中文摘要：

为在加工前剔除变形的不合格毛坯或在加工时避免由于定位不够精确而出现余量不足，需在余量约束要求下将毛坯测量数据与CAD模型进行配准。针对此配准问题，提出“二步法”求解：第一步暂不考虑余量约束，用ICP算法进行配准，检查结果是否满足余量要求，满足则退出计算，否则，进行第二步，即考虑余量约束对ICP结果作进一步配准。实验结果表明，该方法能够有效实现毛坯测量数据与CAD模型在余量约束下的配准。

英文摘要：

In order to reject the unqualified blank parts before machining and avoid lack of allow- ance resulting from poor localization during machining, the measured data of blank parts must be a- ligned to the nominal CAD models under the machining allowance constraint. A 2-step algorithm was proposed to solve this alignment problem. Firstly, registration without considering any constraints was performed by the ICP（iterative closest point） algorithm. If the registration results meet the machining allowance requirements, the algorithm terminated; otherwise, the further registration considering al- lowance constraint was performed. Experimental results show that the proposed method is very appro- priate for aligning the measured data of blanks to the nominal CAD models with the machining allow- ance guaranteed.