Dynamic Feedback Linearization for Electrohydraulically Actuated Control Systems

Abstract

Using the dynamic inversion principal, a globally linearizing feedback control law is developed for an electrohydraulic servo system. The proposed control law is implemented on a rotational joint driven by a linear actuator. The results from experiments indicate that better uniformity of response is achieved across a wider range of operating conditions than would otherwise be possible. Improved symmetry is obtained for the extension and retraction phases of motion for an asymmetric actuator under various loading conditions and actuator positions. As a result of the improvements in linearity, significantly better performance is achieved when using linear controllers. To incorporate the effects of parametric uncertainties on the feedback linearization, a state space linear fractional representation of the parametrically uncertain linearized system is also developed. This uncertainty model is specifically suited for the design of robust control systems using the /x-synthesis and H" based approach. Electrohydraulic SystemControl. Presently, no comprehensive control strategy dealing with all the nonlinearities in electrohydraulic systems exists. Model reference adaptive 468 / Vol. 117, DECEMBER 1995 Transactions of the ASME Copyright © 1995 by ASME Downloaded From: http://dynamicsystems.asmedigitalcollection.asme.org/ on 09/16/2013 Terms of Use: http://asme.org/terms

Adaptive sliding mode control of electro-hydraulic system with nonlinear unknown parameters

“…Firstly, the feedback linearization technique was used in some research works (Re & Isidori, 1995;Shol & Bobrow, 1999;Vossoughi & Donath, 1995), but this control method did not account for system uncertainties. So several kinds of sliding mode variable structure control (SMVSC) methods are adopted in electro-hydraulic control systems by some researchers (Bonchis, Corke, Rye, & Ha, 2001;Hisseine, 2005;Hong, Kil, Tae, & Yeong, 2003;Li & Khajepour, 2005;Liu & Handroos, 1999;Wu & Shih, 2003).…”

Disturbance Observer based Feedback Linearization Control for Electro-Hydraulic Servo Systems

“…이 방법들이 제어 성 능을 향상 시켰으나, 그 구조가 복잡하고 측정된 신호의 여러 번 미분된 값을 제어기에 사용하기 때문에 측정 잡음을 증폭 시킨다 는 단점이 있다. EHS의 비선형 특성을 보상하고 제어 알고리즘 구조를 간편화하기 위하여 피드백 선형화를 이용한 제어 방법도 연구 되었다 [8]- [11]. [1].…”

Control and performance evaluation of a clutch servo system with hydraulic actuation

“…The standard control approach for such systems relies on local linearization of the dynamics around an operating point, followed by linear control design (Merritt, 1967). Other significant approaches are: nonlinear modelling (Zavarehi, Lawrence, & Sassani, 1999), feedback linearization (Vossoughi & Donath, 1995), Lyapunov like control (Sohl & Bobrow, 1999), variable structure control (Bonchis, Corke, Rye, & Ha, 2001) and H N control (Tunay, Rodin, & Beck, 2001). In the considered case, however, these standard approaches need to be revised, because a tracking problem in presence of strong nonlinearities is considered and its effects on achievable performances need to be enlightened.…”