Analysis of nonholonomic constraints about a variable structure bicycle robot

A kind of bicycle robot which can work both as a bicycle and a segway is proposed in the paper. Motion parameters are derived from the principle of kinemics. Constraint equations are deduced by means of recursion based on the assumption of rolling wheels without slipping. Computer simulations are carried out on a virtual prototype. The results show that there are seven generalized coordinates in the bicycle system mentioned in the paper. Among them there are only four independent speeds. They are the rotational speed of the roll angle of the frame, the two rotational speeds of the two wheel forks, and the rotational speeds of either wheel. The rotational speed of yaw angle of frame, the rotational speed of the pitch angle of frame, and the rotational speeds of the other wheel both are the function of the four independent speeds. The simulation results based on virtual prototype are consistent with the theoretical analysis. Then the validity of the theoretical analysis of nonholonomic constraints is verified accordingly.