scholarly journals The Design and Mathematical Model of a Novel Variable Stiffness Extensor-Contractor Pneumatic Artificial Muscle

Soft Robotics ◽  
2018 ◽  
Vol 5 (5) ◽  
pp. 576-591 ◽  
Author(s):  
Hassanin Al-Fahaam ◽  
Samia Nefti-Meziani ◽  
Theo Theodoridis ◽  
Steve Davis
Keyword(s):  
Mathematical Model ◽  
Artificial Muscle ◽  
Variable Stiffness ◽  
Pneumatic Artificial Muscle

scholarly journals Novel Design and Modeling of a Soft Pneumatic Actuator Based on Antagonism Mechanism

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 107
Author(s):  
Yinglong Chen ◽  
Junhao Zhang ◽  
Yongjun Gong
Keyword(s):  
Mechanical Characteristics ◽  
Artificial Muscle ◽  
Variable Stiffness ◽  
Pneumatic Artificial Muscle ◽  
Human Machine Interaction ◽  
Soft Actuator ◽  
Stiffness Characteristics ◽  
Machine Interaction ◽  
Novel Design ◽  
Compound Action

The soft actuator possesses the characteristics of flexibility, environmental adaptability, and human–machine interaction. Firstly, aiming to resolve the limitation of variable stiffness performance of a traditional pneumatic artificial muscle (PAM) actuator, based on the antagonistic mechanism of extensor and contractor muscles, a novel pneumatic soft actuator coupled of extensor and contractor muscles is proposed in this paper. The actuator can perform the compound action of elongation/contraction, and the stiffness of it can be controlled by adjusting the elongation and contraction forces. Secondly, based on the deformation principle of woven and elastic fabric layers, the mechanical characteristics model of the actuator is established and simulated. The mechanical properties of the actuator are tested under different pressures and deformation displacement and the variable stiffness characteristics of the actuator are verified. Finally, actuators are utilized to manufacture a soft mechanical manipulator, which can achieve variable stiffness in a fixed bending attitude.

A Pneumatic Artificial Muscle Bionic Kangaroo Leg Suspension

2019 ◽  
Vol 12 (4) ◽  
pp. 357-366
Author(s):  
Yong Song ◽  
Shichuang Liu ◽  
Jiangxuan Che ◽  
Jinyi Lian ◽  
Zhanlong Li ◽  
...  
Keyword(s):  
Strong Shock ◽  
Artificial Muscle ◽  
Suspension System ◽  
Vehicle Body ◽  
Vehicle Suspension ◽  
Pneumatic Artificial Muscle ◽  
Advantages And Disadvantages ◽  
Road Excitation ◽  
Vehicle Suspension System ◽  
Suspension Structure

Background: Vehicles generally travel on different road conditions, and withstand strong shock and vibration. In order to reduce or isolate the strong shock and vibration, it is necessary to propose and develop a high-performance vehicle suspension system. Objective: This study aims to report a pneumatic artificial muscle bionic kangaroo leg suspension to improve the comfort performance of vehicle suspension system. Methods: In summarizing the existing vehicle suspension systems and analyzing their advantages and disadvantages, this paper introduces a new patent of vehicle suspension system based on the excellent damping and buffering performance of kangaroo leg, A Pneumatic Artificial Muscle Bionic Kangaroo Leg Suspension. According to the biomimetic principle, the pneumatic artificial muscles bionic kangaroo leg suspension with equal bone ratio is constructed on the basis of the kangaroo leg crural index, and two working modes (passive and active modes) are designed for the suspension. Moreover, the working principle of the suspension system is introduced, and the rod system equations for the suspension structure are built up. The characteristic simulation model of this bionic suspension is established in Adams, and the vertical performance is analysed. Results: It is found that the largest deformation happens in the bionic heel spring and the largest angle change occurs in the bionic ankle joint under impulse road excitation, which is similar to the dynamic characteristics of kangaroo leg. Furthermore, the dynamic displacement and the acceleration of the vehicle body are both sharply reduced. Conclusion: The simulation results show that the comfort performance of this bionic suspension is excellent under the impulse road excitation, which indicates the bionic suspension structure is feasible and reasonable to be applied to vehicle suspensions.

scholarly journals Development of an Exoskeleton-Type Assist Suit Utilizing Variable Stiffness Control Devices Based on Human Joint Characteristics

Actuators ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Seigo Kimura ◽  
Ryuji Suzuki ◽  
Katsuki Machida ◽  
Masashi Kashima ◽  
Manabu Okui ◽  
...  
Keyword(s):  
Joint Stiffness ◽  
Knee Extensor ◽  
Artificial Muscle ◽  
Variable Stiffness ◽  
Lower Limbs ◽  
Joint Characteristics ◽  
Standing Up ◽  
Maximum Decrease ◽  
Control Devices ◽  
The Relationship

In this paper, the prototype of the assistive suit for lower limbs was developed. The prototype was based on an assist method with joint stiffness and antagonized angle control. The assist method comprises a system consisting of a pneumatic artificial muscle and a pull spring, which changes the joint stiffness and the antagonized angle to correspond to the movement phase and aims at coordinated motion assistance with the wearer. First, the characteristics of the developed prototype were tested. It was confirmed that the measured value of the prototype followed the target value in the relationship between torque and angle. In addition, there was hysteresis in the measured value, but it did not affect the assist. Next, the evaluation of standing-up and gait assist by measuring electromyography (EMG) of the knee extensor muscle was conducted using the prototype. In all subjects, a decrease in EMG due to the assist was confirmed. In one subject, the maximum decrease rate at the peak of the EMG was about 50% for standing-up motion and about 75% for gait motion. From the results of these assist evaluations, the effectiveness of the assist method based on the joint stiffness and antagonistic angle control using the prototype was confirmed.

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