Accuracy improvement of built-in torque sensing for Harmonic Drives

A Torque Measuring Method for Robot Joints with Harmonic Drives

“…From (16), we find that this system's output is higher than many other systems: it triples the output of single full bridge, and twice the output of three-half-bridge weighted stacking method [5].…”

“…The latter model contains sine (or cosine) waves which frequency are twice and quadruple that of the wave generator rotation [5]. Moreover, Godler et al [5] also have investigated more-than-two-order models, despite that the second-order model is proved to be accurate enough [4,5].…”

“…The ripples are mainly expressed by two models: the first-order model and the second-order model. The former only contains a sine (or cosine) wave which frequency is twice that of the wave generator rotation [4,5]. The latter model contains sine (or cosine) waves which frequency are twice and quadruple that of the wave generator rotation [5].…”

“…Accordingly, it is called bridge compensation method here. The second method cancels out ripples by weighted stacking n channels of signals from independent half bridges [5,9,10,11,12,13]. Accordingly, it is called weighted stacking method here.…”

Torque Measurement Device Using an Integrated Microdisplacement Sensor

“…(1)(2)(3) Magnetictype torque sensors have the advantage of robustness and remarkable resolution, yet they have a weakness associated with electromagnetic noise. (4) There have been other types of torque sensors that exploit strain gauges (5)(6)(7)(8)(9)(10) and optics. (4,11) Hashimoto et al have reported torque sensors using strain gauges to detect the dynamic torque applied to a harmonic drive.…”