Design and Development of Highly Torque Dense Robot Joint Using Flexible Shaft Based Remote Actuation

Abstract

Remote actuation is an important design technique to reduce the moving mass of robots for safety. This paper proposes a remote actuator based on the flexible shaft for robot joints. High torque density is achieved at the robot joint, rated at 95 Nm with a low moving mass of 2.6 kg (1.8 kg at Joint + 0.8 kg at Link). The design methodology is proposed to develop a remote actuator using a flexible shaft with low-moving mass and torsional compliance at the remote joint with three progressive prototypes. The design of the conduit and link utilized for routing flexible shaft across a joint through the links is analyzed and discussed. A comparison is made with on-joint actuation and potential off-joint actuation using catalog data in terms of torque density, highlighting the potential of remote actuation using a flexible shaft for high payloads at high torque density.