Coordinated contour following control for machining operations-a survey

Contour following is one of the most critical requirements in multi-axial machining operations. In these operations, a tool path is defined to specify where material ought to be removed from the part being machined. The tool must precisely follow this contour as any deviations from the contour would result in unintentional material removal. In the paper, the main control approaches for this class of problems are reviewed and surveyed, highlighting the coordination aspect of these problems. These can be roughly categorized into time trajectory based methods and non-time based control methods. The former includes the so called "cross-coupled" control, and modifications. The latter includes the "velocity field control" approach.