Robust super-twisting sliding mode controller with state observer for position tracking of ionic polymer–metal composite actuators

Abstract

To date, a novel class of smart materials, known as ionic polymer–metal composites, have been intensively studied because of their huge potential applications in robotics, microelectromechanical systems, biomedical devices, and artificial muscles. The position tracking control of the ionic polymer–metal composite actuators is one of the challenging tasks due to the highly nonlinear, uncertain, and unmodeled dynamics. These inaccurate and unmodeled dynamics cause the unwanted disturbances which reduce the control performance. Therefore, a robust feedback controller for position tracking of the ionic polymer–metal composite actuators is necessary. To address this issue, this article presents a super-twisting sliding mode controller combined with integral-chain differentiator as state observer. The main advantage of the proposed method is its potential to estimate the states of the system continuously. As a result, the controller not only eliminates the parameter uncertainties and external disturbance but also it can overcome the chattering problem. The results confirm the feasibility and efficiency of the proposed method both in simulation and experiment.

Design of an integral super twisting sliding mode controller for position control and extending the traveling range of initially curved micro-beams

“…The above switching control law is known as the super twisting algorithm and η 1 and η 2 are control gains. The super twisting algorithm is able to generate continuous control signal and warrants finite-time convergence (Kolahi and Moeinkhah, 2020; Moreno and Osorio, 2008; Sami et al, 2020). Hence, the total auxiliary control input u r is expressed as followsThe remaining task is to design a disturbance observer, so the unknown disturbance D could be replaced with its estimation D e .…”

Adaptive disturbance observer-based improved super-twisting sliding mode control for electromagnetic direct-drive pump

“…The steady-state accuracy is further improved while reducing the jitter [22]. The researchers proposed a super-twisting sliding mode controller combined with an integral-chain differentiator as a state observer to estimate the parameter uncertainties and external disturbance [23]. Nevertheless, considering the linear sliding mode surface can only achieve asymptotic stability.…”