Development of an omni-directional mobile robot with two automated guided driving modules

Wheeled mobile robots equipped with normal tires are used widely for transporting materials in industrial fields. High maneuverability especially omni-directional mobility in the floor is desired in narrow or crowded areas. An omni-directional mobile robot is developed in this paper by using two automated guided driving modules in a tandem layout. Each module has a suspension-like mechanism on the upper layer and a rotatable driving chassis with powered wheels on the lower layer. A kinematics model is built for this mobile robot, and a cross coupling control algorithm is developed for its omni-directional movement. An on-board camera is placed on the center of the robot to measure its pose deviations with respect to guide paths. In order to improve the accuracy of vision measuring, a plane target with the grid pattern is used to calibrate the intrinsic, distortion and extrinsic parameters of the on-board camera. This camera is then used to measure the pose deviations in the omni-directional motion experiment. The experiment results show the feasibility of that the combination of two guided driving modules can be used to improve the maneuverability of mobile robots.