Model-based compensation of hysteresis in the force characteristic of pneumatic muscles

This paper presents a compensation strategy for the hysteresis in the nonlinear force characteristic of pneumatic muscles. For a dynamical modelling of the hysteresis, the generalised Bouc-Wen model is employed. This model allows for the representation of highly asymmetric hysteresis. The parameters of the Bouc-Wen model are identified by measurements. An existing control structure for a high-speed linear axis actuated by pneumatic muscles is extended by the Bouc-Wen model with the identified parameters for compensation of the hysteresis. Experimental results from an implementation on a test rig show the efficiency of the proposed compensation strategy.