Identification procedure for McKibben pneumatic artificial muscle systems

This paper proposes a procedure for identifying a hybrid system model of a pneumatic artificial muscle that vertically suspends a mass. The obtained model involves if-then formulation and nonlinearities such as flow dynamics and friction because it is derived from mechanical and hydrodynamic equations and is developed with empirical modifications. Via analysis of the hybrid nonlinear system, we can clarify several dominant parameters characterizing the PAM dynamics in terms of steady-state and transient characteristics respectively. Based on the analysis result, then, a reasonable identification procedure can be composed. Furthermore, with a practical testbed system of the PAM system, we validate the proposed procedure producing the hybrid model under several load conditions.