Development of a compact and lightwight built-in tension sensor for pneumatic artificial muscle

Abstract

Musculoskeletal robots using MPA are known to be able to achieve dynamic motions such aswalking and running. However, these robots were often controlled by trial and error, such as adjusting the timing of pressure application. We focus on the antagonistic drive, which is a characteristic of the musculoskeletal system, and have proposed a tension-feedback cooperative control method that generates periodic motion by autonomous coordination of antagonist muscles. In this control method, it is necessary to measure the tension applied to the MPA, and in the previous study, the tension was measured by connecting a load cell in series with the MPA. In this paper, we propose a lighter and smaller tension sensor that is built into the end part of the MPA. We designed the sensor and developed a prototype, and confirmed the operation of the sensor through experiments. From experimental results, it was confirmed that the developed tension sensor has hysteresis but generally works as expected.