Fuzzy state feedback gain scheduling control of servo-pneumatic actuators

The design of a new motion controller for pneumatic actuators using local linear models is described with an application to a two-way servo-pneumatic drive under a time variable vertical load. The dominant nonlinearities in the plant are the couplings between motion and pressure, pressure and flow rate, and the friction force. The control problem in this paper is to keep the accuracy of the position control independent of the payload and piston position. For each local linear model a state feedback controller is derived. The final controller of the system is designed as a fuzzy gain scheduler of the local state feedback controllers. It is shown by experimental results that this controller is capable to handle the dominant nonlinearities of the plant and different payloads, which are kept constant during each experiment. (C) 2003 Elsevier Ltd. All rights reserved.