Force-based cooperative manipulation of highly deformable materials

This work is concerned with the automated manipulation of highly deformable materials, e. g., fabrics, textiles, leather, and adhesive foils. Although these materials are used in many industries, its handling is still mostly done manually. This is mainly due to the materials' complex geometric properties, i. e., the large scale and high parts variance in combination. To tackle the main challenges while providing maximum flexibility, this work proposes a force-based manipulation approach, where several manipulators cooperatively handle the material. For this purpose, suitable model-based control concepts are developed and investigated on a lab-scale demonstrator. The proposed demonstrator provides the basic functionality for a so-called preforming task, i. e., a scenario encountered during the manufacturing of fiber reinforced plastics where the deformable material is draped over a complex mold. To solve the preforming task including the pick-up, the transportation, and the lay-up of a strip-like material on a complex mold, the developed methods and control concepts are combined in a force-based motion planning framework. The proposed framework does not rely on preplanned position trajectories but calculates the movements of all manipulators on-line and can promptly react to external disturbances. Experimental results on the demonstrator underline the feasibility and performance of the presented approach for the lay-up of different highly deformable materials on a double-curvature mold.