Application of an Adaptive Model Following Control Technique to a Hydraulic Servo System Subjected to Unknown Disturbances

1991 ◽  
Vol 113 (3) ◽  
pp. 479-486 ◽  
Author(s):  
J. S. Yun ◽  
H. S. Cho
Keyword(s):  
External Load ◽  
Position Control ◽  
Experimental Studies ◽  
Control Technique ◽  
Time Varying ◽  
Adaptive Model ◽  
Model Following Control ◽  
Model Following ◽  
Unknown Disturbances ◽  
Hydraulic Servo

This paper deals with a position control of hydraulic servo systems subjected to unknown and time-varying external load disturbances. Since hydraulically operated processes are often subjected to unknown disturbances, an adaptive model following control (AMFC) scheme was derived based upon the Liapunov’s Direct Methods which was employed by Monopoli (1981). As an adaptation criterion this method utilizes an ultimate boundary of the uncertain parameters associated with the plant dynamics and the unknown disturbances. The performance of the derived adaptive controller is evaluated through simulation and experimental studies. The results show that the proposed AMFC is fairly insensitive to unknown and time-varying external load disturbances, yielding much better response characteristics, compared with those of a conventional constant PI feedback controller.

scholarly journals Combining Input Shaping and Adaptive Model-Following Control for Vibration Suppression

2021 ◽  
Vol 25 (1) ◽  
pp. 56-63
Author(s):  
Jinhua She ◽  
Lulu Wu ◽  
Zhen-Tao Liu ◽  
◽  
◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Golden Section ◽  
Input Shaping ◽  
Adaptive Model ◽  
Servo Systems ◽  
Elastic Load ◽  
Model Following Control ◽  
Model Following ◽  
Input Shaper ◽  
Precision Motion

Vibration suppression in servo systems is significant in high-precision motion control. This paper describes a vibration-suppression method based on input shaping and adaptive model-following control. First, a zero vibration input shaper is used to suppress the vibration caused by an elastic load to obtain an ideal position output. Then, a configuration that combines input shaping with model-following control is developed to suppress the vibration caused by changes of system parameters. Finally, analyzing the percentage residual vibration reveals that it is effective to employ the sum of squared position error as a criterion. Additionally, a golden-section search is used to adjust the parameters of a compensator in an online fashion to adapt to the changes in the vibration frequency. A comparison with other input shaper methods shows the effectiveness and superiority of the developed method.

Dual extended state observer-based backstepping control of electro-hydraulic servo systems with time-varying output constraints

2019 ◽  
Vol 42 (5) ◽  
pp. 1070-1080
Author(s):  
Guichao Yang
Keyword(s):  
Hydraulic System ◽  
State Observer ◽  
Extended State Observer ◽  
Time Varying ◽  
Extended State ◽  
Servo Systems ◽  
Output Constraints ◽  
Unknown Disturbances ◽  
Hydraulic Servo ◽  
Mismatched Disturbances

In this paper, a novel nonlinear robust controller ensuring time-varying output constraints for the double-rod hydraulic servo systems in the presence of largely unknown matched and mismatched disturbances is proposed. By employing two extended state observers for each channel of the load dynamics and pressure dynamics of the considered hydraulic system, the large matched and mismatched disturbances are successfully compensated. In addition, a time-varying barrier Lyapunov function (BLF) of asymmetric type has been employed to make sure that the position output is never violated. The resulting controller is synthesized using the backstepping procedure. The stability of the whole closed-loop hydraulic system associated with the dual extended state observer (ESO)-based controller is strictly guaranteed. In theory, the proposed control strategy can not only ensure the output satisfy the preset constrained space, but also enhance the output tracking performance when the system faces various largely unknown disturbances. The effectiveness of the proposed controller has also been demonstrated via comparative simulation results.

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