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

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.

An Improved Fuzzy Neural Network Compound Control Scheme for Inertially Stabilized Platform for Aerial Remote Sensing Applications

“…Compound Controller. Figure 3 shows the block diagram of a traditional three-loop control system for the ISP [13,14]. G-pos, G-spe, and G-cur separately represent the controllers in the tracking loop, stabilization loop, and current loop.…”

“…In [12], to realize a balance between high performance and complexity, a dual-stage inertial stabilization system based on frequency-domain analysis is established. In [13,14], a high-precision control scheme based on active disturbance rejection control (ADRC) and a model reference adaptive control (MRAC)/ PID command scheme are, respectively, proposed for the disturbance rejection of the ISP.…”

“…To verify the scheme, the simulations and experiments are carried out, respectively. Compared to our previous publications [13,14], the novel and significant contribution of this paper is to propose an improved FNN/PID compound control scheme, in which the idea of variable universe and the BP algorithm are combined to improve the ability of disturbance rejection.…”

“…Generally, an aerial remote sensing system consists of four main components, a three-axis ISP, a remote sensing sensor, a position and orientation system (POS), and an aviation platform. When the aviation platform rotates or jitters, the control system of the ISP gets the high-accuracy attitude reference information measured by the POS and then routinely controls the LOS of the imaging sensor to achieve accurate pointing relative to ground level and flight track [13,14].…”

“…International Journal of Aerospace Engineering E x , E y , and E z , respectively, stand for the photoelectric encoder which measures the relative angular rate between gimbals. M r , M p , and M a , respectively, stand for the gimbal servo motor of the three gimbals [13,14].…”