平面闭式运动链简图自动绘制的最大环路法

机构运动链结构简图的自动绘制，直接关系到机构设计的效率与可靠性。在对平面闭式机构运动链的拓扑特性研究基础上，基于缩杆邻接矩阵，提出一种运动链结构简图自动绘制的最大环路方法。此方法采用广度优先生成树算法获得运动链的独立回路，并通过独立回路的加减运算得到最大可行外环。根据回路关系逐步修正最大可行外环，使各独立回路成为其非交叉规范化内环。在运动链结构简图绘制过程中，根据外环和内环情况，将运动链中的运动副布置在由外往内的同心圆内接正多边形的顶点上，使绘制的运动链简图规范、美观。在对这种基于外环与内环关系的简图自动绘制算法研究过程中，借助多个机构实例进行说明。研究与应用结果表明，最大环路法具有实现简单、方法完备的特点，适用于多杆多自由度平面闭式运动链结构简图的自动绘制，应用于机构设计中，可极大地提高设计效率。

Maximal Loop Method of Automatic Sketching of Planar Closed Kinematic Chains

Automatic sketching of mechanism kinematic chains affects directly the efficiency and reliability of mechanism design. On the basis of a study of the topologic characteristics of planar closed kinematic chains, the maximal loop method is presented, based on contracted link adjacency matrix, to complete automatic sketching of planar closed kinematic chains. Independent loops of kinematic chains are derived by using the breadth-first spanning tree algorithm, based on which the maximal feasible loop is achieved by means of independent loops add-subtract operation. The maximal feasible loop is step by step modified in accordance with the loop relationships so that all independent loops become its normalized non-crossing inner loops. In the process of automatic sketching of kinematic chains, the joints of kinematic chain are located, from outer lane to inner lane, on the vertices of inscribed regular polygon of the concentric circles on the basis of the outer and inner loops’ relationships. As a result, the sketches of the kinematic chains appear to be normal and beautiful. The development process of this algorithm based on the outer loop and the inner loops relationships is demonstrated with the aid of several mechanism examples. The study and the application of the maximal loop method show that it is simple and comprehensive. And it is applicable for the automatic sketching of planar closed kinematic chains with multiple links and multiple degrees of freedom. It can greatly raise the efficiency in mechanism design.