Prescribed Performance-based Chattering-free Tracking Control for Pneumatic Muscle Actuators

Because of pneumatic muscle actuators' (PMAs) wide applications, the tracking control performance of a PMA should be limited to a suitable range to ensure the system safety, but the precision control of PMAs is challenging due to the slow response feature of the PMA. This paper presents a chattering-free prescribed performance tracking control for PMAs. The prescribed performance function is firstly defined to describe the PMA motion constraints and transform the constrained system into an unconstrained one. By designing the relationship between the PMA states and proxy, tracking errors of the system is utimately uniformly bounded, and the PMA motion is limited in prescribed range. The controller turns out to be a chattering-free strategy, thus it can cope with the system's slow response to a certain extent. Experiments are conducted to verify the effectiveness of the proposed method.