Sliding mode controller for Sawyer motors based on singular perturbation theory

In this paper, we propose a sliding mode controller (SMC) based on singular perturbation theory for Sawyer motors. Since the dynamics of Sawyer motors can be divided into slow and fast subsystem, the current measurements are removed by using singular perturbation theory and passivity of the dynamics of Sawyer motors. Input voltages including auxiliary inputs for slow subsystem are designed to stabilize the fast dynamics. The quasi-steady states of fast subsystem, which become the inputs of reduced model corresponding to slow subsystem, is a function of the auxiliary inputs. We design the auxiliary inputs with SMC to stabilize the reduced model. Therefore, the output feedback position controller for Sawyer motors can be achieved by the proposed method. The effectiveness of proposed method is demonstrated by simulation results.