Cooperative transportation of a single object by omnidirectional robots using potential method

This paper presents a robot navigation method using a potential method to realize cooperative transportation of a single object by multiple omnidirectional mobile robots. In cooperative object transportation by mobile robots, the complex motions of robots are required to realize independent 3DOF maneuvering of an object. Holonomic and omnidirectional mobile robots are used for the cooperative transportation since it has no constraints among its 3DOFs. To navigate omnidirectional robots to a target with no collision with its environments such as walls, doors, the potential method is introduced. A potential field gives repulsive power to robots and an object simultaneously depends on each location. To maintain geometric constraints between the robots and an object, such as relative distances and orientations, a set of repulsive forces are combined and transformed into the 3DOF space. By using the 3DOF input (a set of x- and y-forces and a moment about z-axis), a single object can be transported by multiple robots with maintaining its formation but no collision with environments. The proposed method is evaluated by experiments using two omnidirectional robots with active-caster drive systems.