Flatness-based trajectory control of a pneumatically driven carriage with model uncertainties

Abstract

This paper presents a flatness-based control under uncertainties for a carriage driven by two pneumatic muscle actuators. First, the modelling of the mechatronic system is addressed. The pneumatic system part is characterised by dominant non-linearities, which have been identified and approximated by polynomial functions. Exploiting differential flatness with carriage position and mean muscle pressure as flat outputs, a trajectory control is designed and implemented. Disturbance behaviour and tracking accuracy concerning remaining model uncertainties are significantly improved by observer-based disturbance compensation. Measurements demonstrate an excellent control performance and emphasize both applicability and potential of this innovative actuator.