ABSTRACT
Automating machining through robots is the way forward due to many valid reasons such as lack of skilled machinists and lesser productivity and downtime. However, there are still many challenging issues, such as dealing with curved surfaces with a lack of prior knowledge regarding the workpiece. Ensuring proper alignment between the tool and workpiece is of utmost importance during the machining process. Nonetheless, when confronted with a workpiece featuring curved surfaces, attaining optimal perpendicularity of the tool with respect to the surface presents several challenges. Some work has been done by researchers to deal with this kind of trajectory-tracking issue in robotic machining. Most of the existing approaches are not very suitable due to inaccuracies and usually require high computation power. In this chapter, we present a simple but efficient way of dealing with curved surfaces during polishing and grinding. In comparison to other techniques, our proposed scheme does not require a three-dimensional computer-aided model (3D CAD model) or any information about the surface geometry to start with. The proposed scheme utilizes a passively compliant tool holder and a pose correction control algorithm employing a six-axis force sensor. The scheme automatically adjusts the tool to stay normal on the surface during machining. The scheme has been validated by conducting several experiments using a 6-DOF robotic manipulator.
