Application Of Gyro/Accelerometer Stable Loop For Servo System Of "Communications In Moving"

For the purpose of isolating carrier attitude’change and stabilizing tracking on airborne antenna communication system, a small airborne directional antenna servo unit was designed. As plane flying, the inertial navigation system calibrates the attitude of satellite every 20ms. To compensate for disturbance caused by carrier attitude changing during PC instructions, a stability loop tracking control method based on tri-axial gyro and accelerometer is proposed. Based on traditional servo system of current, velocity and position feedback loop, design the speed feed-forward compensation and stabilization loop. The stability loop integrates the measurement data of gyro and accelerometer and uses the principle of stabilizing tracking correction to isolate the influence of carrier attitude change for antenna tracking accuracy.This paper introduces the composition and working principle of the servo unit firstly, then calculates the parameter of motor and other structural components and builds the complete physical prototype of servo unit. The control system adopts PID algorithm to realize the of current loop controller, velocity loop and position loop, then set up simulation model of servo extension system in Matlab. According to index requirements of dynamic performance, test parameters of step response, dynamic tracking response, ramp response, velocity /acceleration and isolation degree in the simulation. The results verify that the servo unit has reached the design requirements.In order to meet the functional requirements of servo unit, the paper uses a Brushless DC motor as drive motor and designs BLDC drive printed circuit board and control circuit board based on 32 bit Soc series CPU. Then, study the control algorithm of standby, angle presetting, searching, tracking working modes and gyro stabilization loop algorithm of servo unit. A Kalman filter is proposed to estimate and compensate the gyro’s random noise signal, which can effectively improve the disturbance isolation ratio. The debugging results show that, the response time of stabilized tracking platform is less than 200ms,the dynamic tracking error is less than 0.1° and the isolation ratio is more than 97%, the system has higher tracking precision and meets the stable tracking performance of antenna positioning, tracking order and anti-interference in industrial application.