FORCE/POSITION IMPEDANCE CONTROL FOR SPACE MANIPULATOR ON ORBIT CLEANING TASK OF SOLAR PANEL

The smoke generated by satellite during the process of position and attitude adjustment is easily attached to the solar panel. If the smoke is not cleaned regularly, it will lead to a decrease in the power supply capacity. Therefore, using the space manipulator to implement the task of cleaning the solar panels was studied. Firstly, the dynamic mode of the space manipulator system is established by Lagrange. Then, to control the position and attitude of the cleaning device at the end of the manipulator, the dynamic model is converted to the inertial space form based on the kinematics relationship. After, the impedance model is established according to the dynamic relationship between the position and output force of the cleaning device based on the impedance control principle to ensure stable and accurate control of the output force. In order to prevent the sudden change of the output force from damaging the solar panel due to the sudden change of the system state during the switching of each control phase of the cleaning operation, a full state constraint control strategy that the uncertain system is fitted by RBF neural network is proposed based on the barrier Lyapunov function. And on this basis, to achieve high-precision position and attitude control of the satellite and the cleaning device, the virtual control force principle is used to modify the expected trajectory of the design, so that the flexible vibration of the solar panel can be suppressed. Finally, the stability of the system is proved by the Lyapunov theorem, and the effectiveness of the proposed control strategy is verified by simulation analysis. The results show that the output force control accuracy of the cleaning device is better than 0.5 N, the position and attitude control accuracy of the satellite and the cleaning device are better than 0.1^o and 10⁻³ m.