Online Grasp Plan Refinement for Reducing Defects During Robotic Layup of Composite Prepreg Sheets.

High-performance composites are increasingly being used in the industry. Sheet layup is a process of manufacturing composite components using deformable sheets. We have developed a robotic cell to automate the layup process and overcome the limitations of the manual layup. Generating offline trajectories for robots and executing them without online refinement can introduce defects in the process due to uncertainties in the model of the sheet and environmental factors. Our system computes layup and grasping trajectories for the robots and refines them during the layup process based on the sensor data. We use an approach that augments physical experiments with simulations to train a Gaussian process regression model offline. The use of GPR enables us to quickly refine grasp plans and perform a defect-free layup without slowing down the layup process. We present experimental results on two components.