Novel omnidirectional mobile robot with slidable base

Abstract

Omnidirectional wheeled mobile robots, which can drive in any direction without turnabout, could help increase the efficiency of transportation in factories and warehouses. However, most such robots have low load capacity or unwanted vibrations due to the structure of their wheels. To overcome these problems, this paper proposes an omnidirectional mobile robot with a slidable base. The proposed robot achieves omnidirectional mobility using conventional wheels. Its design is based on our previously developed slidable wheeled omnidirectional mobile robot but with a simpler structure and fewer motors. The synthesis of the proposed robot, including the basic structure and basic movement patterns, is first presented. A kinematic model is established, and the singular configuration of the robot is analyzed. An original movement strategy for avoiding singularities is developed considering the periodic input and stabilization of the slidable base. Simulations are conducted to verify the effectiveness of the proposed strategy. Experiments are conducted on a prototype to verify the feasibility of the proposed robot and the algorithms used to realize unlimited omnidirectional movement. The results show that the robot can achieve omnidirectional movement without reaching the singularity. As for the stabilization algorithm, although the position of the slider does not return to the exact specified value due to errors in measurement and the robot itself, it is guaranteed that the slider will not exceed the limit.