Experience With Sliding Mode Control of a Pneumatic Cartesian Robot

Abstract

This paper outlines experience with a 3 axis pneumatic Cartesian robot that was constructed from commercially available valves and cylinders. Experiments demonstrate that a linear PVA controller is suitable for step tracking applications. However, acceptable performance was achieved only after extensive trial and error tuning of the controller gains. Preliminary gain estimates were obtained for PVA with a Linear Quadratic (LQ) design and a linear model of the robot. Sliding Mode Control (SLM) was found to be superior to PVA in that it provided acceptable performance with minimal tuning effort. The relay nature of SLM was also found to provide a measure of friction compensation. Preliminary results for SLM as applied to circle tracking are presented.