Research On Servo Control Problems Of Remote Control Weapon Station

The remote weapon station is a weapon system that combines situational awareness,target search and firepower,and plays an increasingly important role in modern warfare.The motion performance of the weapon station servo mechanism has an important impact on the target aiming and firing accuracy of the weapon station.Therefore,this paper focuses on the improvement of the motion performance of the weapon station servo mechanism,from dynamic modeling,sensor signal processing,trajectory command planning,nonlinear friction compensation and algorithm rapid prototyping.And a high performance motion control strategy that effectively improves low speed performance and stability is presented.The main work of the thesis is as follows:1.The main components of the servo station of the remote weapon station,namely the driving part,the structure part and the sensor part,are analyzed in detail,and an electromechanical coupling model which can effectively describe the dynamic behavior of the weapon station servo mechanism is constructed.Through the combination of theoretical analysis and simulation,the influence of main parameters of the mechanism on low-speed performance,stability accuracy,positioning accuracy and maximum speed is analyzed.The results show that for the servo station servo mechanism with RV transmission system,the driving power,transmission friction,transmission backlash and sensor noise have the most significant impact on servo performance.2.Aiming at the nonlinear factors in the servo mechanism that affect the stability accuracy and the smoothness of low-speed motion,the friction friction modeling and compensation research of the transmission mechanism(RV transmission system)of the weapon station is carried out.The proposed friction model is divided into two parts: a pre-sliding zone and a sliding zone.In the pre-sliding zone,the elastic deformation recovery characteristics of the RV transmission system are obtained by performing the loading-unloading experiment on the RV transmission system in the torque mode.Based on this feature,the pre-sliding friction-displacement function relationship(spring model)is constructed,and thus the problem that the traditional pre-sliding friction model fails due to the low speed resolution is solved.In the sliding zone,based on the traditional Stribeck friction model,the relationship between friction and angular position is investigated.By subdividing the angular position,the corresponding relationship between sliding friction,angular position and angular velocity is obtained.And the problem of inconsistent friction at different angular positions at the same rotational speed due to assembly error and unbalanced torque is solved.3.In order to obtain speed with high signal-to-noise ratio,high real-time and satisfactory accuracy from the encoder differential signals,and to observe and compensate the disturbance torque of the servo mechanism,a state extended Kalman filter(SAKF)composed control strategy is proposed.This control strategy is used in the speed loop and consists of three parts: SAKF module,feedforward controller and feedback controller,where the SAKF module is used for speed observation and disturbance compensation,feedforward controller is used to improve the control bandwidth and feedback controller is used to correct speed error.The principle,design,implementation and parameter setting method of the control strategy are given in detail,and the experimental verification is carried out.Experimental results show that the control method can improve the stability accuracy by 40% and the low-speed motion performance by 88%.4.Reasonable planning of the trajectory commands in the position mode is a necessary measure to improve the smoothness of the servo mechanism.How to ensure the smoothness of the mechanism while taking into account the rapidity,so that the weapon station servo mechanism always meets the dynamic constraints during the movement process,which is an important problem to be solved in the trajectory planning.In this paper,several typical forms of S-curve trajectory planning algorithm are summarized,and the general expression of S-curve trajectory planning algorithm is obtained.Combined with the speed constraints,power constraints and torque constraint equations of the actual system,a S-curve trajectory planning parameter tuning method based on dynamic constraints is proposed to ensure the smoothness and rapidity of motion.Further,considering the problem that the positioning accuracy is reduced due to discretization in the implementation process,the secondary correction method for rounding the parameters is adopted,thereby ensuring the flexibility,rapidity and positioning accuracy of the motion process.5.The motion control algorithm of the weapon station servo mechanism involves many factors and the algorithm structure is complex.Therefore,it takes a long time to manually write the algorithm program,and the code debugging is difficult.In order to solve this problem,this paper uses the rapid prototyping method to design and test the algorithm.Simulink is used to graphically design different control algorithm units,and the rationality of the algorithm,the feasibility of the algorithm,and the effectiveness of the target code are tested by software-in-loop,hardware-in-loop and physical debugging.Then the product-level algorithm was obtained,which effectively shortened the control algorithm development cycle.