Tool path correction for robotic deburring using local non-rigid 3D registration

The presence of residual burrs on the surface of workpieces not only affects the surface quality but also reduces their performance. The position and orientation of the cutting tool in the deburring process are crucial for effective burr removal. Due to the interference caused by the burrs uncertainty or the manufacturing deformation, the off-line path from the workpiece CAD model is difficult to ensure the processing quality in robotic deburring. To solve that, a correction strategy for the robotic deburring paths is developed based on a visual feedback model registration. Firstly, by applying CAM software, the nominal tool path is generated from the workpiece CAD model. Secondly, by conducting global rigid registration, followed by a local non-rigid registration with burr height constraint, the transformation matrix between the measuring data and CAD model can precisely calculate to mitigate the impact of local shape deformations on registration precision. Finally, the actual tool path is obtained by using the transformation matrix to correct the nominal tool path. Comparisons results show that: for the proposed method, the maximum contour deviation between the corrected path and reconstructed theoretical is less than 0.2mm, while the chamfer size remains relatively uniform in real machining with minimal variation ranging from 0.5mm to 0.8mm, which demonstrates that such method can effectively address the issue of deviation in robot deburring paths caused by workpiece deformation.