基于磁敏电阻的磁力计设计
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摘要
磁场尤其是弱磁场(如大地磁场)精确测量技术的应用,已经深入到工业、农业、国防以及生物、医学、宇航、星际研究等各个部门,各种磁力计应运而生,主要有磁通门式、质子旋进式、光泵式、超导式磁力计等。虽然这些磁力计的精度较高,但是成本较高、体积较大、组成复杂、可靠性较差,不能满足低成本、微型化、设计简单可靠的需要。并且一般都是一维磁力计,如果要进行磁场的三维测量,至少需要三个(组)探头,导致组成更加复杂、体积更大、价格昂贵。
本文在深入分析各向异性磁敏电阻(Anisotropic Magneto Resistance,AMR)基本原理的基础上,提出了基于各向异性磁敏电阻的磁力计设计方案,能够对磁场进行三维测量,具有组成简单、体积小巧、成本较低、安全可靠等特点,具体研究工作包括:
(1)分析各向异性磁敏电阻基本原理及结构;
(2)磁阻测磁、倾角测量部分的设计、制作及调试;
(3)控制核心及外围部件的电路设计、制作及调试;
(4)μC/OSⅡ实时操作系统分析、在MSP430单片机上的移植以及基于μC/OSⅡ的各功能任务模块的程序编写;
(5)基于MFC的上位机软件编写;
(6)样机制作、系统整机调试、误差补偿分析及实验结果分析。
The applications of precision measurement technology of magnetic field particularly weak magnetic field (such as the earth magnetic field), have stretched into industry, agriculture, national defense, as well as biology, iatrology, aerospace, space research, and other departments. Various magnetometers have emerged, mainly are the fluxgate magnetometer, proton precession magnetometer, optically pumped magnetometer, the superconducting magnetometer, and in the research and testing phase of the solid electron spin resonance magnetometer, atomic magnetometer. Although the accuracy of these magnetometer relatively high, but they are high cost, large size, complex composition, poor reliability, unable to meet low-cost, low-power, miniaturized and the need for a simple and reliable design. Those magnetometer are generally one-dimensional magnetometer, if we carry out the three-dimensional magnetic field measurement, needs at least three (groups) of the probe, leading to the formation of more complex, larger, higher price.
As semiconductor technology develops rapidly, anisotropy magnetic resistance (AMR) sensor came into being. The sensor is small in size, low power consumption, high sensitivity, high reliability, strong anti-jamming capability, temperature stability, and strong resistance to harsh environment, the wide frequency bandwidth, easy in adaption to digital circuit and easy to install. We design and product a magnetometer based on the 3-D AMR sensor.
In the hardware design, using AMR HMC1001/1002 to form a triaxial magnetoresistive sensor for measuring magnetic field strength, its output has good linearity within±0.2mT, and measurement bandwidth can be up to 5 MHz. Biaxial angle inclinometer SCA100T is used to measure the magnetometer’s roll angle and pitch angle in order to achieve the magnetometer coordinate transformation and functional expansion. Take into account such as system’s requirements of accuracy and precision, a 16-bitsΣ-ΔA/D converter, AD7798, is chosen to convert the output voltage of AMRs. Another AD7798 is chosen to convert the output voltage of angle sensor SCA100T. Micro Control Unit (MCU) MSP430F149 is used in this design, which has a 16 R1SC structure. With the 16 CPU registers and the constant generator, the code can be made to the highest efficiency. And it also integrates the JTAG interface, which can directly program the Flash memory. A liquid crystal display and a keyboard are used as Human Computer Interface (HCI) to achieve the magnetometer’s settings and operation. Measurement results are kept in the expanded FLASH memory. A USB chip is selected to communicate with PC to transmit the measurement results. The software in PC can get the measurement results into an Excel table directly, easy to deal with them. Furthermore, in order to meet the power supply voltage requirements of different modules, specifically power module is designed to output 3.3 V, 5V,±12V.
In software design, the single-chip microcomputer’s software is a design of the multi-task which based onμC/OS-II, a Real-Time Operating System (RTOS).μC/OS-II is a source code open, ROM-based operating, reductable, preemptive real-time multi-task kernel with a high degree of portability, high reliability, robustness and security, particularly suited to the microprocessor and microcontrollers. It can perform as well as many commercial real-time operating systems.μC/OS-II is the first background process program that the MCU runs after it stared. It works as the main management control procedure to manage the resources of the system and schedule various tasks. And user’s application that run on it are called task. In accordance with the needs of the various tasks,μC/OS-II undertakes the task such as resources management, task scheduling, information management, exception handling and so on. As each task has a unique priority, therefore, according to the priority and state of each task,μC/OS-II dynamically switchs between the various tasks, in order to ensure real-time. Independent preparation of the various tasks, inter-task communication and synchronization mechanisms which ensure coordination between the mission, reduce the complexity of the procedures the workload of the program design to a large extent, but also reduces the possibility of error, make procedures more reliable, easier maintain. PC software design using MFC programming under Visual C++6.0 and the measurement results stored in the FLASH can be transmitted into an Excel spreadsheet through COM interface.
The system overall test shows that the magnetometer can complete the magnetic field acquisition and get high precision measurements through software processing such as error compensation. Besides, it also shows that the magnetometer can store, display, transmit the measurement results and with the feature of simple composition, low power, low cost, small size, safe and reliable.So we can say the design has achieved the expected objective.
本文在深入分析各向异性磁敏电阻(Anisotropic Magneto Resistance,AMR)基本原理的基础上,提出了基于各向异性磁敏电阻的磁力计设计方案,能够对磁场进行三维测量,具有组成简单、体积小巧、成本较低、安全可靠等特点,具体研究工作包括:
(1)分析各向异性磁敏电阻基本原理及结构;
(2)磁阻测磁、倾角测量部分的设计、制作及调试;
(3)控制核心及外围部件的电路设计、制作及调试;
(4)μC/OSⅡ实时操作系统分析、在MSP430单片机上的移植以及基于μC/OSⅡ的各功能任务模块的程序编写;
(5)基于MFC的上位机软件编写;
(6)样机制作、系统整机调试、误差补偿分析及实验结果分析。
The applications of precision measurement technology of magnetic field particularly weak magnetic field (such as the earth magnetic field), have stretched into industry, agriculture, national defense, as well as biology, iatrology, aerospace, space research, and other departments. Various magnetometers have emerged, mainly are the fluxgate magnetometer, proton precession magnetometer, optically pumped magnetometer, the superconducting magnetometer, and in the research and testing phase of the solid electron spin resonance magnetometer, atomic magnetometer. Although the accuracy of these magnetometer relatively high, but they are high cost, large size, complex composition, poor reliability, unable to meet low-cost, low-power, miniaturized and the need for a simple and reliable design. Those magnetometer are generally one-dimensional magnetometer, if we carry out the three-dimensional magnetic field measurement, needs at least three (groups) of the probe, leading to the formation of more complex, larger, higher price.
As semiconductor technology develops rapidly, anisotropy magnetic resistance (AMR) sensor came into being. The sensor is small in size, low power consumption, high sensitivity, high reliability, strong anti-jamming capability, temperature stability, and strong resistance to harsh environment, the wide frequency bandwidth, easy in adaption to digital circuit and easy to install. We design and product a magnetometer based on the 3-D AMR sensor.
In the hardware design, using AMR HMC1001/1002 to form a triaxial magnetoresistive sensor for measuring magnetic field strength, its output has good linearity within±0.2mT, and measurement bandwidth can be up to 5 MHz. Biaxial angle inclinometer SCA100T is used to measure the magnetometer’s roll angle and pitch angle in order to achieve the magnetometer coordinate transformation and functional expansion. Take into account such as system’s requirements of accuracy and precision, a 16-bitsΣ-ΔA/D converter, AD7798, is chosen to convert the output voltage of AMRs. Another AD7798 is chosen to convert the output voltage of angle sensor SCA100T. Micro Control Unit (MCU) MSP430F149 is used in this design, which has a 16 R1SC structure. With the 16 CPU registers and the constant generator, the code can be made to the highest efficiency. And it also integrates the JTAG interface, which can directly program the Flash memory. A liquid crystal display and a keyboard are used as Human Computer Interface (HCI) to achieve the magnetometer’s settings and operation. Measurement results are kept in the expanded FLASH memory. A USB chip is selected to communicate with PC to transmit the measurement results. The software in PC can get the measurement results into an Excel table directly, easy to deal with them. Furthermore, in order to meet the power supply voltage requirements of different modules, specifically power module is designed to output 3.3 V, 5V,±12V.
In software design, the single-chip microcomputer’s software is a design of the multi-task which based onμC/OS-II, a Real-Time Operating System (RTOS).μC/OS-II is a source code open, ROM-based operating, reductable, preemptive real-time multi-task kernel with a high degree of portability, high reliability, robustness and security, particularly suited to the microprocessor and microcontrollers. It can perform as well as many commercial real-time operating systems.μC/OS-II is the first background process program that the MCU runs after it stared. It works as the main management control procedure to manage the resources of the system and schedule various tasks. And user’s application that run on it are called task. In accordance with the needs of the various tasks,μC/OS-II undertakes the task such as resources management, task scheduling, information management, exception handling and so on. As each task has a unique priority, therefore, according to the priority and state of each task,μC/OS-II dynamically switchs between the various tasks, in order to ensure real-time. Independent preparation of the various tasks, inter-task communication and synchronization mechanisms which ensure coordination between the mission, reduce the complexity of the procedures the workload of the program design to a large extent, but also reduces the possibility of error, make procedures more reliable, easier maintain. PC software design using MFC programming under Visual C++6.0 and the measurement results stored in the FLASH can be transmitted into an Excel spreadsheet through COM interface.
The system overall test shows that the magnetometer can complete the magnetic field acquisition and get high precision measurements through software processing such as error compensation. Besides, it also shows that the magnetometer can store, display, transmit the measurement results and with the feature of simple composition, low power, low cost, small size, safe and reliable.So we can say the design has achieved the expected objective.
引文
【1】 毛振珑,磁场测量,北京:原子能出版社,1985
【2】 李大明,磁场的测量,北京:机械工业出版社,1993
【3】 唐统一,近代电磁测量,北京:中国计量出版社,1992
【4】 阿法拉谢耶夫等,磁场参数测量器具,北京:科学出版社,1983
【5】 Honeywell,1- and 2-Axis Magnetic Sensors HMC1001/1002 HMC1021/1022 ,http://www.honeywell-sensor.com.cn,2004
【6】 Honeywell,HANDLING SENSOR BRIDGE OFFSET,http://www.honeywell-sensor.com.cn,2005
【7】 J. Kubik,J. Vcelak, P. Ripka,On cross-axis effect of the anisotropic magnetoresistive sensors ,Sensors and Actuators A: Physical ,Volume 129, Issues 1-2, 24 May 2006, Pages 15-19
【8】 Bharat B.Pant,Mike Caruso,Magnetic sensor cross-axis effects, http://www.honeywell-sensor.com.cn,2005
【9】 Honeywell,CROSS AXIS EFFECT FOR AMR MAGNETIC SENSORS ,http://www.honeywell-sensor.com.cn,2004
【10】 Honeywell,APPLICATIONS OF MAGNETIC POSITION SENSORS,http://www.honeywell-sensor.com.cn,2004
【11】 Honeywell,SET RESET FUNCTION FOR MAGNETIC SENSORS,http://www.honeywell-sensor.com.cn,2004
【12】 田跃 王元玮 和文国 裴励,当代磁敏电阻型传感器的发展与应用,传感器世界,1996(8)
【13】 白慧 段军政 王红雨等,基于薄膜磁阻传感器的微弱磁场测量仪的硬件设计,现代电子技术.2003(23)
【14】 袁智荣,三轴磁航向传感器的全姿态误差补偿,传感器技术,2003, 22(9)
【15】 林东 陈新,三维空间磁场结构数学模型及磁场方式三维定位装置,福州大学学报(自然科学版),2003,31(2)
【16】 郭志友 孙慧卿,磁传感器的非线性误差修正技术,传感器技术,2004(5)
【17】 任来平 赵俊生 侯世喜,磁偶极子磁场空间分布模式,海洋测绘,2002(2)
【18】 胡海滨 林春生,基于共轭次梯度法的非理想正交三轴磁传感器的修正,数据采集与处理,2003(3)
【19】 林春生 向前 龚沈光,三轴磁强计正交误差分析与校正,探测与控制学报,2006,27(2)
【20】 邓正隆,惯性导航原理,哈尔滨:哈尔滨工业大学出版社,1994
【21】 VTI TECHNOLOGY,THE SCA100T DUAL AXIS INCLINOMETER SERIES DATASHEET,http://www.vti.fi
【22】 ANALOG DEVICE,AD7798/7799 DATASHEET ,http://www.analog.com,2005
【23】 ANALOG DEVICE,Interfacing to High Speed ADCs via SPI,http://www.analog.com,2005
【24】 Texas Instruments Incorporated,MSP430x1xx User’s Guid,http://www.ti.com,2006
【25】 Texas Instruments Incorporated, MSP430x14x MIXED SIGNAL MICROCONTROLLER,http://www.ti.com,2004
【26】 沈建华等,MSP430 系列 16 位超低功耗单片机原理与应用,北京:清华大学出版社,2004
【27】 魏小龙,MSP430 系列单片机接口技术及系统设计实例,北京:北京航空航天大学出版社,2002
【28】 胡大可,MSP430 系列 16 位超低功耗单片机原理与应用,北京:北京航空航天大学出版社,2001
【29】 胡大可,MSP430 系列单片机 C 语言程序设计与开发,北京:北京航空航天大学出版社,2003
【30】 张晞等,MSP430 系列单片机实用 C 语言程序设计,北京:人民邮电出版社,2005
【31】 秦龙,MSP430 单片机常用模块与综合系统实例精讲,北京:电子工业出版社,2007
【32】 SAMSUM ELCTRONICS , K9F2808U0C datasheet ,http://www.samsung.com,2005
【33】 Future Technology Devices Intl. Ltd.,FT245BM USB FIFO ( USB - Parallel ) I.C.,http://www.ftdichip.com,2005
【34】 Future Technology Devices Intl. Ltd.,D2XX Programmer's Guide,http://www.ftdichip.com,2006
【35】 MAXIM datasheet,DS1302 Trickle-Charge Timekeeping Chip,Http://www.maxim.com,2005
【36】 高光天,传感器与信号调理器件应用技术,北京:科学出版社,2002
【37】 施因果德编著 徐德炳译,传感器的接口与信号调理电路,北京:国防工业出版社,1984
【38】 MAXIM datasheet, MAX761 12V High-Efficiency,Low IQ, Step-Up DC-DC Converters,Http://www.maxim.com,2005
【39】 MAXIM datasheet,MAX765 -12V High-Efficiency, Low IQ DC-DC Inverters,Http://www.maxim.com,2005
【40】 谭浩强,C 程序设计,北京:清华大学出版社,1991
【41】 Jean J.Labrosse,嵌入式实时操作系统 μC/OSⅡ(第二版),北京:北京航空航天大学出版社,2003
【42】 任哲 潘树林 房红征,嵌入式操作系统基础 μC/OSⅡ和 Linux,北京:北京航空航天大学出版社,2006
【43】 郑莉 董渊 张瑞丰,C++语言程序设计(第三版),北京:清华大学出版社,2003
【44】 郑阿奇,Visual C++教程,北京:清华大学出版社,2005
【45】 侯俊杰,深入浅出 MFC(第 2 版),武汉:华中科技大学出版社,2001
【46】 李志宏 余忠民,怎样正确理解和运用标准偏差 δ,机械开发,2000(2)
【47】 叶昌建,标准偏差 δ 的意义及在生产中的应用,计量技术,1995(8)
【2】 李大明,磁场的测量,北京:机械工业出版社,1993
【3】 唐统一,近代电磁测量,北京:中国计量出版社,1992
【4】 阿法拉谢耶夫等,磁场参数测量器具,北京:科学出版社,1983
【5】 Honeywell,1- and 2-Axis Magnetic Sensors HMC1001/1002 HMC1021/1022 ,http://www.honeywell-sensor.com.cn,2004
【6】 Honeywell,HANDLING SENSOR BRIDGE OFFSET,http://www.honeywell-sensor.com.cn,2005
【7】 J. Kubik,J. Vcelak, P. Ripka,On cross-axis effect of the anisotropic magnetoresistive sensors ,Sensors and Actuators A: Physical ,Volume 129, Issues 1-2, 24 May 2006, Pages 15-19
【8】 Bharat B.Pant,Mike Caruso,Magnetic sensor cross-axis effects, http://www.honeywell-sensor.com.cn,2005
【9】 Honeywell,CROSS AXIS EFFECT FOR AMR MAGNETIC SENSORS ,http://www.honeywell-sensor.com.cn,2004
【10】 Honeywell,APPLICATIONS OF MAGNETIC POSITION SENSORS,http://www.honeywell-sensor.com.cn,2004
【11】 Honeywell,SET RESET FUNCTION FOR MAGNETIC SENSORS,http://www.honeywell-sensor.com.cn,2004
【12】 田跃 王元玮 和文国 裴励,当代磁敏电阻型传感器的发展与应用,传感器世界,1996(8)
【13】 白慧 段军政 王红雨等,基于薄膜磁阻传感器的微弱磁场测量仪的硬件设计,现代电子技术.2003(23)
【14】 袁智荣,三轴磁航向传感器的全姿态误差补偿,传感器技术,2003, 22(9)
【15】 林东 陈新,三维空间磁场结构数学模型及磁场方式三维定位装置,福州大学学报(自然科学版),2003,31(2)
【16】 郭志友 孙慧卿,磁传感器的非线性误差修正技术,传感器技术,2004(5)
【17】 任来平 赵俊生 侯世喜,磁偶极子磁场空间分布模式,海洋测绘,2002(2)
【18】 胡海滨 林春生,基于共轭次梯度法的非理想正交三轴磁传感器的修正,数据采集与处理,2003(3)
【19】 林春生 向前 龚沈光,三轴磁强计正交误差分析与校正,探测与控制学报,2006,27(2)
【20】 邓正隆,惯性导航原理,哈尔滨:哈尔滨工业大学出版社,1994
【21】 VTI TECHNOLOGY,THE SCA100T DUAL AXIS INCLINOMETER SERIES DATASHEET,http://www.vti.fi
【22】 ANALOG DEVICE,AD7798/7799 DATASHEET ,http://www.analog.com,2005
【23】 ANALOG DEVICE,Interfacing to High Speed ADCs via SPI,http://www.analog.com,2005
【24】 Texas Instruments Incorporated,MSP430x1xx User’s Guid,http://www.ti.com,2006
【25】 Texas Instruments Incorporated, MSP430x14x MIXED SIGNAL MICROCONTROLLER,http://www.ti.com,2004
【26】 沈建华等,MSP430 系列 16 位超低功耗单片机原理与应用,北京:清华大学出版社,2004
【27】 魏小龙,MSP430 系列单片机接口技术及系统设计实例,北京:北京航空航天大学出版社,2002
【28】 胡大可,MSP430 系列 16 位超低功耗单片机原理与应用,北京:北京航空航天大学出版社,2001
【29】 胡大可,MSP430 系列单片机 C 语言程序设计与开发,北京:北京航空航天大学出版社,2003
【30】 张晞等,MSP430 系列单片机实用 C 语言程序设计,北京:人民邮电出版社,2005
【31】 秦龙,MSP430 单片机常用模块与综合系统实例精讲,北京:电子工业出版社,2007
【32】 SAMSUM ELCTRONICS , K9F2808U0C datasheet ,http://www.samsung.com,2005
【33】 Future Technology Devices Intl. Ltd.,FT245BM USB FIFO ( USB - Parallel ) I.C.,http://www.ftdichip.com,2005
【34】 Future Technology Devices Intl. Ltd.,D2XX Programmer's Guide,http://www.ftdichip.com,2006
【35】 MAXIM datasheet,DS1302 Trickle-Charge Timekeeping Chip,Http://www.maxim.com,2005
【36】 高光天,传感器与信号调理器件应用技术,北京:科学出版社,2002
【37】 施因果德编著 徐德炳译,传感器的接口与信号调理电路,北京:国防工业出版社,1984
【38】 MAXIM datasheet, MAX761 12V High-Efficiency,Low IQ, Step-Up DC-DC Converters,Http://www.maxim.com,2005
【39】 MAXIM datasheet,MAX765 -12V High-Efficiency, Low IQ DC-DC Inverters,Http://www.maxim.com,2005
【40】 谭浩强,C 程序设计,北京:清华大学出版社,1991
【41】 Jean J.Labrosse,嵌入式实时操作系统 μC/OSⅡ(第二版),北京:北京航空航天大学出版社,2003
【42】 任哲 潘树林 房红征,嵌入式操作系统基础 μC/OSⅡ和 Linux,北京:北京航空航天大学出版社,2006
【43】 郑莉 董渊 张瑞丰,C++语言程序设计(第三版),北京:清华大学出版社,2003
【44】 郑阿奇,Visual C++教程,北京:清华大学出版社,2005
【45】 侯俊杰,深入浅出 MFC(第 2 版),武汉:华中科技大学出版社,2001
【46】 李志宏 余忠民,怎样正确理解和运用标准偏差 δ,机械开发,2000(2)
【47】 叶昌建,标准偏差 δ 的意义及在生产中的应用,计量技术,1995(8)