Gans Šimon, Molnár Ján, Kováč Dobroslav, Kováčová Irena, Fecko Branislav, Bereš Matej, Jacko Patrik, Dziak Jozef, Vince Tibor
Department of Theoretical and Industrial Electrical Engineering, Technical University of Košice, 040 01 Košice, Slovakia.
Sensors (Basel). 2023 Oct 11;23(20):8393. doi: 10.3390/s23208393.
The paper deals with a brief overview of magnetoelastic sensors and magnetoelastic sensors used in general for sensing bending forces, either directly or sensing bent structures, and defines the current state of the art. Bulk magnetoelastic force sensors are usually manufactured from transformer sheets or amorphous alloys. In praxis, usually, a compressive force is sensed by bulk magnetoelastic sensors; however, in this paper, the sensor is used for the measurement of bending forces, one reason being that the effect of such forces is easily experimentally tested, whereas compressive forces acting on a single sheet make buckling prevention a challenge. The measurement of the material characteristics that served as inputs into a FEM simulation model of the sensor is presented and described. The used material was considered to be mechanically and magnetically isotropic and magnetically nonlinear, even though the real sheet showed anisotropic behavior to some degree. A sinusoidal magnetizing current waveform was used in the experimental part of this paper, which was created by a current source. The effects of various frequencies, amplitudes, and sensor geometries were tested. The experimental part of this paper studies the sensors' RMS voltage changes to different loadings that bend the sheet out of its plane. The output voltage was the induced voltage in the secondary coil and was further analyzed to compute the linearity and sensitivity of the sensor at the specific current characteristic. It was found that for the given material, the most favorable operating conditions are obtained with higher frequency signals and higher excitation current amplitudes. The linearity of the sensor can be improved by placing the holes of the windings at different angles than 90° and by placing them further apart along the sheet's length. The current source was created by a simple op-amp voltage-to-current source controlled by a signal generator, which created a stable waveform. It was found that transformer sheet bending sensors with the dimensions described in this paper are suitable for the measurement of small forces in the range of up to 2 N for the shorter sensors and approximately 0.2 N for the longer sensors.
本文简要概述了磁弹性传感器以及一般用于直接或间接检测弯曲力的磁弹性传感器，并阐述了当前的技术水平。块状磁弹性力传感器通常由变压器片材或非晶合金制成。在实际应用中，块状磁弹性传感器通常用于检测压缩力；然而，在本文中，该传感器用于测量弯曲力，原因之一是这种力的效果易于通过实验测试，而作用在单个片材上的压缩力使得防止屈曲成为一项挑战。本文介绍并描述了作为传感器有限元模拟模型输入的材料特性测量。所用材料被认为在机械和磁方面是各向同性且磁非线性的，尽管实际片材在一定程度上表现出各向异性行为。本文实验部分使用了由电流源产生的正弦磁化电流波形。测试了各种频率、幅度和传感器几何形状的影响。本文实验部分研究了传感器的均方根电压对使片材弯曲出其平面的不同负载的变化情况。输出电压是次级线圈中的感应电压，并进一步进行分析以计算特定电流特性下传感器的线性度和灵敏度。结果发现，对于给定材料，在较高频率信号和较高激励电流幅度下可获得最有利的工作条件。通过将绕组孔以不同于90°的角度放置并沿片材长度进一步分开，可以提高传感器的线性度。电流源由一个由信号发生器控制的简单运算放大器电压 - 电流源产生，该信号发生器产生稳定的波形。结果发现，本文所述尺寸的变压器片弯曲传感器适用于测量较小的力，较短的传感器可达2 N，较长的传感器约为0.2 N。
