Multi-roller, planetary traction drives offer a unique combination of compactness, high efficiency, and high torsional stiffness in high ratio drives. They have the added advantages of back-lash-free operation, low noise and vibration, no gear cogging, and smooth torque transfer in bi-directional operation. Combining traction rollers and gears yields further benefits in compactness (high torque capability) without the sacrifice of the inherent advantages of roller-gear drives. A typical drive employs a planetary arrange ent of gears and rollers consisting of a sun roller gear, two concentric clusters of stationary, roller-gear planets, and a ring gear. The low torque, high speed input is supplied to the sun gear, and the high-torque, low-speed output is taken from the ring gear.Preliminary designs of three roller-gear and two roller drives were completed in Phase I to assess their feasibility for use in a laboratory telerobotic manipulator. These include a dual-input, pitch-yaw joint drive utilizing cone rollers and zerol bevel gears, drives for a wrist-roll and hinge joint utilizing cylindrical rollers and spur gears, and planetary roller drives for the wrist-roll joint and large gearhead. The five roller-gear and roller drives examined in this program are technically feasible for robotic positioning devices.Potential Commercial Application:Roller-gear drives are ideally suited for both terrestrial and space applications, for servo positioning devices, actuators, and high-speed, compliant-motion robots being developed for manufacturing assembly tasks, and in speed changers for office and other light duty commercial machines.STATUS: Project Proceded to Phase II
