Torque estimation technique of robotic joint with harmonic drive transmission

A joint torque estimation technique utilizing the existing structural elasticity of robotic joints with harmonic drive transmission is proposed in this paper. Joint torque sensing is one of the key techniques for achieving high-performance robot control, especially for robots working in unstructured environments. The proposed joint torque estimation technique uses link-side position measurement along with a proposed harmonic derive model to realize stiff and sensitive torque estimation. The proposed joint torque estimation method has been experimentally studied in comparison with a commercial torque sensor, and the results have attested the effectiveness of the proposed torque estimation technique.