scholarly journals Safety-enhanced control strategy of a power soft robot driven by hydraulic artificial muscles

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yunhao Feng ◽  
Tohru Ide ◽  
Hiroyuki Nabae ◽  
Gen Endo ◽  
Ryo Sakurai ◽  
...  
Keyword(s):  
Control Strategy ◽  
Impedance Control ◽  
Artificial Muscle ◽  
Dynamic Compliance ◽  
Artificial Muscles ◽  
Soft Robot ◽  
Compliant Structure ◽  
Safety Features ◽  
Muscle Actuators ◽  
Sudden Load

AbstractPower soft robots—defined as novel robots driven by powerful soft actuators, achieving both powerfulness and softness—are potentially suitable for complex collaborative tasks, and an approach to actuating a power soft robot is the McKibben artificial muscle. This study aims to show the potential of hydraulic artificial muscles to be implemented in a power soft robot with high safety, including higher stability against sudden load separation or impact disturbance, and appropriate dynamic compliance. The stability of a manipulator arm driven by hydraulic muscle actuators is experimentally proven to be higher than that of pneumatic muscle actuators when the stored elastic energy is instantaneously released. Therefore, the hydraulic muscle actuator is a better candidate for actuating a power soft robot. By taking advantage of the incompressible liquid medium and the compliant structure of a hydraulic muscle, a second-order impedance control strategy with a braking method is proposed to improve dynamic compliance without sacrificing the safety features of hydraulic muscles. The results show that the manipulator can be easily shifted by a several-kilogram-level external force and react safely against sudden load change with low angular velocity by the proposed impedance control.

Developing a Novel Robotic Fish With Antagonistic Artificial Muscle Actuators

2017 ◽  
Author(s):  
Sunil Kumar Rajendran ◽  
Feitian Zhang
Keyword(s):  
Heat Dissipation ◽  
Weight Ratio ◽  
Artificial Muscle ◽  
Robotic Fish ◽  
Artificial Muscles ◽  
Underwater Robotics ◽  
Closed Loop System ◽  
Underwater Robots ◽  
Muscle Actuators ◽  
Novel Design

Super-coiled polymer (SCP), one of the newly-developed artificial muscles, has various advantages over traditional artificial muscles in terms of cost, flexibility and power-to-weight ratio. This paper investigates the performance of super-coiled polymer-based actuation in underwater robotics, and presents a novel design of robotic fish using antagonistic SCP actuators. Dynamic model of the robot is derived. An example robotic fish prototype is developed and used in experiments to study SCP actuation for underwater robots. Furthermore, experimental results show that using SCP actuators in robotic fish solves the challenging heat-dissipation problem at ease, thus improving the dynamic response of SCP actuation significantly. A PID controller is designed to regulate the tail flap angle of the designed robotic fish. Simulation results of the closed-loop system are presented to validate the proposed robot design and actuation approach.

Magnetically-doped polydimethylsiloxane for artificial muscle applications

2019 ◽  
Vol 13 (01) ◽  
pp. 1950089
Author(s):  
Erik Ventura ◽  
Cagri Oztan ◽  
Diego Palacios ◽  
Irene Isabel Vargas ◽  
Emrah Celik
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Response ◽  
Load Capacity ◽  
Artificial Muscle ◽  
Artificial Muscles ◽  
Test Results ◽  
Method Of Production ◽  
Muscle Actuators ◽  
Doped Polymer

Artificial muscle actuators demonstrate great potential for improving the quality of life. Recently, polymer muscle actuators have attracted attention due to their inexpensive and highly versatile methods of fabrication along with decent mechanical properties that can mimic those of natural muscles. The aim of this research is to investigate the usability of a magnetite-doped polymer powder, polydimethylsiloxane (PDMS), for artificial muscle actuators through an inexpensive method of production. PDMS samples doped with different levels of magnetite were fabricated using molds that were produced by additive manufacturing. Subsequently, the samples were magnetically and mechanically characterized by investigation of strength, elastic modulus, failure strain and permittivity, which are vital to meet the load capacity. The test results demonstrated that the mechanical and magnetic properties could be tailored as a function of doping level. Matching the mechanical response of these artificial components to those of artificial muscles will reduce the residual stresses, enhance the artificial muscle life and allow wider use of these materials for biomedical applications. This research rendered fabrication of molds possible for various applications where geometric customization of the actuator is required to meet endure severe loads, thanks to the freeform nature of additive manufacturing.

Energetic and Dynamic Effects of Operating Fluid on Fluidic Artificial Muscle Actuators

2013 ◽  
Author(s):  
Michael A. Meller ◽  
Matthew J. Bryant ◽  
Ephrahim Garcia
Keyword(s):  
Artificial Muscle ◽  
Working Fluid ◽  
Artificial Muscles ◽  
Dynamic Tests ◽  
Pneumatic Artificial Muscles ◽  
Vibration Experiment ◽  
Strain Relationship ◽  
Effective Spring Constant ◽  
Muscle Actuators ◽  
Hydraulic Operation

Pneumatic artificial muscles (PAMs) are a relatively common type of lightweight, fluid power actuation. Some disadvantages of PAMs include the compressibility of the working fluid and low damping. These characteristics result in low efficiencies, poor dynamic response, as well as undesired oscillations of the actuators. This paper presents utilizing hydraulic liquid as the working fluid instead of compressed air. Hydraulic operation resulted in almost triple the efficiency of pneumatic operation. The artificial muscles are experimentally characterized both quasi-statically and dynamically. The quasi-static experiments include the tension-strain relationship as a function of pressure, and an actuator net work efficiency analysis. The dynamic tests consist of a free vibration experiment to determine the change in effective spring constant and damping terms. These experiments are conducted for both PAMs and HAMs (hydraulic artificial muscles), and the results are presented herein.

Sliding Mode Impedance Control of a Hydraulic Artificial Muscle

2018 ◽  
Author(s):  
Jonathon E. Slightam ◽  
Mark L. Nagurka ◽  
Eric J. Barth
Keyword(s):  
Sliding Mode ◽  
Impedance Control ◽  
Artificial Muscle ◽  
Lumped Parameter Model ◽  
Superior Performance ◽  
Specific Power ◽  
Artificial Muscles ◽  
Control Approach ◽  
Model Based ◽  
Improved Performance

Hydraulic artificial muscles offer unrivaled specific power and power density and are instrumental to the improved performance and success of soft robotics and lightweight mobile applications. This paper addresses the lack of model-based impedance control approaches for soft actuators such as hydraulic artificial muscles. Impedance control of actuators and robotic systems has been proven to be an effective approach for interacting with physical objects in the presence of uncertainty. A sliding mode impedance control approach based on Filippov’s principle of equivalent dynamics is introduced and applied to a hydraulic artificial muscle. A nonlinear lumped parameter model of the system is presented and a sliding mode impedance controller is derived. Experimental results show superior performance using model-based sliding mode impedance control versus a linear impedance control law in both tracking of position and stiffness when disturbances are introduced.

Dexterous Robot’s Finger Actuated by Pneumatic Artificial Muscle

2011 ◽  
Vol 383-390 ◽  
pp. 920-924 ◽  
Author(s):  
Bing Jing Guo ◽  
Kai Wang
Keyword(s):  
Degrees Of Freedom ◽  
Steel Wire ◽  
Artificial Muscle ◽  
Force Sensor ◽  
Middle Finger ◽  
Artificial Muscles ◽  
Pneumatic Muscle ◽  
Theoretical Support ◽  
Muscle Actuators ◽  
Three Degrees Of Freedom

Through the structural analysis of hand, using mechatronics ideas, robot fingers based on Pneumatic Muscle Actuators (PMA) is designed and manufactured. Referring to the proportion of manual hand, the finger has three degrees of freedom. The far and middle finger joints are coupled of steel wire transmission mechanism, while the middle finger knuckle and the root are driven by a pair of artificial muscles. In order to realize the feedback control of displacement and the tactile force, the finger’s three joints are installed with three R24HS potentiometer and the fingertip is installed with the touch force sensor. The finger design integrates with mechanical structure, sensing, control and driving system. It achieves the integration and modularization in a maximum extent and completes the full theoretical support and experimental verification for the next step integration design of the flexible bionic robot hand.

scholarly journals A Human-Inspired Control Strategy for Improving Seamless Robot-To-Human Handovers

2021 ◽  
Vol 11 (10) ◽  
pp. 4437
Author(s):  
Paramin Neranon ◽  
Tanapong Sutiphotinun
Keyword(s):  
Control System ◽  
Control Strategy ◽  
Impedance Control ◽  
Human Interaction ◽  
Robotic Control ◽  
Natural Manner ◽  
Object Handover ◽  
Overall Performance ◽  
Survey Responses ◽  
Test Outcomes

One of the challenging aspects of robotics research is to successfully establish a human-like behavioural control strategy for human–robot handover, since a robotic controller is further complicated by the dynamic nature of the human response. This paper consequently highlights the development of an appropriate set of behaviour-based control for robot-to-human object handover by first understanding an equivalent human–human handover. The optimized hybrid position and impedance control was implemented to ensure good stability, adaptability and comfort of the robot in the object handover tasks. Moreover, a questionnaire technique was employed to gather information from the participants concerning their evaluations of the developed control system. The results demonstrate that the quantitative measurement of performance of the human-inspired control strategy can be considered acceptable for seamless human–robot handovers. This also provided significant satisfaction with the overall control performance in the robotic control system, in which the robot can dexterously pass the object to the receiver in a timely and natural manner without the risk of harm or injury by the robot. Furthermore, the survey responses were in agreement with the parallel test outcomes, demonstrating significant satisfaction with the overall performance of the robot–human interaction, as measured by an average rating of 4.20 on a five-point scale.

Macroporous smart gel based on pH-sensitive polyacrylic polymer for the development of large size artificial muscle with linear contraction

Soft Matter ◽  
2021 ◽  
Author(s):  
Vincent Mansard
Keyword(s):  
Soft Matter ◽  
Artificial Muscle ◽  
Ph Sensitive ◽  
Artificial Muscles ◽  
Linear Contraction ◽  
Large Size ◽  
Polyacrylic Polymer ◽  
The Revolution

The physics of soft matter can contribute to the revolution in robotics and medical prostheses.These two fields requires the development of artificial muscles with behavior close to the biologicalmuscle. Today,...

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.

Evaluation of a Fuzzy-Based Impedance Control Strategy on a Powered Lower Exoskeleton

2015 ◽  
Vol 8 (1) ◽  
pp. 103-123 ◽  
Author(s):  
Huu Toan Tran ◽  
Hong Cheng ◽  
Huang Rui ◽  
XiChuan Lin ◽  
Mien Ka Duong ◽  
...  
Keyword(s):  
Control Strategy ◽  
Impedance Control ◽  
Lower Exoskeleton
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