Robot joint unit equipped with a joint torque sensor

Robot Joint Unit Equipped with a Joint Torque Sensor for Measuring Stator Reaction Torque

This technology is a robot joint unit featuring a joint torque sensor that positions the drive unit's stator between the base and the joint torque sensor, measuring the reaction torque applied to the speed reducer from the output link through the deformation of the sensing frame between the stator and the base.

Conventional joint torque sensors are located between the speed reducer and the output link, where they are subject to direct vibration from the reducer, leading to measurement errors, reduced overall joint stiffness, and restricted rotation angles due to wiring constraints.

This technology proposes placing the joint torque sensor between the drive unit's stator and the base to measure reaction torque, utilizing a Wheatstone bridge circuit on the sensor frame's connecting beams, and routing wiring through a hollow shaft. Applicable to collaborative robots and precision manipulators, it ensures both high measurement accuracy and joint stiffness while enabling infinite rotation.

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Key Features:

• A drive unit comprising a base, a stator supported by the base, and a rotating rotor to provide input torque
• A speed reducer that receives input torque from the drive unit and reduces it to generate increased driving torque
• An output link that receives driving torque from the speed reducer to rotate and drive an external load
• A joint torque sensor positioned on the base to detect the reaction torque acting on the speed reducer from the output link

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of a low-cost robot system based on multi-degree-of-freedom passive gravity compensation.