Abstract: For the lateral self-balancing problem of bicycle robot, a new balance control method is studied for a class of bicycle robot equipped with angular momentum wheel. According to the lateral balance condition of the bicycle robot, the kinematics constraint of the robot balance control is constructed, and the balance constraint is regarded as the control target. Based on Udwadia-Kalaba (U-K) theory, a torque analytical model satisfying the lateral balance of the robot was established, and a balance constraint following controller based on the model was designed. The results show that the proposed control method can realize the lateral balance of the bicycle robot and overcome the disturbance caused by the initial deviation of the lateral roll Angle θ. Through the calculation of the balance torque model, the bicycle robot is actively balanced. Compared with the traditional feedback control method, the control method based on the model design has the characteristics of fast system response, small overshot and easy to optimize the control torque. With the help of MATLAB software, the proposed control method is simulated and verified, and the lateral self-balancing control of the bicycle robot under the initial roll angular velocity of 0°/s, 1°/s, 2°/s and 5°/s is achieved. The simulation results verify the stability and effectiveness of the control system. It provides a new idea for the balance control of unmanned bicycle robot.