A Hyperbolic-based Prandtl-Ishlinskii Model for a Loaded Pneumatic Artificial Muscle Actuator

This paper proposes laboratory experiments to characterize the Pneumatic Artificial Muscle Actuators (PAMA) system's hysteresis nonlinearities under load effect. In this experiment, the PAMA system has a structure that mimics the antagonistic muscles in the human body. The hysteresis loop is characterized using various magnitudes of applied voltage while considering an external load force. The experimental results show that increasing the load force causes a shift in the hysteresis loop and a decrease in maximum displacement. Finally, to model the measured hysteresis loop under different loads, the Hyperbolic-based Prandtl-Ishlinskii model (HPI) with a force-dependent weight function is proposed. The modeling results demonstrate the proposed HPI's ability to characterize the hysteresis loop of the PAMA systems under load effect.