ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

The curvature stagnation point curve would degenerate in two straight lines, when the given Ball point was located on the fixed bar and an instantaneous center coincided with a fixed pivot. A random bar laid on the vertical straight line would produce an approximate straight line mechanism. The synthesis formulae and figures of crank linkages solution region on the coordinate plane, based on crank linkages analysis, were presented. Some useful conclusions were obtained by analyzing special points in the solution regions. According to different design demands, the corresponding evaluating functions were adopted in order to calculate the feasible solution region and the optimal mechanism solution automatically. The proposed method was visual and automatic. Both the blindness of choosing optimal mechanism and the lowness of design efficiency were overcome observably.