A continuous dynamic model for an omnidirectional mobile robot

The omnidirectional mobile robots with MY wheels-II are discontinuous dynamic systems. This paper derives a continuous model from a given discontinuous dynamic model. Firstly, the problem of a previously proposed dynamic model, average dynamic model, is analyzed. It shows that the effectiveness of the average dynamic model is limited to robots under a certain class of configurations. To overcome this problem, we first derive the switching conditions of MY wheel-II. Then a continuous dynamic modeling method, using adaptive continuous curves instead of the real discontinuous contact radius in the discontinuous dynamic model, is proposed based on the switching conditions. The resulting dynamic model is a smooth NLPV model, which may then be used as one solution for the model-based control design. The effectiveness of the proposed NLPV model is verified and compared through open-loop simulations against the average model.