Dynamic and tip-over stability analysis of a planetary wheeled stair-climbing wheelchair

In this paper, the design of the mechanism and the control system of a planetary wheeled stair-climbing wheelchair is introduced. The dynamic model of the planetary wheel clusters is established based on Lagrange equation, and the angle acceleration curves are studied with various given equivalent torques. Stability margin of the wheelchair is analyzed in detail during a single step climbing procedure. According to the simulation results, the control law of wheelchair's angle is derived from the projection of the wheelchair's CG on the condition that the wheelchair's stability is always maintained. The wheelchair can be easily operated by an assistant accordance with the control law.