Design of a device for measuring the centroid of artificial limb

Abstract

AIM: To measure the centroid parameters of artificial limb, so as to assure its design quality.

METHODS: The counterforce was measured by weighing sensor based upon static weighing technique, and the data were sent to the data acquisition and processing system for calculating the quality and centroid coordinate of the artificial limb. A homogeneous cuboid was taken as the subject to measure its quality and centroid. At the same time, it can be used to check up the measurement error such as the processing error of the device and the sensor accuracy error and so on.

RESULTS: The absolute error of centroid was ΔXc=–0.313 0 mm, ΔYc=–0.108 6 mm, ΔZc=–0.234 6 mm, and the relative error was Xc%=2.65%, Yc%=3.77%, Zc%=4.82%.

CONCLUSION: ①The relative error is less than 5% allowed by the engineering error, so the result is confident by the measurement of the device. ②The designer could make sure that the quality and centroid of the artificial limb are approximate to the healthy one. ③It is very significant to promote the design of the artificial limb whose centroid is difficult to measure for the complicated shape. ④The device can meet the challenge by its high precision, and it is simple and exact to measure. Moreover, it becomes a experiment table which can be used to both measurement and research. *

Chen RJ, Shen LX, Yu HL, Li MY, Bu WW, Ding H.Design of a device for measuring the centroid of artificial limb. Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(4):700-702(China)
[www.zglckf.com/zglckf/ejournal/upfiles/08-4/4k-700(ps).pdf]

摘要
目的：测量假肢的质心参数，为假肢设计提供数据保证。
方法：基于静态称重技术，利用称重传感器测量支反力，并将其测量数据传输到数据采集和处理系统，计算出假肢的质量与质心坐标。测量时，取一矩形均质长方体构件为对象测其质量和质心参数（由于质量易测，因此主要分析质心的测量），同时作为标准件来检验该装置的测量误差，其中该误差包括装置的加工误差，和传感器的测量精度误差等。
结果：实验测量得到的质心绝对误差为ΔXc=–0.313 0 mm,ΔYc=–0.108 6 mm,ΔZc=–0.234 6 mm；相对误差为：Xc%= 2.65%，Yc%=3.77%，Zc%=4.82%。
结论：①测试相对误差均小于工程误差允许的5%，用该装置测试的假肢质心位置是可信的。②为假肢设计者提供依据，使得假肢的质量和质心与健肢各部分大体一致。③对于像假肢这样形状复杂物体的质心测定，提升假肢设计水平具有重要意义。④该装置测量便捷、准确，精度满足使用要求，是一个兼具测试，研发双重功能的实验平台。
关键词：假肢；质心；传感器；测量

陈仁建，沈力行，喻洪流，郦鸣阳，卜薇薇，丁皓．假肢质心测定装置的研制[J].中国组织工程研究与临床康复，2008，12(4):700-702 [www.zglckf.com/zglckf/ejournal/upfiles/08-4/4k-700(ps).pdf]