【作者】 姚世选；

【导师】 常晓明；

【作者基本信息】 太原理工大学 ， 计算机应用技术， 2007， 博士

【摘要】 磁致伸缩直线位移传感器是一种通过检测弹性波激励和接收之间的时间差，得出被测点和接收点之间距离的传感器。在该种传感器系统中，由于永久磁铁磁场和激励磁场的叠加作用，在磁致伸缩线中会产生冲击荷载，由此引起的弹性波将向线的两端传播；弹性波的传播使磁致伸缩线局部变形，在逆磁致伸缩效应的作用下，磁畴偏转将导致检测线圈的输出信号发生变化。本研究通过电磁学、力学等领域的有关计算，构建了该种传感器中弹性波产生、传播和检测的数学模型，采用数学方法描述了电磁能向机械能转换的过程、机械能在传感器细长磁致伸缩线中的传播过程以及机械能向电磁能转换最终形成电信号的过程。论文第二章从磁致伸缩直线位移传感器的基本工作原理出发，分析了该种传感器中所使用的材料Ni-Span-C的磁致伸缩性能和材料特点，探讨了磁致伸缩线中磁畴的磁化问题。研究中进行了相关实验，分析了永久磁铁的空间磁场分布以及永久磁铁和磁致伸缩线的位置关系，研究了在不同强度的外磁场作用下，磁致伸缩线的磁畴发生偏转变化的特点，剖析了磁致伸缩直线位移传感器系统中的电磁现象和特点。论文第三章从驱动脉冲电流产生的周向磁场和永久磁铁磁场的叠加效果之角度，结合磁畴的偏转特点，研究并解明了磁致伸缩直线位移传感器中感应波的产生机理。本研究从磁致伸缩线质点所受荷载的角度，结合弹性动力学的理论，解明了磁致伸缩直线位移传感器中弹性波的产生机理，分析了扭转波的特点；在实验研究中验证了驱动脉冲电流产生的弹性波是上升沿激励的弹性波和下降沿激励的弹性波的合成效果。本研究分析了磁致伸缩线弹性波产生的局部磁场力问题，建立了合扭矩数学模型。根据该种传感器的弹性波传播机理，用数学方法分析和计算了弹性波检测的换能问题。从能量守恒的角度分析了在外磁场影响磁致伸缩线的环境下弹性波信号波形出现不同幅值的问题。结合理论模型，分析了不同激励方式下的弹性波的相位关系。建立了磁致伸缩直线位移传感器驱动脉冲电路设计方案，结合弹性波产生的条件，根据实验数据确定了驱动脉冲电流的参数。论文第四章基于对磁致伸缩直线位移传感器的机理研究，构建了该种传感器的精度测试平台，对传感器系统进行了测试与精度分析，并对国内外生产的部分磁致伸缩线进行了感应波和弹性波的性能测试，给出了分析结果。更多还原

【Abstract】 The magnetostrictive linear position sensor (MLPS) is a kind of sensor that can get the distance between the measured point and the receiving point by measuring the time difference between the excitation and the receipt of elastic waves. In the MLPS system, an impact load can be generated in the magnetostrictive wire due to the joint effect of the permanent magnet and the exciting magnetic field, and at the same time, the arisen elastic waves propagate to two ends of the wire. The propagation of elastic waves can cause a local distortion in the magnetostrictive wire, and under the effect of the inverse magnetostrictive effect, the magnetic domains deflexion brings about the change of output signals of the pick-up coil. Through our calculations, we have established a mathematic model of the generation, propagation and detection of the elastic waves. We have described in a mathematic way the conversion process of electromagnetic energy to mechanical energy, the propagation process of mechanical energy in magnetostrictive wire, the transformation process of mechanical energy into electromagnetic energy and at last its conversion to the voltage signals. In Chapter II, according to the working principle of the MLPS, we have analysed the magnetostrictive performance as well as other characteristics of Ni-Span-C used in MLPS, and we have discussed the magnetization of domains in the magnetostrictive wire. In our study, we have made some experiments, analysed the space distribution of the permanent magnet’s field, studied the characteristics of the magnetic domain’s deflexion in the wire under the effect of different outer magnetic fields, and we have analysed the electromagnetic phenomena in MLPS system.In Chapter III, from the joint effect of the permanent magnet’s field and the circumferential magnetic field induced by the driver pulse current, as well as the deflexion characteristics of the magnetic domains, we have studied the generation mechanism of the induced waves in MLPS. From the point of view of the load on particles in the magnetostrictive wire, in reference to the elastic kinetics theory, we have explained the generation mechanism of the elastic waves in MLPS and analysed the characteristics of the torsional waves. We have proved in our experiments that the elastic waves are the joint effect of the waves drived by positive edge and those by negative edge. We have analysed the local magnetic force of the elastic waves in MLPS and established the resultant torque mathematical model. According to the propagation mechanism of the elastic waves, we have analysed in a mathematic way the energy conversion in the detection of the elastic waves. From the point of view of the conservation of energy, we have analysed the phenomenon that the elastic waves can show different amplitudes under the effect of an outer magnetic field on the magnetostrictive wire. We have designed a driver pulse current circuit in the MLPS. According to the generation condition of the elastic waves and our experiment data, we have determined the parameters of the driver pulse current.In Chapter IV, on the basis of our study about the mechanism of the MLPS, we have made a test platform, tested the performance of the MLPS and given the precision analysis. We have made an analysis of the results after having tested the induced waves and the elastic waves of several magnetostrictive wires made in China and abroad.更多还原