This video demonstrates a 3-axis "MultiMotor" with singular stator and three concentric rotors, driven by a total of seven wires. It accompanies the following paper:
V. Groenhuis, G. Rolff, K. Bosman, L. Abelmann, S. Stramigioli, "Multi-Axis Electric Stepper Motor". IEEE Robotics and Automation Letters, July 2021.
Link: https://ieeexplore.ieee.org/document/9484841 and https://research.utwente.nl/en/publications/multi-axis-electric-stepper-motor
Author copy PDF (green open access): https://research.utwente.nl/files/256839289/MultiMotor_RA_L_AuthorCopy.pdf
