Modelling and Flatness-Based Control of a Carriage Actuated by Pneumatic Muscles

Abstract

Pneumatic muscles are innovative tension actuators consisting of textile-fibre reinforced vulcanised rubber tubing and connection flanges at both ends. They offer several advantages as compared to pneumatic cylinders: significantly less weight, no moving parts within the muscle, and higher maximum force. The main drawback is given by their non-linear characteristics demanding for sophisticated non-linear feedback control schemes. This contribution presents a non-linear control concept for a carriage driven by two pneumatic muscles in parallel connection. First, the modelling of the muscle driven carriage is described in detail. For the resulting non-linear model the differential flatness property is proven and utilised for a decoupled position and pressure trajectory control. Experimental results from an implementation of this flatness-based control scheme at a test rig demonstrate the high tracking performance and point out the potential of this new actuator. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)