Design And Research Of Servo Control System Of Two-axis & Four-gimbal Platform

The stabilization and tracking platform is a kind of servo platform mounted on the moving vehicle. The gyroscope is used to sense the velocity disturbance of vehicle.When vehilce moves, the platform framework can be adjusted constantly to guarantee the stability of detection equipment in inertial space.It has been widely applied in military and civil field with the function of target searching and tracking. In the view of the background of project and the function requirements, the research of this paper is associated with a two-axis four-gimbal stabilization and tracking platform servo control system. The research is operated to design the control loop of each operating mode, control theory of stabilization and the hardware and software of servo control system.The main research of this paper include the following aspects.According to the functional requirements, scheme design of the two-axis four-gimbal platform servo control system is completed, including the structure of control system, the selection of main components, the mathematical model of platform, the analysis of operation mode and control loop structure and the principle of stability.The hardware circuit of servo control system is designed based on the project requirements. Schematic diagrams and PCB boards are designed and debugged according to their own functions.The software program is also designed. The design of correction elements in position control loop and corresponding experimental works are completed in the physical two-axis four-gimbal platform, which has achieved the desired performance.In the aspect of stabilization control strategy, based on classical control method, the signal of gyroscope of inner frame is introduced into the outer gimbal to improve the dynamic performance. The PI control method is used to design the controllers of each control loops of inner and outer frames, performance requirements can be achieved under ideal conditions.In the view of unknown disturbance of motor’s torque and vehicle’s velocity in real condition, the extended state observer(ESO) is used to observe and compensate total disturbance of system, and the PI control method is used to control the objects which is compensated by ESO. Simulation experiment shows the improvement of stabilization accuracy of improved method.