Robust attitude control design for spacecraft under assigned velocity and control constraints

Abstract

A novel feedback controller under the constraints of assigned velocity and actuator control is investigated for attitude stabilization of a rigid spacecraft. More specifically, a robust nonlinear controller is firstly developed by explicitly taking into account the constraints on individual angular velocity components in the presence of external disturbances, and the associated stability proof is constructed and accomplished by the development of a novel Lyapunov function. Considering further actuator misalignments as well as the torque magnitude deviation, a modified robust least squares based control allocation is employed, in which the focus of the control allocation is to find the optimal control vector of actuators by minimizing the worst-case residual error using programming algorithms, under the condition of the uncertainties mentioned and control constraints such as actuator saturation. Finally, numerical simulation results for a rigid spacecraft model show good performance which validates the effectiveness and feasibility of the proposed scheme. © Springer-Verlag Berlin Heidelberg 2012.