Robust manipulation of deformable objects by a simple PID feedback

Robust manipulation strategies of deformable objects is presented. Manipulation of deformable objects can be found in many fields such as the garment industry and food industry. Guidance of multiple points on a deformable object is a primitive operation in the manipulation of deformable objects. In this guidance, the points often cannot be manipulated directly. A model of the manipulated deformable object is needed in order to perform these operations. It is, however, difficult to build a precise model of a deformable object. Thus, we need a robust control scheme that allows us to realize the operations successfully despite discrepancy between a manipulated deformable object and its model. We firstly derive a mathematical model of deformable objects for their manipulation. Second, indirect simultaneous positioning operations of deformable objects are formulated. Then, we propose a PID feedback control law with the rough object model to realize the manipulation. Furthermore, we propose a simple PID feedback control law without deformation model. The validity and the robustness of the proposed manipulation method is shown through simulation results.