Tool Path Planning Using the Relationship between Cornering Error and Kinematic Constraint Values

The kinematic constraints used in a computerized numerical control (CNC) interpolator are one of the main factors determining a machine tool’s machining accuracy. The CNC generates velocity profiles by applying kinematic constraints such as jerk and acceleration. Therefore, changing the kinematic constraints values can adjust the cycle time and cornering error. This study proposes a method to adjust the kinematic constraint values. First, the relationship between CNC kinematic constraints and cornering errors were analyzed. The relationship between the kinematic constraints and the cornering error was expressed as an analytical solution. Kinematic constraint values that satisfy specific cornering error values were selected using the analytical solution of cornering error. Finally, a method was devised to apply the appropriate kinematic constraint values to each machining section within a part program. The analytical solutions for cornering errors and using different machining segments to control cornering errors were verified using tool path generation simulation.