Motion Planning of Multi-Robots Object Transport with Deformable Sheet

Using a deformable sheet to handle objects is convenient and found in many practical applications. For object manipulation with multi-mobile robot team through deformable sheets, modeling of the robots-sheet-object system is a main challenge, since there are complex interactions among the robot team formation, deformable sheet and the object. Thus, in this paper, a virtual variable cables model (VVCM) is proposed to simplify the modeling of the robots-sheet-object system with $N$ robots. With the VVCM, we can compute the kinematics of the robot team and manipulate the object with the changing of robot team formations. We further extend the VVCM to a motion planner with the capabilities of both bypassing and crossing obstacles, since the height of the object is controllable in this case. The motion planner can be formulated as a formation optimization problem. Then, local paths can be planned with the computed formation. Simulation and experimental results with different robot team sizes show the effectiveness and versatility of the proposed VVCM. The motion planner can successfully plan an obstacle crossing path in complex scenarios where other benchmark planners fail.