Objective To study the key technologies for automatic thickness measurement of soft tissues,and to design the instrument for thickness measurement and verify its feasibility and accuracy by experiments. Methods An experimental system for measuring thickness was designed. The feedback and control of the measurement structure were achieved by the slowing direct-current motor with an encoder. The relationship between master motion and slave motion was built according to the transmission between internal structures. Finally,experiments for thickness measurement were conducted,and,the error size and distribution were analyzed by comparing results of the experiment group with those of the contrast group. Results 27 pairs of thickness data were produced from 9 groups of experiments. The average error was -0.07 mm and the variance was 0.03 mm2. There was a small error fluctuation when the data was divided by experiment time,while the error fluctuation was obvious when divided by thickness. Conclusions The instrument for thickness measurement has been shown feasible with a small average error for all data,in spite of the existence of errors. The experiment time, which determines the initial measurement position, has great influence on the result. However, different thickness, which means different opening angle of the instrument,shows negligible effect on the measuring data.%目的 研究自动测量软组织厚度的关键技术,设计一种自动测量组织厚度的器械,通过实验验证其可行性及准确性.方法 设计测厚实验系统,采用直流减速编码器电机实现对测量结构的反馈和控制,按照结构内部的传动关系建立主从运动量间的关系式,即电机转轴转动圈数与器械前端所夹组织厚度的关系,从而实现测厚功能.根据实验组与对照组的结果分析测试实验系统的误差与分布情况.结果9组实验共产生27对厚度数据,其误差平均值为-0.07 mm,方差为0.03 mm2.按实验次数分组,其组内误差波动较小;按厚度值分组,其组内误差波动较大.结论 采用该器械测量厚度是可行的,但还存在一定误差;实验批次决定了器械测量的初始位置,对测量结果影响较大;不同厚度值对应器械前端不同的开口角度,对测量结果影响较小.
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