A Compliant, High Precision, Pneumatic Rotary Drive for Robotics

Abstract:
We present a new compliant rotary drive unit designed for the use in robotics. The drive unit is suitable especially for the use in human-robot collaboration. It makes use of the natural elasticity of compressed air to realize intrinsic compliance and adjustable stiffness. We use three working chambers with flexible walls and variable volume to avoid the stick-slip phenomenon and to enable high precision positioning. Furthermore, the drive is able to operate in continuous rotation. In the present paper, we explain the mechanical design as well as the realized laboratory test stand. We derive the equations to calculate the static torque distribution and compare the theoretical data to the measurement results of the laboratory test stand. The gathered practical experience regarding the different types of working chambers that we use is presented and we discuss the achieved static torque distributions. Finally we give an outlook on further design principles and possible future research.