Position and stiffness control of an antagonistic variable stiffness actuator with input delay using super-twisting sliding mode control

Motor dynamics in antagonistic variable stiffness actuator (AVSA) is generally disregarded control system design. This ignorance can lead to an inaccurate model, affecting the performance of closed-loop system. The motor be modeled as input-delay model. In this paper, input time-delay for AVSA first time. a nonlinear function states; thus, tracking challenging task. Specifically, many existing delay compensation controllers cannot used when model contains delay. To handle issue, transformation introduced and super-twisting sliding mode then utilized reach position simultaneously. Prediction-based feedback involved together with some disturbance observers estimating external compensate time-delay. Simulation results show that proposed design approach successful simultaneously attenuating effect.