To do this, the monotone curve is firstly drawn, and then without finding the coordinate of the inflexion point, the NC machining path can be obtained by the method of automatic direction control.

• 首先对单调NC轨迹曲线进行绘制，进一步用不求极值点坐标而实现自动控制变向的方法，求出NC加工轨迹；