IJCAS

The development of compliant actuators has garnered tremendous interest in recent years, particularly for their ability to simplify a torque control problem into a deformation position control problem. In order to ameliorate torque control of compliant actuators subject to unknown external disturbances and model parameter uncertainties, a robust composite control strategy is proposed in this article. Firstly, an extended state observer is employed to estimate the lumped disturbance, and a continuous control law is achieved by adopting continuous sliding mode control. Then, the switching gain is only required to exceed the upper bound of the estimation error. Furthermore, by introducing prescribed performance control technology, a novel sliding surface based on transformed error and disturbance estimation is designed, which guarantees rapid global convergence, superior transient performance, strong robustness, and minimal chattering. The closed-loop system stability is rigorously proven using the Lyapunov method. Finally, the simulation and experimental results validate the effectiveness of the proposed control strategy.

Keywords: Chattering suppression, compliant actuator, extended state observer, prescribed performance control, sliding mode control.