基于双加速度计的静态角度检测与误差分析  

Static angle detection and error analysis using a pair of 3D accelerometers

作　　者：秦晓丽[1] 谢新武[1,2] 杨健[1] 孙秋明[1] 倪爱娟[1] 田丰[1] 

机构地区：[1]军事医学科学院卫生装备研究所,天津300161 [2]清华大学医学院,北京100084

出　　处：《医疗卫生装备》2015年第8期1-5,9,共6页Chinese Medical Equipment Journal

基　　金：天津市科技支撑计划重点项目(14ZCZDSY00009)

摘　　要：目的:对骨折固定复位训练模拟人的骨折断面位移及角度检测进行研究,解决这一实现模拟人虚实交互的关键和难点。方法:采用微电子机械系统(micro-electro-mechanical-systems,MEMS)的加速度计对骨折断面角度位移量进行静态检测,通过对骨折断面的三维欧拉坐标系建模,推导出静态角度检测的双加速度计二维联合检测方法,并进行了多倾角姿态下的不同角度测量实验。由于该方法存在测量盲区,对可能存在较大误差的测量姿态进行了误差的特性实验,最后对测量结果进行了误差分析。结果:该方法能够有效测量静态角度,除去在盲区的近水平状态,总体测量均方误差为(2.240 3±1.027 2)°,平均误差为(1.809 4±0.895 0)°。根据三维坐标数据的单位正交关系设计的优化算法对多组数据进行计算,得到平均误差可以达到(0.838 78±0.740 0)°,且不受个别盲区数据影响。在待测角度为30°的情况下,误差随着测量平面与水平面夹角的增大而减小,当夹角大于5°时,误差明显下降。结论:零点标定对结果改善有明显效果,灵敏度标定对角度测量结果改善效果有限,传感器精度、信号采集精度都是误差产生的重要原因。该方法是有效的,同时,采用测量多组数据进行优化算法解算能够达到较高的精度,并能有效规避测量盲区。Objective To explore the detection of the fracture section displacement and angle of the simulator for fixation and restitution training. Methods Static detection of the angle and displacement was carried out with the accelerometers of micro-electro-mechanical-systems （MEMS）. A model of fracture section was set up in 3D eulerian coordinate system to de- termine 2D detection method with a pair of accelerometers, and the detection was performed for different angles. The exper- iments were implemented for large errors in some conditions, and error analysis was executed for the detection results. Results For all the conditions except the ones at the blind area, the mean square error was （2.240 3±1.027 2）°, and the mean error was （1.809 4±0.895 0）°. The optimal control algorithm was designed based on the the orthogonality relationship of the 3D accelerometers, and the mean error of all conditions in the experiment reached （0.838 78±0.740 0）% and the measure- ment error was not affected by the result of blind area. When the angle was 30°, the error decrased with the angle increased between the measuring plane and the horizontal plane, and went down sharply with the angle higher than 5°.Conclusion The detection result is significantly improved by zero-point drift compensation, and the sensitivity compensation only has little effects on improving the detection result. The accuracies of the sensor and signal acquisition may be the causes for the errors. The method for angle detection is valid, excepting for the blind area, but the optimal control algorithm based on the the orthogonality relationship of the 3D accelerometers can be designed for improving the precision and removing the data from blind area.

关 键 词：加速度计 角度检测 单位正交优化 误差分析 

分 类 号：TH824.4[机械工程—仪器科学与技术] R683[机械工程—精密仪器及机械]