Basic study on a Self-tuning method for obtaining highly stable, general-purpose shaft torque sensors

获得高稳定通用轴扭矩传感器的自整定方法的基础研究

• 批准号: 10450160
• 负责人: SASADA Ichiro
• 金额: $ 4.99万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450160/
• 关键词: torque sensor; magnetic head type; zero-level-fluctuation; self-tuning; drift; bridge balance; magnetostrictive effect; 温度安定性; 磁気ヘッド

Magnetostrictive effect inherent in the steel shaft provides noncontacting means of detecting torque applied to the shaft. A problem encountered in this scheme is low accuracy due to magnetic inhomogeneities being inevitable for the case-hardened steel shaft. Our torque sensor consists of induction hardened SNCM steel shaft (25 mmφ) and a magnetic head with a pair of planar figure-of-eight pickup coils embedded in a ferrite core. The objective of this research project is to study factors affecting the accuracy of the torque sensor and to find methods of reducing influence of the factors or to improve accuracy of the torque sensor. Results are summarized below :1. Reduction of zero-level-fluctuationZero-level-fluctuation of the torque sensor is strongly dependent on the balance of the inductance-resistance bridge, which is a main building block of the torque sensor. When the bridge is unbalanced, zero-level-fluctuation is enhanced. A bridge was tuned with a variable resistor connected p … More arallel to one of the pickup coils. With numerical simulation, this tuning condition is found to be unique, that is, global minimum in terms of the root mean square error. However, the tuning condition for a minimum zero-level-fluctuation does not meet, in general, the condition for a minimum offset. We indicated a method to avoid this problems, in which dummy impedance components having averaged values of those of active heads are to be used in the counter branch of the bridge circuit.2. Drift due to ambient temperatureObserving temperature variation of the permeability of each component used in the torque sensor, the most responsible component for the temperature stability is found to be casehardened steel shaft. This is due to the relaxation of compressive stresses in the case region of the shaft due to thermal expansion. Drifts of the torque sensor are observed in a temperature range from 40℃ to 140℃ for various initial offsets. It is found that the drift becomes smaller for smaller initial offset. As an example, temperature drift was -22% for an initial offset of 0.047% normalized to the excitation voltage and was reduced to -7.5% for an initial offset of 0.013%.3. Eddy currents effect on the zero-level stabilitySensing coils induce eddy currents on the surface of the steel shaft. We investigated the influence of the eddy currents on the zero-level stability taking the excitation frequency as a parameter. We found that zero-level perturbs over several period of revolution when the excitation frequency is low and that this phenomenon disappears when the excitation frequency is higher than ten times of the rate of revolution per second. Less

钢轴中固有的磁致伸缩效应提供了检测施加到轴上的扭矩的非接触方式。该方案中遇到的问题是由于表面硬化钢轴不可避免的磁不均匀性而导致的低精度。我们的扭矩传感器由感应淬火SNCM钢轴（25 mmφ）和一个磁头组成，磁头带有一对嵌入铁氧体磁芯的平面8字形拾波线圈。本研究课题的目的是研究影响扭矩传感器精度的因素，并寻找降低这些因素的影响或提高扭矩传感器精度的方法。研究结果如下：1.减小零电平波动扭矩传感器的零电平波动强烈依赖于电感电阻电桥的平衡，电感电阻电桥是扭矩传感器的主要构件。当电桥不平衡时，零电平波动增强。一个电桥用一个可变电阻连接在p ...更多信息 其中一个拾波线圈上。通过数值仿真，证明了该调谐条件是唯一的，即在均方根误差方面是全局最小的。然而，最小零电平波动的调谐条件一般不满足最小偏移的条件。我们提出了一种避免这个问题的方法，即在电桥电路的反分支中使用具有有源磁头平均值的虚拟阻抗元件.由于环境温度引起的漂移观察扭矩传感器中使用的每个组件的磁导率的温度变化，发现对温度稳定性最负责任的组件是表面硬化钢轴。这是由于轴的壳体区域中的压缩应力由于热膨胀而松弛。在40℃ ~ 140℃的温度范围内，对不同的初始偏移量，观测到了扭矩传感器的漂移。研究发现，初始偏移越小，漂移越小。例如，对于标准化到激励电压的0.047%的初始偏移，温度漂移为-22%，并且对于0.013%的初始偏移，温度漂移减小到-7.5%。涡流对零电平稳定性的影响传感线圈在钢轴表面感应涡流。以激励频率为参数，研究了涡流对零电平稳定性的影响。我们发现，当激励频率较低时，零能级扰动会持续几个周期，当激励频率大于每秒转速的10倍时，这种现象消失。少

项目成果

笹田一郎: "磁気工学の基礎と応用 (分担執筆8.4節「トルクセンサ」)"コロナ社(電気学科マグネティックス技術委員会編). 4 (1999)

Ichiro Sasada：“磁工程的基础和应用（合着第 8.4 节“扭矩传感器”）” Corona Publishing（由电气工程系磁学技术委员会编辑）4 (1999)。

Ichiro Sasada,Akira Itoh: "Eddy current effec on the zero-level stability on detecting torque from rapidly rotating steel shafts"Digests of Intermag Conference. Intermag2000(印刷中). 2 (2000)

Ichiro Sasada、Akira Itoh：“涡流对快速旋转钢轴检测扭矩的零级稳定性的影响”Intermag 2000 会议摘要（2000 年）。

真崎義隆、笹田一郎: "磁気ヘッド型トルクセンサにおける外因性ゼロ点変動の低減法"日本応用磁気学会誌. 24巻4-2号(印刷中). 4 (2000)

Yoshitaka Masaki，Ichiro Sasada：“减少磁头型扭矩传感器中的外在零点波动的方法”，日本应用磁学学会杂志，第 24 卷，第 4-2 期（出版中）。

笹田一郎、吉田 誠: "A New Method of Grain Imaging for Highly Gtain-Oriented Silicon Steels"日本応用磁気学会誌. 23巻11号. 2088-2091 (1999)

Ichiro Sasada、Makoto Yoshida：“高取向硅钢晶粒成像的新方法”日本应用磁学学会杂志，第 23 卷，第 11 期。2088-2091 (1999)

Ichiro Sasada, Akira Itoh: "Eddy current effect on the zero-level stability on detecting torque from rapidly rotating steel shafts"Digests of Intermag (International conference on Magnetics). (in press). 1 (2000)

Ichiro Sasada、Akira Itoh：“涡流对快速旋转钢轴检测扭矩的零级稳定性的影响”Intermag 摘要（国际磁性学会议）。