The applicability of an assistive walking device integrating overload protection mechanism using a torque limiter

Considering the practical usage of the assistive walking device, the user usually encounters unexpected walking motion which induces equipped motor easily breakage. In this study, we designed a torque limiter as overload protection mechanism for an assistive walking device. The material sheet plays a key role in this torque limiter. This work used the NBR (nitril-butadiene rubber) as an ideal material since the material assessment results reveal it possesses the great transmitted torque and durability. To assess the practical applicability, this work integrates this torque limiter into our developed assistive walking device to conduct the walking trials. We observe that this torque limiter can continually sustain overload torque for over five minutes and does not break the gear. To conclude, a novel torque limiter design can achieve the same assisting motions as the original gear, and it can protect the servo motor against unexpected overload torque. Finally, by integrating a torque limiter, our assistive walking device can maintain long-term service lives; further, the users can freely utilize it to prompt exercise and conduct rehabilitation.