Concept for Robotic Deburring Using Multipass Active Control

Deburring is a critical step in the manufacture of a machined part. The two-pass control concept of this paper removes burrs and produces a consistent chamfer, even with fixture, part, and robot errors. The approach requires a robot for gross positioning of the cutter and an around-the-arm end effector capable of measuring orthogonal force between cutter and workpiece, measuring cutter position with respect to end- effector frame of reference, and actively controlling the cutter-applied orthogonal force. In the first pass, compliance control (orthogonal to workpiece) removes burrs by programming the cutter to act as a low-pass filter on the burrs, where the cutter bandwidth is less than burr time-frequency content, while complying to the fixture, part, and robot errors. In the second pass, chamfer depth variations are smoothed out using chamfer control, where chamfer depth is controlled by computing an estimated real-time chamfer depth, and using this estimate in a feedback loop that varies the cutter-workpiece force to maintain a commanded chamfer depth. The chamfer depth estimator removes repeatable fixture, part, and robot errors by using cutter position measurements from the first pass. Cutting experiments on edges with burrs show that compliance control improved on the force control approach in compensating for burrs, and chamfer control was able to produce a consistent chamfer depth.