Characteristics verification of pneumatic artificial muscles for compressive loading

Abstract

A McKibben pneumatic actuator (MPA) is an artificial muscle. Many studies have attempted to investigate the tension exerted by the MPA. However, the MPA also exerts a pushing force when it is compressed. The MPA pushing force affects the motion of robots driven by the MPAs. Therefore, this study aimed to verify the characteristics of the MPA for a compressive load. Knowledge of the compression characteristics can be applied to the motion analysis and modeling of the MPA, and the utilization of the MPA as a structural material. First, a compression test was developed. A compression test of the MPA was conducted to verify the relationship among the input pressure, MPA length, and pushing force. In addition, the deformation mode was measured using the captured images. The pushing force does not monotonically increase with the strain because it deforms in the bending direction. The deformation mode and pushing force differ depending on the end condition. Furthermore, the hysteresis of the MPA and the effects of variations in its characteristics were discussed.