Composite control and error suppression for space opto-electronic tracking turntable considering friction characteristic compensation

Space opto-electronic turntables are increasingly utilized in space situational awareness missions and high-speed laser communication. However, during full-range maneuvers, these turntables experience significant nonlinear friction forces due to the axis system and friction generated by the conductive ring. These friction forces exhibit drastic changes when the speed exceeds zero, resulting in error spikes. Additionally, the turntable has a structural characteristic of large inertia, which contributes to lagging tracking errors. In order to suppress the tracking error and improve the dynamic performance of the space opto-electronic turntable, this paper proposes a composite control strategy that integrates friction characteristic observation and compensation with position feedforward. The model of friction load such as conductive rings is identified and observed, and the friction torque is reconstructed and compensated by the LuGre model. Furthermore, a composite feedforward control is implemented to mitigate the tracking hysteresis error. The effectiveness of the proposed method is verified through simulation and experimentation. The results demonstrate that the composite control method integrated friction characteristic observation and compensation with position feedforward significantly improves the control bandwidth and obviously reduces the tracking error of the opto-electronic turntable servo system. This innovative control strategy not only advances the performance of opto-electronic turntables but also holds significant implications for the design of other high-performance pointing and tracking servo systems in various applications.