三维测力装置维间耦合效应试验及解耦方法

Research on Coupling Effect Experiment and Decoupling Method of 3-D Force Measuring Platform

为实现转向架试验台载荷测量功能,提升转向架参数测定精度,设计了多测力传感器并联的三维测力装置,对其测量原理进行理论分析并搭建了惠斯通电桥测量电路。三维测力装置属于切应力传感器,分析表明其测量电路输出电压与载荷有确定的线性关系;进行了三维测力装置单轴加载的静态标定试验,分析了单轴加载的输出特性及其载荷测量的维间耦合效应,发现单轴加载时,加载轴所对应测量电路有线性度良好的电压输出,但非加载轴测量电路同时有较小的电压输出。文中还提出了评价维间耦合效应的耦合度以及基于最小二乘法和BP神经网络的数值解耦方法,并通过试验验证了两种解耦方法的有效性;同时采用正交实验法进行三维测力装置多轴加载试验,单轴测量误差和整体测量误差均没有超过1.5%,测量精度满足测试需求。

In order to measure the force loaded on bogie test bench and improve the measurement accuracy,a three-dimensional(3-D)force measuring platform with multiple force sensors connected in parallel was designed.Its measurement principle was analyzed theoretically and a Wheatstone bridge measurement circuit was built.3-D force measuring platform is a kind of shear stress sensor,and the analysis shows that the output voltage of its mea-surement circuit has a definite linear relationship with the force loaded.The static calibration test of 3-D force measuring platform under uniaxial load was carried out and the output characteristics under uniaxial load and the interdimensional coupling effect of load measurement were analyzed.It finds that under uniaxial load,the voltage output of the measurement circuit corresponding to the loaded axis has good linearity,but the voltage output of the non-loaded axis measuring circuit is small.In this paper,the coupling degree evaluating coupling effect between dimensions and the numerical decoupling method based on least square method and BP neural network were also proposed,and their effectiveness was verified by experiments.At the same time,the orthogonal method was used to carry out the multi-axis loading test of the three-dimensional force measuring platform.The results show that the single-axis measurement error and the overall measurement error are not more than 1.5%,thus the measurement accuracy meets the test requirements.