A Study Of Servo Control Scheme With Wind Disturbance Rejection Property For Large Antenna

The study of servo control scheme with wind disturbance rejection property is an essential part of the large antenna control, which is closely related to large antenna servo control system’s control precision, stability and robustness. For large caliber antenna servo control system in the case of large wind disturbance, tracking target can produce larger pointing error. To satisfy the requirements of tracking accuracy and pointing accuracy, a PI+LQG control scheme with disturbance observer is studied to solve the problem in this thesis. The concrete application method of this control scheme is intensively studied; on this basis some engineering softwares are developed and the issues of LQG controller weight matrix setting scheme is discussed. An antenna servo experiment platform is set up to apply this control scheme. The effectiveness of this control scheme is verified by simulation and the actual system experiments. Results show that the performance of the servo system is optimized, and its capability of inhibiting of wind disturbance is markedly enhanced.The main contributions are as follows:1. Antenna modeling and wind load modeling are analyzed. Modeling of antenna speed-loop is presented for the needs of LQG controller. And the composition of antenna wind load is analyzed, based on which a modeling method of wind load as speed loop input mode is given. This wind load model proves wind disturbance signals for simulation and actual system experiments.2. For the characteristic of large antenna will produce deformation and vibration of the influence of the wind, this thesis proposes a PI+LQG controller which is designed in the modal space coordinate. The LQG modal controller estimates the modal satates with the kalman estimator, and the LQR controller control the system with the modal satates feedback. This thesis also discusses the method of LQG controller weight matrix setting scheme, baded on which a weight matrix setting GUI software is developed in Matlab. Expected control precision and wind rejection property are easily got through this GUI software.3. On account of inaccuracy caused by kalman estimation under the action of a constant value interference, disturbance observer is added in the PI+LQG controller to observe and compensate wind noise. The structure of the disturbance observer and Q filter design method are introduced in detail. By simulating on the Matlab/Simulink platform, the servo control scheme proposed in this thesis is proved to be more efficient than PI controller.4. An antenna servo experiment platform is developed, on which the control scheme proposed in this thesis is verified to be effective. The composition of experimental platform and related softwares are introduced in detail. Testing experiments are performed on the platform, and the experimental results show that this control theme significantly improves the ability to resist the wind disturbance and tracking precision of servo system.Through the study of the above content, this thesis proposes a feasible control scheme for the servo system of large antennas, which lays a certain foundation for the further development of this subject.