
Electrostatic Actuator ◽  
Fundamental Physics ◽  
Soft Actuators ◽  
External Loads ◽  
Electrohydraulic Actuators ◽  
Inertial Regime

Nature has inspired the design of robots in which soft actuators enable tasks such as handling of fragile objects and adapting to unstructured environments. Those tasks are difficult for traditional robots, which predominantly consist of hard components. Electrohydraulic soft actuators are liquid-filled shells that deform upon the application of electric fields; they excel among soft actuators with muscle-like force outputs and actuation strains, and with actuation frequencies above 100 Hz. However, the fundamental physics that governs the dynamics of electrohydraulic soft actuators is unexplored. Here, we study the dynamics of electrohydraulic soft actuators using the Peano-HASEL (hydraulically amplified self-healing electrostatic) actuator as a model system. Using experiments and a scaling analysis, we discover two dynamic regimes: a regime in which viscous dissipation reduces the actuation speed and a regime governed by inertial effects in which high-speed actuation is possible. For each regime, we derive a timescale that describes the influence of geometry, materials system, and applied external loads on the actuation speed. We also derive a model to study the dynamic behavior of Peano-HASEL actuators in both regimes. Although this analysis focuses on the Peano-HASEL actuator, the presented results may readily be generalized to other electrohydraulic actuators. When designed to operate in the inertial regime, electrohydraulic actuators will enable bio-inspired robots with unprecedented speeds of motion.

scholarly journals Self-contained soft electrofluidic actuators

2021 ◽  
Vol 7 (34) ◽  
pp. eabf8080
Author(s):  
Wei Tang ◽  
Yangqiao Lin ◽  
Chao Zhang ◽  
Yuwen Liang ◽  
Jinrong Wang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
High Performance ◽  
Mechanical Energy ◽  
Artificial Muscle ◽  
Electrical Energy ◽  
Soft Robotics ◽  
Muscle Stretching ◽  
Effective Performance ◽  
Potential Applications ◽  
Soft Actuators

Soft robotics revolutionized human-robot interactions, yet there exist persistent challenges for developing high-performance soft actuators that are powerful, rapid, controllable, safe, and portable. Here, we introduce a class of self-contained soft electrofluidic actuators (SEFAs), which can directly convert electrical energy into the mechanical energy of the actuators through electrically responsive fluids that drive the outside elastomer deformation. The use of special dielectric liquid enhances fluid flow capabilities, improving the actuation performance of the SEFAs. SEFAs are easily manufactured by using widely available materials and common fabrication techniques, and display excellent comprehensive performances in portability, controllability, rapid response, versatility, safety, and actuation. An artificial muscle stretching a joint and a soft bionic ray swimming in a tank demonstrate their effective performance. Hence, SEFAs offer a platform for developing soft actuators with potential applications in wearable assistant devices and soft robots.

Processing of Self‐healing Polymers for Soft Robotics

2021 ◽  
pp. 2104798
Author(s):  
Ellen Roels ◽  
Seppe Terryn ◽  
Fumiya Iida ◽  
Anton W. Bosman ◽  
Sophie Norvez ◽  
...  
Keyword(s):  
Soft Robotics ◽  
Self Healing

scholarly journals Phase-transformation-induced lubrication of earthquake sliding

2017 ◽  
Vol 375 (2103) ◽  
pp. 20160008 ◽  
Author(s):  
Harry W. Green
Keyword(s):  
Phase Transformation ◽  
Dry Friction ◽  
High Speed ◽  
Frictional Resistance ◽  
Low Pressure ◽  
Self Healing ◽  
Strength Recovery ◽  
Endothermic Reactions ◽  
Shear Heating ◽  
Fast Motion

Frictional failure is not possible at depth in Earth, hence earthquakes deeper than 30–50 km cannot initiate by overcoming dry friction. Moreover, the frequency distribution of earthquakes with depth is bimodal, suggesting another change of mechanism at about 350 km. Here I suggest that the change at 30–50 km is from overcoming dry friction to reduction of effective stress by dehydration embrittlement and that the change at 350 km is due to desiccation of slabs and initiation by phase-transformation-induced faulting. High-speed friction experiments at low pressure indicate that exceeding dry friction provokes shear heating that leads to endothermic reactions and pronounced weakening. Higher-pressure studies show nanocrystalline gouge accompanying dehydration and the highest pressure experiments initiate by exothermic polymorphic phase transformation. Here I discuss the characteristic nanostructures of experiments on high-speed friction and high-pressure faulting and show that all simulated earthquake systems yield very weak transformation-induced lubrication, most commonly nanometric gouge or melt. I also show that phase-transformation-induced faulting of olivine to spinel can propagate into material previously transformed to spinel, apparently by triggering melting analogous to high-speed friction studies at low pressure. These experiments taken as a whole suggest that earthquakes at all depths slide at low frictional resistance by a self-healing pulse mechanism with rapid strength recovery. This article is part of the themed issue ‘Faulting, friction and weakening: from slow to fast motion’.

Design and Characterization of Edible Soft Robotic Candy Actuators

MRS Advances ◽  
2018 ◽  
Vol 3 (50) ◽  
pp. 3003-3009 ◽  
Author(s):  
Aditya N. Sardesai ◽  
Xavier M. Segel ◽  
Matthew N. Baumholtz ◽  
Yiheng Chen ◽  
Ruhao Sun ◽  
...  
Keyword(s):  
High School ◽  
The Body ◽  
Soft Robotics ◽  
Compression Tests ◽  
Pneumatic Actuators ◽  
School Division ◽  
Biologically Relevant ◽  
Elementary Aged Children ◽  
Design Competition ◽  
Robotic Devices

ABSTRACTOne of the goals of soft robotics is the ability to interface with the human body. Traditionally, silicone materials have dominated the field of soft robotics. In order to shift to materials that are more compatible with the body, developments will have to be made into biodegradable and biocompatible soft robots. This investigation focused on developing gummy actuators which are biodegradable, edible, and tasty. Creating biodegradable and edible actuators can be both sold as an interactive candy product and also inform the design of implantable soft robotic devices. First, commercially available gelatin-based candies were recast into pneumatic actuators utilizing molds. Edible robotic devices were pneumatically actuated repeatedly (up to n=8 actuations) using a 150 psi power inflator. To improve upon the properties of actuators formed from commercially available candy, a novel gelatin-based formulation, termed the “Fordmula” was also developed and used to create functional actuators. To investigate the mechanics and functionality of the recast gummy material and the Fordmula, compression testing and biodegradation studies were performed. Mechanical compression tests showed that recast gummy materials had similar properties to commercially available candies and at low strain had similar behavior to traditional silicone materials. Degradation studies showed that actuation was possible within 15 minutes in a biologically relevant solution followed by complete dissolution of the actuator afterwards. A taste test with elementary aged children demonstrated the fun, edible, and educational appeal of the candy actuators. Edible actuator development was an entry and winning submission in the High School Division of the Soft Robotics Toolkit Design Competition hosted by Harvard University. Demonstration of edible soft robotic actuators created by middle and high school aged students shows the applicability of the Soft Robotics Toolkit for K12 STEM education.

Vitrimer-based soft actuators with multiple responsiveness and self-healing ability triggered by multiple stimuli

Matter ◽  
2021 ◽  
Author(s):  
Yang Yang ◽  
Huimin Wang ◽  
Shuai Zhang ◽  
Yen Wei ◽  
Xiangming He ◽  
...  
Keyword(s):  
Self Healing ◽  
Soft Actuators
Sign in / Sign up

Export Citation Format

Share Document