Composite adaptive control based on historical data for electro-hydraulic system driven by dual servo motor-pump with unknown disturbance

Author(s):  
Xiaofu Zhang ◽  
Guanglin Shi

This article presents a composite adaptive control method to improve the position-tracking performance of an electro-hydraulic system driven by dual constant displacement pump and dual servo motor named as a novel electro-hydraulic system with unknown disturbance. A composite adaptive controller based on backstepping method is designed to estimate the uncertainties of electro-hydraulic control system, including the damping coefficient and elastic modulus. In order to release the persistent excitation condition of conventional adaptive control, which is often infeasible in practice, a prediction error based on the online historical data is used to update the estimated parameters. Furthermore, a disturbance observer is used to estimate the disturbance including the unmeasurable load force, friction and other unmodeled disturbance. The experiment results are provided and compared with other methods to verify the effectiveness of the proposed method, and the results have indicated that the proposed method has a better position-tracking performance with the convergent estimated parameters.

Machines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 181
Author(s):  
Yaowen Ge ◽  
Xiaowei Yang ◽  
Wenxiang Deng ◽  
Jianyong Yao

The electro-hydrostatic actuator (EHA), the actuator of electric drive and hydraulic transmission, is competitive since it is small in size, light in weight and high in power density. However, the existence of the velocity loop error of servo motors, unmodeled dynamics and highly nonlinear uncertainties restrict the improvement of the tracking accuracy of the EHA system. In order to achieve high-precision motion control of EHAs, a RISE-based composite adaptive control scheme is proposed in this paper. In the proposed composite adaptive control design, a novel parameter adaptive law is synthesized to compensate for the parametric uncertainties and a robust integral of the sign of error (RISE) feedback is utilized to suppress the adverse effects caused by the lumped disturbances, including the velocity loop error of a servo motor and other unmodeled dynamics. The synthesized parameter adaptive law possesses the advantage of fast convergence, which is beneficial to achieve transient tracking performance improvement. In addition, the proposed controller is more suitable for practical applications since it is chattering free. The closed-loop system stability analysis shows that the proposed control scheme guarantees an excellent asymptotic tracking performance. Finally, comparative simulations are conducted to verify the high-performance nature of the proposed controller.


1993 ◽  
Vol 115 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Y. P. Yang ◽  
J. S. Chu

A new dc motor control technique for the Coulomb friction compensation is proposed. The technique uses an adaptive velocity control scheme for a dc servo motor with on-line estimated parameters, including a Coulomb friction parameter, which is a combination of the Coulomb friction torque, motor time constant, moment of inertia of the motor, and sampling time of the discrete-time motor model. The estimation model used in the adaptive control process is validated off-line by a pseudo-linear regression algorithm for system parameters in a linear ARMAX model, and by adaptive Kalman filters for the Coulomb friction parameter described as pseudo-random binary sequences. The adaptive controller consists of a friction compensator and a PID controller, whose gains are adjusted adaptively in terms of estimated parameters. The proposed adaptive control law is implemented and tested on a microprocessor-based dc servo motor, and is applicable to many dc-motor-driven precision servo mechanisms. Experimental results are shown to be superior to those of conventional PID controls in terms of parameter fluctuation.


Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 20
Author(s):  
Manh Hung Nguyen ◽  
Hoang Vu Dao ◽  
Kyoung Kwan Ahn

In this paper, an active disturbance rejection control is designed to improve the position tracking performance of an electro-hydraulic actuation system in the presence of parametric uncertainties, non-parametric uncertainties, and external disturbances as well. The disturbance observers (Dos) are proposed to estimate not only the matched lumped uncertainties but also mismatched disturbance. Without the velocity measurement, the unmeasurable angular velocity is robustly calculated based on the high-order Levant’s exact differentiator. These disturbances and angular velocity are integrated into the control design system based on the backstepping framework which guarantees high-accuracy tracking performance. The system stability analysis is analyzed by using the Lyapunov theory. Simulations based on an electro-hydraulic rotary actuator are conducted to verify the effectiveness of the proposed control method.


2021 ◽  
Vol 2107 (1) ◽  
pp. 012064
Author(s):  
S.M. Othman ◽  
Noorhazirah Sunar ◽  
Hassrizal H.B ◽  
A.H. Ismail ◽  
M.N. Ayob ◽  
...  

Abstract Electro-Hydraulic Actuator (EHA) system is a third order non-linear system which is highly suffer from system uncertainties such as Coulomb friction, viscous friction and pump leakage coefficient which makes this system more complicated for the designing of the controller. The Proportional-Integral-Derivative (PID) controller has proposed in this paper to control EHA system and main problem in its application is to tune the parameter to its optimum value. Two different methods are used to tune the PID controller which are trial and error and Ziegler-Nichols method. MATLAB Simulink is used to simulate the system. In order to determine the performance of EHA system for the position tracking. 3 different of external disturbance such as 0N, 5000N and 10000N has been injected into the system. Simulation results show that the Ziegler-Nichols fine tuning method provides the better tracking performance when compared to the trial and error method for every specific disturbance setting. The Ziegler Nichols method provides better disturbance rejection as the performances indexes such as percentage overshoot, settling time and steady state error are not affected by the varying of disturbance.


2010 ◽  
Vol 29-32 ◽  
pp. 155-162
Author(s):  
Li Jun Zheng ◽  
Xin Mei Cheng ◽  
Shan Shan Chen

In order to solve the electro-hydraulic system position tracking control problem, which caused by the nonlinear system friction torque disturbance, a model-free algorithm for the friction torque adaptive identification and compensation was put forward. The algorithm is based on the application mathematics knowledge and matching & following principle. It can accommodate to all situations with the friction torque (force) variety. The simulation result indicates that the algorithm can restrains the interference of the friction torque (force) effectively, and the system’s low speed character and tracking performance were been improved.


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