Localization of Fabrics with Computer Vision for Composite Manufacturing

Abstract

Using fiber reinforced polymers (FRP) in industrial applications typically provides structures with lower weight compared to metals. Investment costs for automated processes are high and so far getting established in aviation applications. To introduce automation solutions together with low investment costs, the European funded project DrapeBot uses industrial robots to assist the worker in the manufacturing of FRPs. The robots are equipped with grippers that can pick up fabrics. Dependent on the size, they are either transported and placed fully by the robot, cooperatively by two robots or cooperatively with one robot and the worker. With this flexibility the automated system can be used for other manufacturing processes which raises machine utilization and thus lowers amortization time. In DrapeBot this approach will be used for aviation, automotive and maritime use cases that all use pick and place processes. To pick up the fabrics the location of the individual cut piece is needed. Computer vision is used to find the cut piece on the respective material carrier. A computer vision system using a monochrome industrial camera to find dry carbon fiber fabrics for aviation use cases was developed in earlier projects at DLR. In DrapeBot the automotive and maritime use cases introduce dry glass fibers as well as carbon fiber prepregs. To find these materials and calculate their positions, changes in the existing system had to be done. Due to the changing environments and materials the monochrome camera with optimized flash for carbon fibers was changed to a color camera using ambient lighting for image acquisition. Each color space of the color image is evaluated individually and contrast optimizations are done to use the existing algorithms for coordinate calculation. With this adapted computer vision system the localization of carbon fiber prepreg materials for the automotive use case was established and experiments with dry glass fibers showed promising results.