Research On Servo Control System Of Gyro Stabilized And Opto-Electronic Tracking Platform

The gyro stabilized and tracking platform has developed rapidly and has been used widely in the military area and civil area such as missile seeker, airborne opto-electronic(O-E) reconnaissance, fire protection, surveillance and control of environment etc. In order to improve line of sight(LOS) stabilization precision of the opto-electronic tracking device and pinpoint the maneuvering target, we do some researches about the essential technologies in the opto-electronic automatic target tracking system. These technologies include simulation turntable design, LOS stabilized control, fiber optic gyro(FOG) signal analysis and processing, target state filtering and prediction, and tracking control methods et al. The principal contributions of this dissertation are summed as follows:1 A set of new-style four-axis precision stabilized tracking turntable, which is comprised of a two-axis vibrate turntable and a two-axis payload stabilized platform, has been developed for simulating attitude motions of TV missile seeker and airborne opto-electronic tracking system. The vibrate turntable used to simulate carrier's motions, is a two-degree-of-freedom (2DOF) instability gimbal. While, the payload platform is a 2DOF stabilized gimbal simulating azimuth and pitch attitude. The gimbal was driven directly by DC torque motor without middle driver. A compound cascade control structure based on DSP module using the charge coupled device(CCD) camera or O-E encoder to constitute the position closed-loop, and using the FOG to constitute the rate stabilization closed-loop is put forward. Testing results achieve the technical indices and precision requirement.2 The properties of the FOG signal random drift are detected with the Allan variance method. By the relation between the Allan variance of signal noise and power spectrum density (PSD), the sources of some kinds of noise and its properties are analyzed and calculated using fitting algorithm in the least square method(LSM). According to the characteristics of the gyro stabilized platform system, the moving filter, the forward linear prediction(FLP) adaptive filter and the threshold-value filter based on wavelet transform are used to de-noise the FOG signal. The result of testing and statistic analyzing for FOG signal indicate that the Allan variance means is successful in separating the main random error source of signal noise and the advantages of the wavelet threshold-value filter is verified.3 Considering the shortcomings of single rate-loop servo control composed of rate gyro for LOS stabilization of opto-electronic tracking system, a dual rate-loop cascade control structure using the DC tachometer to constitute the analog inner loop, and using the rate gyro to constitute the digital outer loop is presented. The functions of rejecting friction disturbance and insulating carrier turbulence are designed respectively. The system performance for disturbances rejection and robustness are analyzed and compared with single rate-loop servo...