Robust adaptive control of a 3-axis motion simulator for instruments testing

In this paper, a 3-axis motion simulator is proposed to provide a laboratory environment for testing spacecraft instruments. A mathematical model of the simulator mechanical structure is developed by means of calculating angular momentum of each rotating part with respect to relevant reference frames. Motion simulator actuators are permanent magnet synchronous motor (PMSM) drives. A compact mathematical model of the whole electromechanical system is obtained by representing the PMSM drives in their field orientation. By using Lyapunov stability theory and linearization techniques, a novel robust adaptive nonlinear control law, which is not only adaptable to constant unknown parameters but also robust to unknown but bounded fast varying disturbances, is developed for the tracking task of this PMSM direct driven system. The efficiency and correctness of the proposed control system are verified by simulation and experimental results.