Robust Stabilization and Active Vibration Control of a Rigid-Flexible Multibody System Using Time-Varying Sliding Mode Algorithm

This paper proposes robust hybrid sliding mode control with a time-varying sliding surface and active vibration control for a flexible spacecraft during attitude maneuver. The fully coupled nonlinear dynamic model of the rigid-flexible system includes the three-axis rotation of the rigid body in interaction with the transverse deformation of the smart PZT-mounted flexible appendages. The smooth control signal includes a hyperbolic tangent and a sharpness function to reduce the effects of chattering and high-frequency interactions of the flexible parts and external disturbances in interaction with the rigid body and controller. The structure of the variable sliding surface with time has made it possible to adjust the effect of attitude parameters (quaternions and angular velocities) on the control performance. Also, the residual vibrations during and after the reaching phase are suppressed using a robust active vibration control algorithm. The simulations in the form of a comparative study show the performance and superiority of the proposed approach compared to conventional sliding mode control approaches for systems with structural flexibility in the presence of external perturbations and uncertainties.