Tilting-Type Balancing Mobile Robot Platform for Enhancing Lateral Stability

In this paper, a tilting-type balancing mobile robot platform is investigated for enhancing lateral stability. In addition to pitch, yaw, and straight motion by the conventional two-wheeled inverted pendulum mechanism, it can generate roll and vertical motion by an additional tilting mechanism. The static force analysis shows that body separation tilting is more advantageous in power consumption than single body tilting, specifically when the payload to body weight is relatively small. Some design considerations are given for the determination of body structure and actuator powers. For the dynamic modeling, the titling balancing platform is assumed as a three-dimensional inverted pendulum with moving base and the nonlinear equation of motion is derived in terms of Kane's method. Then, a velocity/posture control loop is constructed, where the tilt angle reference is naturally generated according to the centrifugal force variation in following a circular path. Experimental results are given to validate the proposed mobile platform with the tilting control strategy.