A Fourier series-based adaptive sliding-mode controller for nonlinear pneumatic servo systems

The behavior of nonlinearity and time-varying cause the pneumatic actuator systems are difficult to be controlled. This paper proposes a Fourier series-based adaptive sliding-mode controller for nonlinear pneumatic servo systems. The Fourier series-based functional approximation technique can approximate an unknown function, thus bypassing the model-based prerequisite. The learning laws for the coefficients of the Fourier-series functions are derived from a Lyapunov function to guarantee the system stability. Consequently, practical experiments on a rodless pneumatic servo system are successfully implemented with different path tracking profiles, which validates the proposed method.