A multibody approach for modelling universal wheels of mobile robots

Typical mobile robot structures (e.g., wheelchair or car-like robots) do not have the required mobility for common applications such as displacement in a corridor, hospital, office, etc. New structures based on the ‘universal wheel’ (i.e., a wheel equipped with free rotating rollers) have been developed to increase mobility. However, these structures have important drawbacks such as vertical vibration and limited load capacity. In order to predict both their kinematic and dynamic behaviours, the resort to a multibody approach has been envisaged in this paper and a so-called ‘cam/follower’ contact model has been developed to take the universal wheel/ground interface into account. An experimental comparison of the model as well as the simulation of three designs of universal wheels are proposed before concluding the paper.