Systematic design and optimization of robotic grippers for handling limp composite pre-shaped geometries

The growing need for sustainable mobility is driving the search for solutions to reduce energy waste and harmful environmental emissions. In this context, the design of vehicle lighting presents a promising approach. The use of composite materials, along with the automation of their manufacturing and assembly processes, is increasingly in demand to strike a balance between cost, lightweight, and the required performance of vehicle chassis. Carbon Fiber Sheet Molding Compounds allow complex car body parts to be produced through a one-step compression molding process. Manual labor represents a crucial operation in preparing the compound charge and subsequent manipulation towards compression molding. However, it directly affects productivity. The continuity between the preparation and manipulation phases can be relaxed by implementing robotic solutions to handle the pre-shaped uncured composite charge, automating loading onto the press mold. Efficient robotic handling requires grippers designed to match the shape of the compound charge. Specifically, the gripper must control the deformation of the temporary form of the composite charges, ensuring that the shape deviations stay within acceptable limits for proper fit in the compression mold. This work presents a systematic approach to designing and optimizing robotic grippers to pick up and place deformable compound layers. The key design parameter that guides this method is the maximum distortion threshold, which regulates the process in the two stages. The first stage focuses on finding the optimal balance between the lowest grasping points and acceptable distortion to define the grasping layout. In contrast, the second stage addresses the gripper structure, aiming to create the lightest, yet stiffest frame. The approach is fully integrated into a computer-assisted design platform. To validate this method, a vehicle body panel is the case study selected to design and optimize the structure of the robotic gripper.