关键词: 局部非对称平滑过渡, 速度规划混合, 运动学约束, 几何误差约束

Abstract: Aiming at the problem of discontinuous feedrate at the junctions of line segments for the widely used G01 command in CNC machining,a symmetrical smooth transition profile is usually constructed around the corner bisector to reduce the feedrate fluctuation,but this method is relatively inefficient.To fully utilize the capacity of the machine tool,a local asymmetrical smoothing transition method based on feedrate blending was proposed.A seven-phase asymmetrical S-shape acceleration and deceleration and feedrate planning algorithm were designed,which generated a smooth feedrate curve.Then,a time optimization model under kinematic constraints was developed and the kinematic parameters were calculated accordingly.A transition time model based on geometric error constraints was developed,in which the corner geometric error was calculated analytically,the changing process of the error during the transition was proved,and the maximum error was defined.Finally,the blending of the feedrate profile of adjacent line segments at the corner was done before real-time interpolation along the planned trajectory.The experimental results showed that the generated motion profile respected the corresponding constraints of the machine tool,realized the smoothing transition of the corner of the machine tool and improved the machining efficiency.

Key words: local asymmetrical smoothing transition, feedrate planning blending, kinematic constraints, geometric error constraints