基于几何矩不变量分析的视觉测力方法

Visual force measurement method based on geometric moment invariants analysis

针对微装配过程中微力测量的问题,提出一种基于几何矩不变量分析的视觉测力方法。利用形状描述算子几何矩不变量构成特征向量,用于描述微夹爪变形前后的形状,推导出几何矩不变量特征向量与受力之间的映射关系,在此基础上建立测力模型及其求解方法;然后建立训练集,输入为在已知受力下微夹爪形状对应的特征向量,输出为已知受力;同样地建立测试集,输入为在未知受力下微夹爪形状对应的特征向量,输出为未知受力;最后支持向量机(SVM)比较测试集与训练集中的特征向量,对测试集的输入进行多类分类,从而测量未知受力。实验结果表明:该方法可以准确而稳定地测量微力。

Aiming at the problem of force measurement in microassembly,a new visual force measurement method based on geometric moment invariants analysis is proposed.The method uses shape descriptor of geometric moment invariants to describe the microgripper shape before and after deformation.Mapping relationship between applied forces and feature vectors of geometric moment invariants is deduced.On this basis,set up force measurement model and its solution.Then,a training set is established,where the input represents the feature vector corresponding to shape of microgripper,and the output represents the corresponding known applied force,respectively.Similarly,a testing set is established,where the input represents the feature vector corresponding to shape of microgripper and the output represents the corresponding unknown applied force,respectively.Finally,a support vector machine(SVM)compares each feature vector in the testing set with those ones in the training set,implements multi-class classification,so as to measure unknown applied force.Experimental results show that the proposed method is accurate and stable.