Compact drive system for planetary rovers and space manipulators

Space robotics requires a new generation of actuators that have high torque densities and high efficiencies, high positioning resolutions, high torque capacities and torsional stiffnesses. Ideally they should be lightweight and low-cost. This paper presents a new hardware actuator technology concept to address the above needs. In the concept, a compact integrated motor-transmission-joint mechanism is optimized for size and torque density, while providing good joint support. This is achieved by novel arrangement of multi-function mechanical components and external-rotor motor technology and advantageous use of structural symmetry. Finite element results show the potential to deliver more than 200 Nm of continuous torque at 50 Deg/s in a package as small as a human elbow joint. With its small size and weight and its large torque output, the proposed actuator concept could benefit numerous applications, ranging from space manipulators to actuated prosthetics and medical devices.