自抗扰控制在航空成像稳定平台上的应用

ADRC Applications on a Stable Platform for Aerial Imaging

针对航空成像稳定平台工作过程中的扰动问题,本文提出采用自抗扰控制方法,对力矩波动、传感器误差等不确定因素,进行非线性的估计与动态补偿分析。该方法根据两轴直角速率陀螺平台的系统结构,导出控制系统回路的状态方程,采用跟踪-微分器安排过渡过程,非线性地观测含总扰的扩张状态变化,对反馈误差做开关式的饱和处理。由对设计系统的仿真,基于自抗扰控制模拟了航空成像稳定平台的视轴稳定与像移补偿,并对比其与PID控制在不同幅、频扰动下的跟踪效果,探讨其对不同扰动的适应能力。最后的正弦加扰的引导结果表明,自抗扰控制的影像定位精度较高,在系统受到白噪声与低频波动的干扰时,位置误差较PID控制提高了44.57%;而随输入信号与扰动频段的升高,自抗扰控制的优势有所下降。

For aerial imaging disturbance problems in the course of the stable platform’s work, we used ADRC method for estimating uncertainties such as torque ripples and sensor errors nonlinearly while compensating them dynamically. According to the structure of two-axis Cartesian rate-gyro platform, we derived the control loop state equations, arranged transition by Track-Differentiator, and observed the extended state changes including the overall disturbance nonlinearly, handling the feedback error with switching saturation. Through designing the system, we made the simulation of LOS stabilization and image motion compensation based on ADRC, comparing its tracking effect with PID under perturbations of different amplitude and frequency, and discussed its ability to deal with different disturbances. The final sine guidance result shows that ADRC method has higher image accuracy when disturbed by white noise and low frequency fluctuations, and the position error standard deviation is 44.57% higher than that of PID. The advantage of ADRC to PID becomes smaller as the frequency of input signals and disturbances become higher.