EXPERIMENTAL EVALUATION OF GENERALIZED PREDICTIVE CONTROL APPLIED TO A HYDRAULIC ACTUATOR

This paper reports the results of an experimental study, which was con ducted to evaluate the performance and implementation aspects of a gen eralized predictive control (GPC) technique to an electro-hydraulic po sitioning actuator. Poor dynamics and high nonlinearities form part of the difficulty in the control of hydraulic functions which make the a pplication of adaptive controls an attractive solution. The applicabil ity of GPC to the position control of hydraulic manipulator has been i nvestigated through computer simulations in the literature. However, t here is no experimental record of applying this technique to an actual hydraulic system. A suitable plant model is established and recursive U-D factorization technique is adopted for on-line estimation of time -varying plant parameters. Experimental results are obtained from a la boratory electrohydraulic actuator test stand. Various benchmark tests , comprising step and tracking inputs, demonstrate good performance an d the promise of the technique. In spite of significant actuator dynam ics (control voltage saturation, flow nonlinearity and dry frictional nonlinearity in the hydraulic actuator), successful control tests coul d be performed repetitively.