Smooth Cornering Strategy for High Speed CNC Machine Tools With Confined Contour Error

Conventional tool-paths for CNC (computer numerical controlled) machine tools or NC positioning systems are mainly composed of linear motion segments, or so called the G1 commands. Interpolating along linear tool-paths exhibits serious limitations in terms of achieving the desired part geometry and productivity in high-speed machining. Velocity and acceleration discontinuities occur at the junction points of consecutive segments. In order to generate smooth and continuous feed motion, a kinematic corner smoothing algorithm is proposed in this paper, which plans smooth acceleration and jerk profiles around the segment junction to realize continuous velocity transition between consecutive linear segments. The proposed corner-smoothing algorithm eliminates the need for geometry based corner-blending techniques and presents a computationally efficient interpolation scheme. The cornering error is controlled analytically allowing the end-user to control the cornering tolerance. Drive’s acceleration and the jerk limits are fully utilized to minimize overall cornering duration. This delivers a time optimal cornering motion within user specified cornering error tolerances. Simulation studies are used to demonstrate the effectiveness of proposed high-speed cornering scheme.