Automated Robotic Deburring of Parts Using Compliance Control

This work presents a method for robotic deburring of two-dimensional planar parts with unknown geometry. Robotic deburring requires “compliancy” and “stiffness” in the robot in the directions tangent and normal to the part, respectively. Compliancy in the tangential direction allows robotic accommodation of tangential cutting forces, while stiffness in the normal direction impedes a robotic response to normal cutting forces. But, to track the part contour, the robot requires compliancy in the normal direction. These conflicting requirements are addressed in this article as two problems: control of the metal removal process and tracking of the part contour. In general, these two problems are coupled; however, here they are separated into a hardware problem and a control problem. A tracking mechanism has been designed and built which incorporates a roller bearing mounted on a force sensor at the robot endpoint. This force sensor is located directly below the cutter and measures the contact forces which are the input to the tracking controller. These contact forces are used not only to calculate the normal vector to the part surface, but also to generate compliancy in the robot. However, the deburring algorithm uses another set of forces (cutting forces generated by the cutter) to produce a stable metal removal process. This deburring control method guarantees compliancy and stiffness in the robot in response to the tangential and normal cutting forces, respectively. Experimental results are given to show the effectiveness of this method for deburring of two-dimensional parts with unknown geometry.