屏幕拟合法在平面连杆机构离散点轨迹综合中的应用

Application of screen imitating in the path synthesis of plane linkage mechanism

屏幕拟合法是基于轨迹图谱、图形逼近理论及计算机可视化技术的一种平面连杆机构离散点轨迹综合的新方法。用三次B样条曲线将离散点拟合成连续的目标曲线。通过连杆曲线图谱 ,先初选一个与目标曲线形状接近的连杆曲线 ,通过调整连杆机构的尺寸参数和图形变换 ,改变连杆曲线的形状和位置 ,使其与目标曲线逐渐逼近 ,直到用肉眼观察完全重合为止。将连杆机构与目标曲线同时放大 ,在放大状态下再次调整机构参数和对图形进行变换 ,使两条曲线继续逼近 ,如果拟合误差满足精度要求则输出设计结果 ,否则重复上述过程 ,直到满足精度要求为止。

Screen imitating is a new synthetic method for generating coupler curves of plane linkage mechanisms based on path atlas and graphics approach with visualization technology of computer.The dispersed points are imitating to continuous aim curve with cubic B- spline curves. From the path atlas of coupler-curves, one optimized is elected which is similar to the object curve. Until the two curves are closely approached by changing the shape and position of the linkage mechanism.then the coupler-curve and object curve are amplified simultaneously,and in this cases, the two curves are approached much close. If the imitating errors are in allowed band then output design result, otherwise, the process above will be repeated until determined precision is satisfied. It can satisfy any shape and precision requirement of path synthesis. 