CAPT Motor: A Strong Direct-Drive Rotary Haptic Interface

2024

Miscellaneous

hi

We have designed and built a new motor named CAPT Motor that delivers continuous and precise torque. It is a brushless ironless motor using a Halbach-magnet ring and a planar axial Lorentz-coil array. This motor is unique as we use a two-phase design allowing for higher fill factor and geometrical accuracy of the coils, as they can all be made separately. This motor outperforms existing Halbach ring and cylinder motors with a torque constant per magnet volume of 9.94 (Nm/A)/dm3, a record in the field. The angular position of the rotor is measured by a high-resolution incremental optical encoder and tracked by a multimodal data acquisition device. The system's control firmware uses this angle measurement to calculate the two-phase motor currents needed to produce the torque commanded by the virtual environment at the rotor's position. The strength and precision of the CAPT Motor's torque and the lack of any mechanical transmission enable unusually high haptic rendering quality, indicating the promise of this new motor design.

@misc{Javot24-HSD-CAPT,
  title = {{CAPT} Motor: A Strong Direct-Drive Rotary Haptic Interface},
  author = {Javot, Bernard and Nguyen, Vu H. and Ballardini, Giulia and Kuchenbecker, Katherine J.},
  howpublished = {Hands-on demonstration presented at the IEEE Haptics Symposium},
  address = {Long Beach, USA},
  month = apr,
  year = {2024},
  doi = {},
  url = {https://youtu.be/_GKC6jYNTEA},
  month_numeric = {4}
}