Abstract: To address the disturbance-dependent operation of traditional servo systems, an improved PID control method based on a disturbance observer is proposed. The disturbance observer compensates for the impact of disturbances on the servo system's operation, thereby improving the system's tracking accuracy. Simulation and experimental results demonstrate that this control method effectively improves the system's tracking accuracy and enhances the adaptability and robustness of the servo control system.
Keywords: disturbance observer; servo control system; PID control
Chinese Classification Number: TP302 Document Identification Code: B
Research on PID control method based on the disturbance observer for servo system
ZHONG Meng-wei
(Department of Automation and Electronic Engineering, Qingdao University of Science and Technology, Qingdao 266042,China)
Abstract: To solve the problems when the traditional servo control system was disturbed, an improved PID control method based on disturbance observer was proposed. To compensate the disturbance and improve the tracking accuracy of the servo system by the disturbance observer. The simulation and experimental results show that the control method can effectively improve the tracking accuracy of the system and enhances the adaptability and robustness of the servo system.
Key words: disturbance observer; servo system; PID
1 Introduction
With the application and development of high technology, the requirements for the performance of control systems are getting higher and higher. In the design of servo system controllers [1], the interference suppression performance and robust performance of the servo control system under the interference of system parameter changes and external disturbances are very important [2]. It is difficult to achieve satisfactory control effect by using conventional PID control. In order to improve the control accuracy and robustness of the servo control system, this paper proposes an improved PID control method based on the disturbance observer [3]. This method can improve the tracking accuracy of the system well, and at the same time, the introduction of the disturbance observer can effectively suppress the frictional interference of the system and improve the robustness of the system.
2. Design Principles of the Interference Observer
The basic idea of the disturbance observer [4] is to equate the difference between the actual object and the nominal model output caused by external torque disturbance and model parameter changes to the control input, that is, to observe the equivalent disturbance. An equivalent compensation is introduced into the control to achieve complete control of the disturbance. The basic structure is shown in Figure 1:
3. Design Principles of Interference Observer
4. Simulation Study
Figure 5. Sine tracking without interference observers
Figure 6. Sine tracking with interfering observers
5. Conclusion
Simulation curves reveal that conventional PID control exhibits strong limiting cycle oscillations and fails to accurately track the desired signal during the tracking process. However, the combined control of the PID controller and disturbance observer demonstrates superior tracking performance. The disturbance observer effectively suppresses both the system and the measured signal, eliminating the limiting cycle oscillations and allowing for better signal tracking. Therefore, this control system exhibits strong adaptability and robustness.
References
[1]LEE HSH,TOMMIZUKA M. Robust motion controller design for high-accuracy positioning system[J].Transactions on Industry Electronics,1996,43(1):48-55.
[2] Zhu Jiaqiang, Zhu Jihong, Guo Suofeng, et al. Robust adaptive inverse flight control based on neural network [J]. Control Theory and Applications, 2005, 22(2): 182-188.
[3] Yang Zhi, Zhu Haifeng, Huang Yihua. A review of PID controller design and parameter tuning methods [J]. Chemical Automation and Instrumentation, 2005, 32(5):1-7.
[4] Hu Zhijiang. Application of intelligent observer in servo system control [J]. Computer Simulation, 2011, 28(11):153-156.
[5] Lu Zesheng, Zhang Qiang. Fuzzy PID dual-mode control of high-precision AC servo system [J]. Journal of Beijing University of Aeronautics and Astronautics, 2007, 33(3):315-318.
[6]HS Lee. Robust Digital Tracking Controllers for High-Speed/High-Accuracy Position System [D]. Berkeley, USA: Mech. Eng. Dep, Univ. California, Berkeley, 1994.
[7] Advanced PID Control and Its MATLAB Simulation [M]. Beijing: Electronic Industry Press, 2002.
[8] Gao Xianwen, Zhao Yaping. Application and research of fuzzy immune adaptive PID control for coke oven [J]. Control and Decision, 2005, 20(12): 1346-1349.
