Adaptive Variable Impedance Control for Force Sensor-less Joysticks

A lightweight and compact two-degree-of-freedom joystick was designed herein, and an adaptive variable impedance control strategy of sensor-less was proposed based on the joysticks. Firstly, the impedance parameters were adjusted according to the control forces of the operators to adapt to the different control habits of the operators. Secondly, in addition to ensuring accurate position control, the velocity control at the end-effector of the joystick was also added to improve the operator's control experience. Then, based on the variable impedance compliance control, the teleoperation force estimation control strategies were added to avoid the increase in system complexity caused by the extra wiring of the force sensor and the corresponding measurement noises. The stability of the above control strategies was proved in the Lyapunov sense, which shows that the control errors arc convergent and the responses of the whole closed-loop system are uniform ultimate boundedness(UUB). Finally, the validity and stability of the above strategies were verified by simulation experiments and actual bench experiments. © 2024 Chinese Mechanical Engineering Society. All rights reserved.