Tracking control of spacecraft formation flying using Fuzzy sliding mode control with adaptive tuning technique

The present paper considers the problem of relative motion control for spacecraft formation flying. Using Fuzzy sliding mode control (FSMC) technique, a relative position/velocity tracking control based on the non-linear model is developed. The reference trajectory is generated by the force-free linearized equations of the relative motion (known as Hill´s equations) [1]. The fuzzy parameters associated with the FSMC are estimated using an adaptive algorithm derived using Lyapunov stability theory. The adaptive FSMC thus proposed is intended to compensate for the modeling uncertainties existing in practical applications. It is shown that the proposed FSMC is able to eliminate the chattering phenomenon completely as observed in conventional sliding mode control. The simulation results confirms the stability and robustness of the present scheme. A nonlinear model with additive external disturbances and bounded uncertainties is chosen for simulation studies.