Research On Coarse Tracking Control Strategy For Quantum Communication Ground Station

In the satellite-ground quantum optical communication process,the excellent tracking accuracy and stability of the ground station tracking system are the guarantee of stable and reliable communication,especially the coarse tracking servo system plays a decisive role.In this subject,a certain type of quantum satellite ground receiving station is taken as the research object.In order to improve the tracking accuracy and speed stability of the ground station system,the key technologies of coarse tracking are studied.First,according to the design index of the ground station,the ATP tracking control system of the ground station was designed,and the composition and function of each module of the ground station ATP tracking system were introduced.The coarse tracking servo system is designed in detail.The software development scheme of the upper computer and lower computer is designed,and the key algorithms are introduced.Second,a three-closed-loop control system is designed based on the vector control principle of the permanent magnet synchronous motor.The PI control is used in the current loop,and the PI controller parameters are determined by using the damping ratio of the standard second-order system.The PI controller parameters are determined by the minimum resonance peak method in the speed loop,and the resonance of the mechanical system is eliminated by using a band-rejection filter.The position loop uses a P controller to adjust the position error.In order to eliminate the static difference caused by the P controller,a speed feedforward controller is designed.Then,the perturbation suppression strategies are studied.Aiming at the fluctuation torque,the relationship between the fluctuation torque and the position is analyzed using the dynamic error coefficient method,and a feedback compensator is designed according to the expression of the fluctuation torque.The experimental results show that the compensation strategy can effectively reduce the position fluctuation.Aiming at the friction torque,the correspondence between friction torque and speed was obtained through multiple sets of experiments.A modified Lu Gre friction model was proposed,and a compensation strategy based on the improved friction model was designed.The friction compensation experiments show that the strategy can effectively suppress the nonlinear friction disturbance.For further optimization,the shortcomings of conventional PI controllers were analyzed through simulation.The speed loop PI control was optimized as a single neuron PI controller with adaptive function.The experimental results show that the optimized controller has better performance than conventional PI control.Control accuracy and robustness.Finally,the rough tracking servo system after compensation and optimization was tested in practice.When running at a constant speed and sinusoidally at different speeds,the rough tracking accuracy is better than 5 ″,which meets the design requirements.It also explains the two The effectiveness of this compensation method and speed loop optimization strategy is applicable to other low-speed servo systems.