NONLINEAR ADAPTIVE CON-TROLLER DESIGN

FOR THE STEWART PLATFORM BY
HYDRAULIC DRIVEN

XU Dongguang  DONG Yanliang  WU Shenglin  WU Bo  ZHAO Keding

(School of Mechatronic Engineering, Harbin Institute of Technology, Harbin 150001 )

Abstract: Because of high nonlinear feature of the platform driven by electro-hydraulic actuators and the serious load coupling among actuators, the fidelity and smoothness of simulator are impacted. The driven branch of the platform was as control object in the platform controller design in the past and neglecting the influence caused by load-coupling among actuators, which resulted in declining of the platform control precision, even unsteadiness. For the above reasons, taking the platform as a control object in the controller design, a nonlinear adaptive control algorithm based on acceleration robust observer for the Stewart platform is presented, and asymptotic stableness of algorithm is demonstrated by using Lyapunov method. Experiment results show that the controller proposed here has better trajectory tracking performance and higher capability of dealing with load coupling among actuators.

Key words: Nonlinear adaptive control Stewart platform Sliding mode observer Electro-hydraulic servo control system

CLC No: TP137

Received 20060406, received in revised form 20061101