A High-Precision Control Scheme Based on Active Disturbance Rejection Control for a Three-Axis Inertially Stabilized Platform for Aerial Remote Sensing Applications

Xiangyang Zhou,Zhuangsheng Zhu,Chao Yang,Libo Zhao,Beilei Zhao

doi:10.1155/2018/7295852

Abstract

This paper presents a high-precision control scheme based on active disturbance rejection control (ADRC) to improve the stabilization accuracy of an inertially stabilized platform (ISP) for aerial remote sensing applications. The ADRC controller is designed to suppress the effects of the disturbance on the stabilization accuracy that consists of a tracking differentiator, a nonlinear state error feedback, and an extended state observer. By the ADRC controller, the effects of both the internal uncertain dynamics and the external multisource disturbances on the system output are compensated as a total disturbance in real time. The disturbance rejection ability of the ADRC is analyzed by simulations. To verify the method, the experiments are conducted. The results show that compared with the conventional PID controller, the ADRC has excellent capability in disturbance rejection, by which the effect of main friction disturbance on the control system can be weakened seriously and the stabilization accuracy of the ISP is improved significantly.

Highlights

It is of crucial importance for an aerial remote sensing system to obtain the high-resolution images under a nonideal multisource disturbance environment
The generalized outputs of the inertially stabilized platform (ISP) control system, z1 and z2, are obtained by the extended state observer (ESO). z1 is the angle value measured by position and orientation system (POS) in the position loop of the three-axis ISP system, z2 is the derivative of the angle, and z3 is the compensatory amount of the ESO to the disturbance in the ISP control system
This paper investigates the high-precision control method for a three-axis inertially stabilized platform (ISP)

Summary

Introduction

It is of crucial importance for an aerial remote sensing system to obtain the high-resolution images under a nonideal multisource disturbance environment. In [5], the model uncertainties and unmeasurable disturbances existing objectively are solved by introducing internal model control for a two-axis ISP system. A large number of simulation experiments show that the ADRC algorithm is simple to detect and compensate the disturbance of the control object automatically [13, 14]. This design methodology requires very little information about the plant dynamics, is very easy to tune, and has a very good disturbance rejection capability. To improve the ability of disturbance rejection of an aerial three-axis ISP, a disturbance rejection scheme based on the ADRC is proposed.

Background

Design of the ADRC Controller

Simulation Analysis

Experimental Verification

Findings

Conclusion