Development of Sliding Mode Controller Based on Internal Model Controller for Higher Precision Electro-Optical Tracking System

Abstract

The electro-optical tracking system (ETS) on moving platforms is affected by the vibration of the moving carrier, the wind resistance torque in motion, the uncertainty of mechanisms and the nonlinear friction between frames and other disturbances, which may lead to the instability of the electro-optical tracking platform. Sliding mode control (SMC) has strong robustness to system disturbances and unknown dynamic external signals, which can enhance the disturbance suppression ability of ETSs. However, the strong robustness of SMC requires greater switching gain, which causes serious chattering. At the same time, the tracking accuracy of SMC has room for further improvement. Therefore, in order to solve the chattering problem of SMC and improve the tracking accuracy of SMC, an SMC controller based on internal model control (IMC) is proposed. Compared with traditional SMC, the proposed method can be used to suppress the strongest disturbance with the smallest switching gain, effectively solving the chattering problem of the SMC, while improving the tracking accuracy of the system. In addition, to reduce the adverse influence of sensor noise on the control effect, lifting wavelet threshold de-noising is introduced into the control structure to further improve the tracking accuracy of the system. The simulation and experimental results verify the superiority of the proposed control method.

Multi-Channel Phase-Compensated Active Disturbance Rejection Control with an Improved Backstepping Strategy for Electro-Optical Tracking Systems

“…The PSD provides the position errors between the target of the laser light and the pointing target to control the ISP. In Figure 2, the dynamic model of an ISP can be described as [15]:…”

“…Sliding mode control (SMC) is another technique that can effectively suppress perturbations in most photoelectric systems due to its strong robustness. However, it is noted that the chattering phenomenon is inevitable in traditional SMC methods [15]. Despite these control methods being capable of achieving some level of disturbance prevention, their application in ETSs and in industry is limited due to the aforementioned reasons.…”

Design of Backstepping Control Based on a Softsign Linear–Nonlinear Tracking Differentiator for an Electro-Optical Tracking System

“…An electro-optical tracking system (ETS) is a piece of complex and high-precision servo tracking equipment integrating optical, mechanical, and electronic technology. It has the characteristics of a fast response speed, a low tracking error, and strong disturbance resistance [1]. These devices are mainly used for real-time tracking and measurements of moving targets, and are widely employed in the fields of target observation, laser communication, quantum communication, aviation, aerospace, automated production, and other fields [2,3].…”

Practical Adaptive Fast Terminal Sliding Mode Control for Servo Motors

“…Over the past decade, numerous control strategies have been designed to suppress the negative effects of nonlinearities and uncertainties in servo motors, such as PID control [7], active disturbance rejection control [8], adaptive control [9], observer-based controllers [10], sliding mode control (SMC) [11], and so on. Among them, SMC is a robust control strategy and has been extensively utilized in a broad range of applications, such as industrial actuators, robotics, power electronics, biomedical, and aerospace [12][13][14][15][16][17][18][19]. However, the SMC method has a few drawbacks, such as asymptomatic output convergence, which is not desirable for accurate control of the servo motor.…”