Fuzzy Sliding Mode-PID Control for Space Manipulator Using Dynamically Equivalent Manipulator Model

Abstract

In this paper, a sliding mode-PID control approach is proposed for free-floating space manipulator. Free-floating space manipulator has nonlinear dynamics and interactions between the manipulator and the spacecraft. In this paper, dynamic of space manipulator system is presented by dynamically equivalent manipulator (DEM) model. DEM is a fixedbase manipulator and its dynamics behavior under any control law is identical to dynamics behavior of space manipulator. Using sliding mode-PID control, sliding mode controller and PID controller properties are applied to the control system. In this case, high control gain leads to reduction of reaching time but increment of oscillation. Therefore fuzzy logic can be used as an intelligent approach in order to tune PID-like sliding surface gains. Simulation shows satisfactory results in tracking and error cancellation.