Research On Servo Control System Of Gyro-Stabilized Platform

Gyro-stabilized platform can isolate the disturbance of carrier to keep the line-of-sight of exploring equipment stable in the inertial space, which is sure that exploring equipment can trace to targets accurately, so gyro-stabilized platform have great application in the modern weapon system. According to the needs of the project, this paper studied the operation principle of gyro-stabilized platform system, built mathematic model of the system, deeply studied friction moment and gyro noise which are main influencing factors of system precision, analyzed and studied the solving methods of the two questions.At first, based on understanding the operation principle of gyro-stabilized platform system, this paper built the model of each part of the system, perfected the model based on the transmission mechanics of the disturbance of carrier.Nonlinear friction have great influence on system precision, so this paper built friction model that is appropriate for simulation, which have great sense on studying the influence of disturbance and the control effect of controllers.Then, the noise of gyro is another main influencing factor of system precision. This paper used Allan variance method which is IEEE well-known standard method of the analyses of gyro parameter to analyze gyro signal noise. This paper studied three filtering methods: digital low-pass filter; wavelet threshold-value filter; self-adaptation filter, and used the three methods to deal with the gyro signal, compared the effect of filtering by simulation. Besides, this paper analyzed amplitude-frequency spectrum (AFS) of gyro signal before and after filtering, obtained the amplitude of various error sources in gyro signal by using the Allan variance method and the least square fitting procedure, then from different aspects verified that the filter effect of self-adaptation filter is the best in the three filter methods.At last, this paper built the controller of the platform servo-system, mainly studied classical lead-lag control and variable structure control (VSC). The control effect of the two controllers was analyzed and compared by simulation, and the results indicated VSC's control effect is better than lead-lag control's. Besides, this paper did the simulation experiments of system position tracing. The results indicated that the system under VSC can trace normal low-frequency objects, and meet the challenge of tracking accuracy.