A method for the evaluation and magnified representation of two-dimensional contouring error

The method of evaluating two-dimensional contouring error between the reference trajectory and the trajectory measured with a cross-grid encoder and magnifying the error is widely used. However, this method has a problem in that the inner cornering error is discontinuously magnified and represented and thus is not accurately detected. Several methods have been proposed to solve this problem, but they have limitations, such as the requirement that an offset value be set or the imposition of conditions on the reference trajectory. Therefore, by calculating errors in the inward direction from a longer trajectory to a shorter trajectory, this paper proposes a new method to continuously magnify and represent the inner cornering error including the corner vertex without the need to set an offset or the imposition of conditions on the reference trajectory. The proposed method was applied to the measurement results at an actual machining center. Consequently, the inner cornering error was continuously magnified and represented, and the error at a corner was accurately calculated using the proposed method.