A review of control schemes for hydraulic stewart platform flight simulator motion systems

Abstract

This paper offers a brief review of hydraulic Stewart platform related control schemes, for purpose of obtaining a guideline for high performance flight simulator motion system control strategy design. The motion tracking control schemes for a pure Stewart platform for an outer-loop are discussed first, then applicable inner-loop hydraulic actuator control strategies are introduced. Inverse dynamics control, force feedforward control, adaptive and robust control schemes are discussed for the outer-loop mechanical system, while feed- back linearization control, cascade pressure difference control as well as other simple and advanced control schemes are discussed for the inner-loop hydraulic system. Based on an analysis of system requirements of the control system after the review, an novel sensor based Incremental Nonlinear Dynamic Inversion (INDI) controller is introduced to deal with the hydraulic actuator. The robustness of INDI is verified and compared with model- based controller by simulation. Finally the possible application of INDI to outer-loop Stewart platform control is discussed.