Abstract: In view of the difficulty of balanced control in low speed for bicycle robot without regulator weight, a front-wheel drive bicycle robot is concerned, dynamics of the robot and stable-balanced controller for the track-stand motion under 45° front-bar turning angle are investigated. Considering wheels’ turning radius, yaw angle velocity of frame and rotational velocity of rear-wheel are derived from rotational velocity of front-wheel and rotational angle of front-bar, dynamics for the system is established with Lagrange Formulation. By the linearization of under-actuated subsystem of frame rolling angle, controller for 45° front-bar turning angle track-stand motion is constructed with partial feedback linearization. Numerical simulation for the controller shows the bicycle robot can realize 45° front-bar turning angle track-stand motion quickly with appropriate controller parameters. Prototype experiment further validates track-stand motion can be achieved with torque not exceeding driving motor’s torque tolerance. The study verifies from theory and experiment that, in low running velocity, the front-wheel drive bicycle robot can keep balance only with front-bar turning and front-wheel driving torque, and regulator weight is not prerequisite.

Key words: 45° front-bar turning angle, Bicycle robot, Front-wheel drive, Partial feedback linearization, Track-stand motion