Model-Based Nonlinear Control of the Dielectric Elastomer Actuator With High Robustness and Precision

2019 ◽  
Vol 86 (12) ◽  
Author(s):  
Mingqi Zhang ◽  
Xunuo Cao ◽  
Xiangping Chen ◽  
Zhen Zhang ◽  
Zheng Chen ◽  
...  
Keyword(s):  
Feedback Control ◽  
Nonlinear Model ◽  
Control Strategy ◽  
Electromechanical Coupling ◽  
Tracking Error ◽  
Soft Robots ◽  
Practical Applications ◽  
Flexible Devices ◽  
Model Based ◽  
Modeling Uncertainties

Abstract Dielectric elastomers (DEs) is one of the promising artificial muscle for soft robots and flexible devices. As one of the key issues for practical applications, the control of DE actuators remains challenging due to the large actuation, electromechanical coupling, and viscoelastic dissipation. Feedforward control and proportional integral derivative (PID) feedback control are recently studied for the control of DE actuators. The control performance is still limited due to the complex dynamic behavior of DE actuators with both nonlinearities and modeling uncertainties. This paper proposes a model-based feedback control for DE actuator, considering nonlinearity of large deformation, electromechanical coupling, and the modeling uncertainties. A nonlinear motion model is proposed and verified by parameter identification experiments. Based on the nonlinear model, we demonstrate a robust control strategy including nonlinear model compensation and robust feedback to decrease the tracking error. The experimental results verify that the control strategy possesses excellent validity to the DE actuator with improved performance compared to the previous strategy of feedforward and PID feedback control. The system design and control strategy of this paper may guide the future design and application of DE actuators, soft robots, and flexible devices.

Electromechanical model-based adaptive control of multilayered dielectric elastomer bending actuator

2021 ◽  
pp. 1-26
Author(s):  
Fanghao Zhou ◽  
Jin He ◽  
Mingqi Zhang ◽  
Youhua Xiao ◽  
Chen Zheng ◽  
...  
Keyword(s):  
Large Deformation ◽  
Control Strategy ◽  
Low Voltage ◽  
Dynamic Control ◽  
Fast Response ◽  
Dielectric Elastomer ◽  
Parameter Uncertainties ◽  
Soft Robots ◽  
Model Based ◽  
Bending Actuator

Abstract Dielectric elastomer (DE) possesses attributes such as large deformation and fast response. As a typical DE actuating structure, the multilayered DE bending actuator (MDEBA) is lightweight, and can actuate in relatively low voltage without a rigid frame and pre-stretch. These attributes arouse wide research interest in the MDEBA on the application of soft robots. However, due to its large deformation and nonlinear electromechanical dynamics, the control of MDEBA remains highly challenged. Considering the large bending deformation and gravity effect, we develop an electromechanical dynamic model-based control strategy, which can adaptively compensate for the parameter uncertainties during the actuation of MDEBA. Experimental results validate that this control strategy provides highly enhanced control performances compared to the PID controller. The electromechanical modeling method and dynamic control strategy may guide the further study of MDEBA, soft robots, and flexible devices.

Insect-scale fast moving and ultrarobust soft robot

2019 ◽  
Vol 4 (32) ◽  
pp. eaax1594 ◽  
Author(s):  
Yichuan Wu ◽  
Justin K. Yim ◽  
Jiaming Liang ◽  
Zhichun Shao ◽  
Mingjing Qi ◽  
...  
Keyword(s):  
Polymeric Materials ◽  
Driving Mechanism ◽  
Soft Robot ◽  
Operating Characteristics ◽  
Soft Robots ◽  
Practical Applications ◽  
Flexible Devices ◽  
Amplitude Vibration ◽  
Piezoelectric Structure ◽  
Large Amplitude Vibration

Mobility and robustness are two important features for practical applications of robots. Soft robots made of polymeric materials have the potential to achieve both attributes simultaneously. Inspired by nature, this research presents soft robots based on a curved unimorph piezoelectric structure whose relative speed of 20 body lengths per second is the fastest measured among published artificial insect-scale robots. The soft robot uses several principles of animal locomotion, can carry loads, climb slopes, and has the sturdiness of cockroaches. After withstanding the weight of an adult footstep, which is about 1 million times heavier than that of the robot, the system survived and continued to move afterward. The relatively fast locomotion and robustness are attributed to the curved unimorph piezoelectric structure with large amplitude vibration, which advances beyond other methods. The design principle, driving mechanism, and operating characteristics can be further optimized and extended for improved performances, as well as used for other flexible devices.

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