Design of Drilling and Riveting Multi-functional End Effector for CFRP and Aluminum Components in Robotic Aircraft Assembly

Abstract

To fulfill the demands for higher quality, efficiency and flexibility in aviation industry, a multi-functional end effector is designed to automate the drilling and riveting processes in assembling carbon fiber reinforced polymer (CFRP) and aluminum components for a robotic aircraft assembly system. To meet the specific functional requirements for blind rivet installation on CFRP and aluminum materials, additional modules are incorporated on the end effector aside of the basic processing modules for drilling. And all of these processing modules allow for a one-step-drilling-countersinking process, hole inspection, automatic rivet feed, rivet geometry check, sealant application, rivet insertion and installation. Besides, to guarantee the better quality of the hole drilled and joints riveted, several online detection and adjustment measures are applied to this end effector, including the reference detection and perpendicular calibration, which could effectively ensure the positioning precision and perpendicular accuracy as demanded. Finally, the test result shows that this end effector is capable of producing each hole to a positioning precision within ±0.5 mm, a perpendicular accuracy within 0.3°, a diameter tolerance of H8, and a countersink depth tolerance of ±0.01 mm. Moreover, it could drill and rivet up to three joints per minute, with acceptable shearing and tensile strength.