BiTSpoke: A Leg-Wheel Robot With Single-Motor Driven Actively-Transformable Spoke Wheels

Abstract

To address the issue that current transformable spoke-wheeled leg-wheel robots cannot simultaneously achieve simple structure, stable locomotion and open step climbing ability, a novel robot design method is proposed. The robot called BiTSpoke is driven by two transformable spoke wheels, with a passive wheel mounted at the tail end serving as support and reducing friction. Each transformable spoke wheel is driven by a single motor and primarily consists of two parts: a two-way hub and a one-way hub. The forward rotation of the drive motor controls the robot to move forward, while the reverse rotation of the drive motor causes relative rotation between the two-way hub and one-way hub, thereby switching between wheeled mode and legged mode. The dynamic model and maximum step climbing height of the robot were analyzed. The physical experiment results show that the wheeled motion speed can reach 50.14 mm/s in the forward direction and 43.21 mm/s in the backward direction, the legged motion speed can reach 47.43 mm/s in the forward direction and 42.55 mm/s in the backward direction on a painted desktop, mode transformation can be achieved on different terrains in 2.73 s, maximum closed step climbing height is 52 mm, which is 1.44 times the radius of the wheel, maximum open step climbing height is 61 mm, which is 1.69 times the radius of the wheel, and BiTSpoke can adapt to different terrain features. This robot is expected to be used in search and rescue (SAR) missions, leveraging its advantages of low cost and strong terrain adaptability.