Seizing failure-tolerant differential redundant drive mechanism and control technique for two-wheeled, self-balancing vehicle

In order to maintain balance, the motors of an inverted pendulum-style, two-wheeled self-balancing vehicle need to continuously control its wheels. The vehicle is at risk of falling over if any of its motors does not function properly. Some research in this regard has been devoted to gaining redundancy by using more motors geared to a common shaft, but such technique is not effective for a seizing failure. In this paper, we propose a differential redundant mechanism to prevent a seizing failure in such vehicles. This mechanism unifies plural motors using a differential mechanism, and allows redundant motors to operate at different speeds. Therefore, the vehicle can maintain balance even if a motor fails. Furthermore, our mechanism can form a redundant system of two outputs using only three motors. We also propose a controller for this redundant mechanism that does not require changing the control mode when seizing failures occur.