Fuzzy sliding mode control for shock absorber of flexible spacecraft on-orbit separation

In order to reduce the influence of the impact load during the on-orbit separation, a Magneto-rheological (MR) shock absorber was used. The configuration of shock absorber was also introduced. Flexible spacecraft dynamic model with large reference displacement was established based on finite element and Lagrange method, and sliding mode was used to control the output of the MR shock absorber. A new two dimensional fuzzy sliding mode control was proposed to control the reaching coefficient of the reaching law to improve the dynamic characteristics of the MR shock absorber. Numerical simulation results show that MR shock absorber controlled by the proposed method obviously decreases the impact influence and reduces the chattering. The coupling of the base and flexible appendages is weakened, and velocity and acceleration of the flexible appendages become smoother. Furthermore, the proposed method has a better steady value and tracking characteristic compared with traditional sliding mode control.