scholarly journals Tracking Control of Pneumatic Artificial Muscle-Activated Robot Arm Based on Sliding-Mode Control

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 66
Author(s):  
Chih-Jer Lin ◽  
Ting-Yi Sie ◽  
Wen-Lin Chu ◽  
Her-Terng Yau ◽  
Chih-Hao Ding
Keyword(s):  
Trajectory Tracking ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Artificial Muscle ◽  
High Order ◽  
Feedback Controller ◽  
Pneumatic Artificial Muscle ◽  
Robot Arm ◽  
Circular Trajectory ◽  
External Interference

This study discusses a circular trajectory tracking function through a proposed pneumatic artificial muscle (PAM)-actuated robot manipulator. First, a dynamic model between a robot arm and a PAM cylinder is introduced. Then the parameters thereof are identified through a genetic algorithm (GA). Finally, PID is used along with a high-order sliding-mode feedback controller to perform circular trajectory tracking. As the experimental results show, the parameters of sampling time and moment of inertia are set to accomplish the trajectory tracking task in this study. In addition, the maximum error between the objective locus and the following locus was 11.3035 mm when applying theta-axis control to the circular trajectory of the robot arm with zero load or lower load. In an experiment of controller comparison, the results demonstrate that a high-order sliding-mode feedback controller is more robust in resisting external interference and the uncertainty of modeling, making the robot arm have good performance when tracking.

scholarly journals Design of Hybrid Phase Sliding Mode Control Scheme for Lower Extremity Exoskeleton

2019 ◽  
Vol 9 (18) ◽  
pp. 3754
Author(s):  
Lingling Chen ◽  
Chao Wang ◽  
Jie Wang ◽  
Xiaowei Song
Keyword(s):  
Lower Extremity ◽  
Sliding Mode Control ◽  
Sliding Mode ◽  
Artificial Muscle ◽  
Phase Changes ◽  
Working Environment ◽  
Phase Detector ◽  
Pneumatic Artificial Muscle ◽  
Mode Control ◽  
Control Scheme

Aiming at a pneumatic artificial muscle (PAM) lower extremity exoskeleton, a control mechanism based on hybrid phase sliding mode control (SMC) is proposed. First of all, the human gait cycle is mainly divided into the swing phase and stance phase, and the lower extremity exoskeleton phase models are established by the Euler–Lagrange method, respectively. Secondly, the lower limb exoskeleton is inevitably affected in the diverse working environment, and the exoskeleton model has nonlinear and strong coupling characteristics, which both increase the control difficulty. In this situations, a robust sliding mode control method is designed based on an Extended State Observer (ESO). Thirdly, the pneumatic muscle takes time to contract and relax, and then the joint input torque cannot jump when the gait phase changes, hence, the smoothing switching of the assistive control scheme is introduced to solve it. The smoothing switching time is detected by a phase detector, and the phase detector is designed by the plantar pressure information. Finally the comparative simulation shows that this control strategy has the advantages of fast time, high control precision and no jump during control torque switching. Pneumatic artificial muscle contraction rate curve shows that the pneumatic muscles’ motion range meets the control requirement of the exoskeleton.

scholarly journals The Design and Implementation of a Single-Actuator Soft Robot Arm for Lower Back Pain Reduction

2020 ◽  
Vol sceeer (3d) ◽  
pp. 25-29
Author(s):  
Alaa Al-Ibadi
Keyword(s):  
Back Pain ◽  
Lower Back Pain ◽  
Artificial Muscle ◽  
Soft Robot ◽  
Pneumatic Artificial Muscle ◽  
Robot Arm ◽  
Design And Implementation ◽  
Lower Back ◽  
The People ◽  
High Degree

This paper presents a simple and fast design and implementation for a soft robot arm. The proposed continuum arm has been built by a single self-bending contraction actuator (SBCA) with two-fingers soft gripper. Because of the valuable advantages of the pneumatic artificial muscle (PAM), this continuum arm provides a high degree of safety to individuals. The proposed soft robot arm has a bending behaviour of more 180° at 3.5 kg, while, its weight is 0.7 kg. Moreover, it is designed to assist the people by reducing the number of backbends and that leads to a decrease in the possibility of lower back pain.

scholarly journals The Control Algorithm and Experimentation of Coaxial Rotor Aircraft Trajectory Tracking Based on Backstepping Sliding Mode

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 337
Author(s):  
Jiulong Xu ◽  
Yongping Hao ◽  
Junjie Wang ◽  
Lun Li
Keyword(s):  
Sliding Mode Control ◽  
Trajectory Tracking ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Model Parameters ◽  
External Interference ◽  
Mode Control ◽  
Coaxial Rotor ◽  
Non Linear ◽  
Backstepping Sliding Mode Control

In view of the uncertainty of model parameters, the influence of external disturbances and sensor noise on the flight of coaxial rotor aircraft during autonomous flight, a robust backstepping sliding mode control algorithm for the position and attitude feedback control system is studied to solve the trajectory tracking problem of an aircraft in the case of unknown external interference. In this study, a non-linear dynamic model based on a disturbed coaxial rotor aircraft was established for an unknown flight. Then, a non-linear robust backstepping sliding mode controller was designed, which was divided into two sub-controllers: the attitude controller and the position controller of the coaxial rotor aircraft. In the controller, virtual control was introduced to construct the Lyapunov function to ensure the stability of each subsystem. The effectiveness of the proposed controller was verified through numerical simulation. Finally, the effectiveness of the backstepping sliding mode control algorithm was verified by flight experiments.

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