Modeling and analyzing of stable equilibrium motion of a bicycle robot with front-wheel drive by using moment balance

Bicycle robot have two points contacting with its support plane, and the connecting line between these two point can be dealt with equilibrium axis when the bicycle perform regular motions. In this paper, we discuses stable equilibrium motion of a front-wheel drive bicycle robot by use of moment balance of inertial forces and gravities. Firstly, under the presupposition of rolling without sliding, recursion forms of velocities and accelerations of the robot are derived with generalized speeds. The derivations reveal there are three nonholonomic velocity constraints in the system. Secondly, stable equilibrium motion mathematical model is established by fully considering moment balance of gravities and inertial forces of the robot. The model indicates the robot system holds one under-actuated degree of freedom. Thirdly, virtual prototype is constructed in ADAMS and balancing motion is performed to validate the proposed model. And finally, numerical simulations are carried out in MATLAB to analyze stable equilibrium motion of the robot under different situations. The result shows that the bicycle robot can realize stable equilibrium motion with proper steering angle and driving angular velocity of front-wheel.