The purpose of this paper is to present a novel force sensing jig for robot-assisted drilling used to drill holes for the fastening of floating nut plates in aircraft assembly.
The paper describes the drill jig, which consists of a parallel gripper, peg-in-hole pins and a back-plate with a recess where a Polydimethylsiloxane cone is placed on top of a force sensor. As the jig approaches the part, the force sensor registers the applied force until it reaches steady state, which indicates full contact between the jig and the part. The peg-in-hole pins then lock into a pre-existing hole, which provides a mechanical reference, and the support plate provides back support during drilling.
Positional accuracy and the repeatability of the system were successfully placed within the specification for accuracy and repeatability (0.1 mm tolerance and 0.2 mm tolerance, respectively).
The drill jig can be integrated into existing robot drilling solutions and modified for specific applications. The integration of the force sensor provides data for engineers to monitor and analyze forces during drilling. The design of the force sensing drill jig is particularly suited to industrial prototype robot drilling end-effectors for small and medium manufacturers.
The key novelties of this drilling jig are in the compact assembly, modular design and inclusion of force sensing and back support features.
