Attitude and Vibration Control of a Flexible Spacecraft using Fuzzy and High-Order Sliding Mode Algorithms

This paper develops an intelligent attitude control and vibration suppression system for flexible spacecraft performing a single-axis maneuver with external disturbances and parameter uncertainties. Fully coupled nonlinear equations of motion are discretized by Hamilton's principle and the finite element method. The attitude control structure utilizes a fuzzy algorithm to control the attitude and vibration of the panel simultaneously. This algorithm uses a vibration criterion for flexible parts, attitude errors and time inputs. In order to evaluate the performance of such an approach, super twisting-non-singular terminal sliding mode (SNTSMC) and strain rate feedback (SRF) were used simultaneously. The proposed SNTSMC/SRF algorithm takes advantage of each as part of a hybrid algorithm that leads to increased targeting accuracy, faster convergence rate, reduced chattering, reduced residual vibrations, and reduced rigid-flexible bodies interactions. The Lyapunov theory demonstrates the system's overall stability. Simulation results as a comparative study demonstrate the effectiveness of both approaches in reducing control-structure interactions during large-angle maneuvers.