数控转台拉弯机切点跟踪轨迹生成算法

建立了拉弯过程运动关系几何模型，采用数值计算的方法推导了任意外凸模具外形曲线切点跟踪轨迹的求解算法。得出了切点坐标与转台转角的关系曲线。为拉弯机的自动切点跟踪提供了准确的控制依据。并根据轨迹上最大切线斜率最小的优化目标，以侧压轮运动范围、主缸最大允许摆角及补拉夹头与转台中心的距离为约束条件，计算出模具的最佳安装位置。运用VC编制了通用计算程序，计算结果表明：该算法稳定，适合于各种拉弯模具外形曲线，计算效率及精度高。

ALGORITHM OF GENERATING THE TRACKING LOCUS OF THE TANGENT POINT FOR NC ROTARY STRETCH-BENDING FORMER

A geometric model of the movement relation in the forming process is established. A numerical solution that can calculate the locus of the tangent point of any convex curve shape of die is deduced, and the relation curves of the location of the tangent point and the rotation angle of the rotary is obtained, which provides the precise controlling foundation for tracking the tangent point automatically. And based on the optimum target that the maximum slope of the tangent point must be minimum, a more reasonable mounting location of the die is worked out, which satisfies the constraint conditions of the movement range of the lateral pressure wheel, the maximum swing angle of the main cylinder, and the distance from the collet of the supplementary cylinder to the center of the rotary. Meanwhile a general calculation program has been developed with VC. The result shows that the algorithm is steady, which has high efficiency and precision, and is adaptive to convex dies.