Research On Vehicle Tracking And Pointing Turntable Servo System Based On High-precision Identification

With the rapid development of laser communication,target tracking and other fields,the application of photoelectric tracking equipment has become more and more extensive.The vehicle photoelectric equipment with high mobility has become a research hotspot.As the core part of vehicle photoelectric tracking system,tracking turntable needs to overcome the disturbance of the vehicle body vibration and wind resistance to achieve high-precision and stable tracking of the target,which puts forward higher requirements for the performance of servo control system.High precision control requires advanced servo control strategy and accurate transfer function model.In this paper,the servo control system of vehicle photoelectric tracking and pointing turntable is designed and studied from two aspects of system identification technology and servo control technology based on the vehicle laser communication,Design a reasonable structure according to the technical indicators of the tracking and pointing turntable,the working principle of the vehicle tracking and pointing system is introduced.The principle of LOS stability is analyzed.The composition and principle of the servo control system are described.The main components of the tracking and pointing turntable are analyzed and selected.The servo controller of"ARM processor+FPGA data acquisition+H-bridge drive"is designed.Aiming at the system transfer function identification problem,an adaptive differential evolution identification method is designed by improving the mutation factor and crossover probability,and the standard test function is used to verify that the speed and accuracy of the identification algorithm for parameter solving are better than GA,PSO,and DE algorithms.Perform modeling analysis on the main units of the turntable,and conduct frequency response tests to identify the accurate transfer function model of the tracking and pointing turntable.In order to improve the anti-interference ability and tracking accuracy of the vehicle tracking and pointing turntable,the speed loop and position loop of the control system are designed based on the obtained control system transfer function model,and the angular velocity measured by the gyro is introduced into the input end of the speed loop through the LOS stability equation.the speed feedforward control based on measurable disturbance is designed,and at the same time,the extended state observer(ESO)of active disturbance rejection control(ADRC)technology is added to the position loop,and the output of the position loop is adjusted by the estimated disturbance value of ESO to realize the compensation of unknown disturbance of the turntable.The simulation results verify the effectiveness of speed feedforward and ESO for disturbance suppression and compensation.The control algorithm is actually tested on the vehicle photoelectric tracking and pointing turntable.The turntable tracks a target moving at a constant speed of 1°/s under the disturbance of a simulated carrier with an angular velocity of 10°/s and an angular acceleration of 10°/s~2.After stabilization,the dynamic tracking accuracy is less than 57μrad.A wireless laser communication test is established between two optical transceivers at a distance of 1km.Under the same disturbance,the steady-state tracking accuracy is less than85μrad,and the communication link is stable,which is better than the design index of the turntable.