Wirelessly Powered Zero Net Magnetic Torque Motor for Tissue Regenerating Robotic Implant
Jack Davies, Jialun Liu, Cameron Duffield, Zihan Zhao, Dana Damian, Shuhei Miyashita
AI summary
Problem
Long-term robotic implants require safe wireless actuation, but conventional rotating magnetic fields induce dangerous net torque on the patient's body.
Approach
The motor uses an alternating magnetic field and a mirrored ratchet-pawl mechanism to produce unidirectional torque while canceling net body torque, driven by a single external coil.
Key results
- Zero-net-torque wireless motor architecture design
- Experimental output torque of ~0.5 mNm comparable to conventional ungeared motors
- Successful ex vivo stretching of porcine esophagus tissue
- Linear torque scaling with magnetic flux density and step-out frequency characterization
Why it matters
Enables safe, long-term wireless actuation for in vivo robotic implants, advancing minimally invasive treatments for gastrointestinal and tissue regeneration therapies.
Abstract
In biomedical engineering, robotic implants have shown new methods to restore and improve bodily function and regenerate tissue. A significant challenge with the design of these devices is to safely actuate them for weeks or months while they reside in a patient’s body. The application of a rotating magnetic field offers a solution to remotely transfer torque. However, this method will cause a net torque on the body within the field, which will cause rotational motion of the implant. Here we present a wirelessly-driven magnetic motor which can be driven with an external magnetic field, using an electromagnetic coil(s), to control a robotic implant. Due to the magnetic torque canceling mechanism, this wireless motor is actuatable with a single coil and produces no net torque on the entire body. When physically tested, the motor was able to produce around 0.5 mNm of torque, which is comparable to conventional ungeared motors of the same size. The motor was demonstrated in a robotic implant and successfully applied force to stretch a porcine esophagus.