Under an agreement signed between CSIR-CMERI and Hiroshima University on January 18, 2018 by Director, CSIR-CMERI and President, Hiroshima University, a PhD student, Mr. Chetan Thakur, visited CSIR-CMERI as an intern under the Sakura Student Exchange Programme. The internship as carried out by Mr. Chetan Thakur from 11 Nov. to 12 Dec., 2018 under the supervision of Dr. Soumen Sen, Principal Scientist at Robotics and Automation Div. of CSIR-CMERI, Durgapur.

The work mainly involved characterization of Pneumatic Muscle as an actuation system for assist exoskeleton for domestic workers and farmers. Development of human assistive devices requires actuators to be compliant with dexterous motion of human body and to augment desired motion. Pneumatic artificial muscle (PAM) are lightweight and have low force to weight ratio, which makes it suitable for wearable assistive devices or exosuits. PAM has inherent characteristics like biological muscles to vary impedance by changing supplied air pressure. Impedance of PAM depends on the material used and dimensions of the PAM at rest. In this study, we measure impedance characteristics of McKibben type PAM by considering spring mass damper system. In this experiment we measure stiffness and damping coefficient of the PAM. These coefficients are modeled as function of air pressure, displacement and elongation velocity. This model is useful for designing appropriate control strategy when these PAMs are used in wearable assistive devices to synchronize with assisted motion.