利用刚性体识别的三维尺寸标注完备性检查

Completeness Testing of Three-Dimensional Dimensions Using Rigid Solid Recognition

为了实现有循环约束的尺寸完备性的自动检查,将循环约束的判断问题转化为刚性体的识别问题,提出一种基于刚性体识别的三维尺寸完备性检查方法.首先引入定位元的概念,并建立了基于恒定度求交的定位元组选择机制;然后以定位元组为基准,提出基于轨迹相交法的刚性体识别方法;再通过向刚性体内部添加虚尺寸,利用等价定位元组的固定实现了刚性体的合并;最后根据刚性体的合并状态和尺寸的使用状态,分析了尺寸的4种完备性状态.以一个有循环约束和冗余尺寸的模型为例演示了尺寸完备性的检查过程,验证了该方法的有效性和稳定性.

In order to achieve the automation of dimensioning completeness testing with cyclic constraints,determination of the cyclic constraints is converted into the recognition problem of rigid solid （RS）, and a methodof three-dimensional dimensioning completeness testing based on rigid body recognition is proposed. Firstly, aconcept of located primitive（LP） is introduced, and the selection mechanism of LP group is established based onthe intersection of LP＇s degree of invariance. Subsequently, on the basis of LP group, the recognition method ofRSs is proposed based on the method of locus intersection. And then, the RSs are merged by using the fixation ofthe equivalent group of LPs, with the addition of virtual dimensions. Four types of dimensions completenessstates are analyzed according to the merged status of RS and the used status of dimensions. Finally, a model withcyclic constraints and redundant dimensions is taken as an example to demonstrate the completeness testing ofdimensions, and verify the effectiveness and stability of the approach.