中文摘要：

对给定机架、直线点位置及方向的机构综合条件，提出了一种铰链四杆直线机构的综合方法，所得到的冉线存给定点为四个无限接近点的近似直线．传统的机构综合方法无法得到给定条件的全部解，因此很难得到性能最优的机构．茸先确定机构解域，将满足要求的无穷多机构解直观地表示在有限坐标平面内，设计者可以直观准确地得到平面内机构的各种属性，因此能在全部机构中选到最优的机构，解决了选取机构的盲目性问题，从而大大缩短了设计周期．

英文摘要：

Given frame points, the point on the expectant straight-line and the direction of the task straight-line, this paper presents a syntbesis method of approximate straigbt-line four-bar linkages, which has four-point contact with its tangent. The traditional synthesis methods are difficult to obtain the optimal mechanism since only parts of the mechanism solutions are synthesized. After solution regions are determined, an infinite number of mechanism solutions satisfied the designers＇ needs can be expressed on a finite coordinate ptane. The mechanism property graphs are displayed to enable the designers to find out all the mechanism types and properties more intuitively for getting the optimal mechanism directly. So the problem of blindness of choosing mechanisms is solved efficiently, and the design period will be shortened.