Abstract:
We present the conceptual design for a single degree-of-freedom shoulder assistive robot powered by a direct-drive linear electric motor. Such actuators offer high bandwidth and inherent force transparency, advantageous properties for an assistive device, but traditionally have inadequate force densities. We develop a model to describe the interaction between the robot kinematics and the actuator performance, and find the optimal actuator configuration. We also demonstrate the ability of a single design of such a device to fit a wide range of patients, and determine indicative power and mass specifications for the actuator. The resulting power and mass levels of approximately 1 kg and 130W are well within the feasible range for a wearable device.