Model Parameter Identification And Active Disturbance Rejection Control Of Gyro-Stabilized Platform

Gyroscope stabilized platform (GSP) is the device that isolates vibration and overcomes the influence on photoelectric sensors caused by the carrier attitude changes effectively, and thus to keep the bore sight of airborne photoelectric sensor stable, and ensure the photoelectric devices driven by the operation commands track and capture the target accurately. The isolation control accuracy of gyro-stabilized platform is influenced by the un-modeled in the controlled system, random disturbance and measurement noise of the output signal. The real gyro-stabilized platform system can’t reach the expected high-level performance merely using PID controller. In order to improve the control accuracy, an integrated solution for eliminating all influenced factors is needed. The main research of the dissertation is to design an integrated solution to eliminate the three factors for the control performance to stable the platform, mainly includes the following three aspects:1) With the nonlinear friction model of the interior direction velocity loop developed by our team, genetic algorithm toolbox has been applied on the parameters identification of the twelve parameters of the velocity loop. The results of parameter identification is optimized with real-coded accelerating genetic algorithm, hybrid genetic algorithm, multiple population genetic algorithm and adaptive genetic algorithm to get the mathematic model of velocity loop.2) Considering the main factors of the control performance, a two-step control strategy which contains employing the active disturbance rejection control (ADRC) to observe and compensate the un-modeled and designing the feedback control in ADRC as PID controller to control the compensated system as the first step and using Kalman filter to eliminate the random disturbance and measurement noise as the second step is proposed. Results indicate that the isolation degree reaches 4.61% using this control strategy when the disturbance of the platform is 3 degree, 1/6Hz, which means the isolation performance improves 50.9%comparing with the performance 9.39% of the control strategy which consists of the parameter identification of nonlinear friction and its forward compensation. The control strategy evidently has a higher practical application value.3) The differences of these two control strategies on structures and design are analyzed. The simulation experiments indicate that the performance of isolation degree can reach 4.61% using ADRC, and 3.05% under the VDOB control scheme in the case that the platform disturbance is 3 degree, 1/6Hz, which means the isolation performance at least improves 50.9% comparing with the performance of 9.39% in the PID control system with the nonlinear friction parameters’identifications and the forward compensation. Comparing the two strategies, it can be found that, the ADRC is a more real time control strategy, and the VDOB control has a higher precision control for the gyro stabilized platform.