JPH06294690A - Temperature/nonlinearity compensation for magnetostrictive sensor - Google Patents
Temperature/nonlinearity compensation for magnetostrictive sensorInfo
- Publication number
- JPH06294690A JPH06294690A JP10754893A JP10754893A JPH06294690A JP H06294690 A JPH06294690 A JP H06294690A JP 10754893 A JP10754893 A JP 10754893A JP 10754893 A JP10754893 A JP 10754893A JP H06294690 A JPH06294690 A JP H06294690A
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- JP
- Japan
- Prior art keywords
- temperature
- voltage
- sensor
- output
- strain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
- Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、磁歪式センサの温度補
償及びその非直線性補償を行う信号処理の方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing method for temperature compensation of a magnetostrictive sensor and its nonlinear compensation.
【０００２】[0002]
【従来の技術】初めにこの種の歪センサの歪検出部の構
成を一部を切り欠いて図５に示す。201 は外力が加わる
センサシャフト、202 はセンサシャフト201 の外周面に
貼付された薄い膜状の磁性体で外力がセンサシャフト20
1 に加わるとこの薄い膜にも外力が及びこの外力により
生じる歪みに応じて透磁率が変化する磁歪膜、203,204
はセンサシャフト201 の一部の外周面に空隙を介して覆
被するようにして巻回されコイルを形成しこのコイルに
流される励磁電流により計測用の電磁界を発生させる励
磁コイル、205,206 は励磁コイル203,204 で発生した電
磁界磁束の外力から受ける歪みに比例して変化する磁歪
膜202 の透磁率の変化に比例して生起する信号電圧を検
出する検出コイル、207 は磁歪膜202 のある膜あり側
で、208は磁歪膜202 のない膜なし側である。なお、図
面において同一符号は同一もしくは相当部分を表す。2. Description of the Related Art First, a structure of a strain detecting portion of a strain sensor of this type is shown in FIG. 201 is a sensor shaft to which an external force is applied. 202 is a thin film magnetic material attached to the outer peripheral surface of the sensor shaft 201.
An external force is applied to this thin film when added to 1, and the magnetic permeability changes according to the strain caused by this external force.
Is an exciting coil which is wound so as to cover a part of the outer peripheral surface of the sensor shaft 201 with a gap therebetween to form a coil, and an exciting current flowing in this coil generates an electromagnetic field for measurement. 205 and 206 are exciting coils. A detection coil that detects the signal voltage that occurs in proportion to the change in the magnetic permeability of the magnetostrictive film 202 that changes in proportion to the strain received from the external force of the electromagnetic field magnetic flux generated in the coils 203 and 204. 207 is a film with the magnetostrictive film 202 On the side, 208 is a filmless side without the magnetostrictive film 202. In the drawings, the same reference numerals represent the same or corresponding parts.
【０００３】図６は、従来例１としての歪センサが具備
する信号処理回路の回路構成を表すブロック図である。
101 は一定周波数の交流電圧を発生する発振器、102 は
発振器101 からの電圧信号を電力増幅し先の励磁コイル
203,204 へ励磁電流を供給するパワーアンプであり、こ
れら発振器101 ，パワーアンプ102 ，励磁コイル203,20
4 で励磁回路が構成される。103,104 は検出コイル205,
206 によって検出された電圧信号のS/N を向上して電圧
増幅する初段アンプ(Pri-Amplifer)、105,106は交流電
圧を直流電圧へ変換する全波整流回路、107 は全波整流
回路105,106 からの検出直流電圧信号の偏差電圧を増幅
する差動増幅回路、109 は差動増幅回路107 の出力検出
電圧に含まれる高周波雑音を除去するローパスフィルタ
であり、これらの検出コイル205,206 、初段アンプ103,
104 ないしローパスフィルタ109にて検出回路が構成さ
れる。FIG. 6 is a block diagram showing a circuit configuration of a signal processing circuit included in the strain sensor as the first conventional example.
101 is an oscillator that generates an AC voltage of a constant frequency, 102 is the excitation coil of the destination that power-amplifies the voltage signal from the oscillator 101.
A power amplifier for supplying an exciting current to 203, 204. These oscillator 101, power amplifier 102, exciting coil 203, 20
The excitation circuit is composed of 4. 103 and 104 are detection coils 205,
A first-stage amplifier (Pri-Amplifer) that improves the S / N of the voltage signal detected by 206 to amplify the voltage, 105 and 106 are full-wave rectifier circuits that convert AC voltage to DC voltage, and 107 is a full-wave rectifier circuit from 105 and 106 A differential amplifier circuit that amplifies the deviation voltage of the detected DC voltage signal, and 109 is a low-pass filter that removes high frequency noise included in the output detection voltage of the differential amplifier circuit 107.These detection coils 205 and 206, the first stage amplifier 103,
A detection circuit is constituted by 104 or the low-pass filter 109.
【０００４】この従来例１は、外力が印加したセンサシ
ャフト201 に貼付された磁歪膜202の歪が変化すると、
その磁歪膜202 の透磁率が変化し、励磁コイル203 を流
れる励磁電流変化に基づく電磁界の磁束変化は検出コイ
ル205 の電圧変化となって検出される。これに引換え外
力がセンサシャフト201 に印加されても、図５から明ら
かなように、検出コイル206 の内周面が空隙を介し対抗
するセンサシャフト201 の外周面には磁歪膜202 が存在
しないから、検出コイル206 側の透磁率が変化せず、し
たがって励磁コイル204 を流れる励磁電流に基づく電磁
界の磁束変化はほとんどなく、検出コイル206 側で誘起
される電圧はほとんど変化しない。これらの検出コイル
205,206 で検出された電圧信号は、それぞれ初段アンプ
103,104 を通され、全波整流回路105,106 によって直流
電圧信号となった後に、差動増幅回路107 で差動増幅さ
れてから、ローパスフィルタ109 を経て歪信号110aとし
て取り出される。In this conventional example 1, when the strain of the magnetostrictive film 202 attached to the sensor shaft 201 to which an external force is applied changes,
The magnetic permeability of the magnetostrictive film 202 changes, and the change in the magnetic flux of the electromagnetic field based on the change in the exciting current flowing through the exciting coil 203 is detected as the voltage change in the detection coil 205. Even if an exchange external force is applied to the sensor shaft 201, as is apparent from FIG. 5, the magnetostrictive film 202 does not exist on the outer peripheral surface of the sensor shaft 201 which the inner peripheral surface of the detection coil 206 opposes through the gap. The magnetic permeability on the detection coil 206 side does not change, and therefore, the magnetic flux of the electromagnetic field based on the excitation current flowing through the excitation coil 204 hardly changes, and the voltage induced on the detection coil 206 side hardly changes. These detection coils
The voltage signals detected by 205 and 206 are respectively the first stage amplifier.
After passing through 103, 104 and converted into a DC voltage signal by the full-wave rectification circuits 105, 106, the signal is differentially amplified by the differential amplifier circuit 107 and then taken out as a distorted signal 110a through the low pass filter 109.
【０００５】さらに、従来例２として特開平４−２８６
９２７号トルク測定装置の感度補償装置がある。この従
来例２は、トルク伝達軸の外周面に磁気異方性部を形成
し、この磁気異方性部に対応して励磁コイルと検出コイ
ルとを設け、前記トルク伝達軸に印加されるトルクの大
小に応じた信号を前記検出コイルから出力して前記トル
クの大きさを測定するようにした磁歪式のトルクセンサ
において、前記励磁コイルに交流電流を供給する手段
と、前記励磁電流に直流成分をバイアスさせる手段と、
センサ部の温度を検出する手段と、温度検出信号にもと
づいて直流バイアス電流を制御する手段と、を有するこ
とを特徴とするトルク測定装置の感度補償装置である。Further, as a second conventional example, Japanese Patent Laid-Open No. 4-286.
There is a sensitivity compensator for the No. 927 torque measuring device. In this prior art example 2, a magnetic anisotropy portion is formed on the outer peripheral surface of the torque transmission shaft, an exciting coil and a detection coil are provided corresponding to the magnetic anisotropy portion, and the torque applied to the torque transmission shaft is set. In the magnetostrictive torque sensor, which outputs a signal according to the magnitude of the detection coil to measure the magnitude of the torque, means for supplying an alternating current to the exciting coil, and a direct current component in the exciting current. Means to bias
A sensitivity compensating device for a torque measuring device, comprising: a means for detecting the temperature of the sensor portion; and a means for controlling a DC bias current based on the temperature detection signal.
【０００６】[0006]
【発明が解決しようとする課題】ところが、従来例１に
おいては温度変化が生じた場合に、先の磁歪膜202 があ
る側とない側とでの温度ドリフトが異なるために差動を
とっても歪出力にドリフトを生じるといった問題点があ
った。また、歪−出力特性に非線形性があった。さら
に、従来例２ではセンサの温度の変化に対応して励磁電
流に直流成分をバイアスさせる手段を設けているが、こ
れはセンサが低温下や特に高温下での感度の補償をする
と記されてはいるけれども、その補償特性は直線性的な
ラフなものであり、しかもセンサ検出回路の非直線性の
補償は全く考慮さてはおらず、センサ検出精度としては
不十分な手段と言わざるを得ない。ここにおいて、本発
明は、これら従来例の全ての欠点を払拭した磁歪式セン
サの検出出力における温度ドリフトをなくすとともに、
非線形性の改善を図った磁歪センサの温度・非直線性補
償方法を提供することを目的とする。However, in the prior art example 1, when a temperature change occurs, since the temperature drift on the side where the magnetostrictive film 202 is present is different from that on the side where the magnetostrictive film 202 is not present, the strain output is obtained even if the differential is taken. There was a problem that it caused drift. In addition, the distortion-output characteristic had non-linearity. Further, in the second conventional example, a means for biasing the direct current component in the exciting current in response to the change in the temperature of the sensor is provided, but it is described that the sensor compensates the sensitivity at low temperature or particularly at high temperature. However, the compensation characteristics are linear and rough, and the compensation of the non-linearity of the sensor detection circuit is not taken into consideration at all, and it must be said that the sensor detection accuracy is insufficient. . Here, the present invention eliminates the temperature drift in the detection output of the magnetostrictive sensor that wipes out all the drawbacks of these conventional examples,
It is an object of the present invention to provide a method of compensating for temperature / non-linearity of a magnetostrictive sensor with an aim of improving non-linearity.
【０００７】[0007]
【課題を解決するための手段】上記問題を解決するため
に、本発明は、センサシャフトと、センサシャフト上に
形成された磁歪膜と１対の励磁コイルと１対の検出コイ
ルと出力段に差動増幅器を備える歪センサの信号処理回
路において、励磁コイル電圧を検出する励磁電圧検出回
路を介して歪センサの温度変化に伴う電圧変化を検出す
るとともに、各励磁コイル電圧である歪センサの温度に
応じた歪出力特性曲線と、理想的な歪・出力の特性を持
つ理想特性直線との、歪センサに印加されるそれぞれの
歪の大きさ毎の差分を補正値として、予め格納したテー
ブルＲＯＭを備えておき、前記励磁コイル電圧を全波整
流した温度に対応する電圧と歪出力を全波整流した歪電
圧をそれぞれマルチプレックサに導入し、前記マルチプ
レックサではＣＰＵからの指示によりそのいずれか一方
の電圧を選択し、Ａ／Ｄ変換してＲＡＭに記憶し、次に
他の電圧を選択し、Ａ／Ｄ変換して前記ＲＡＭに記憶
し、これら両電圧から前記テーブルＲＯＭの指定アドレ
スからの補正値を抽出し、抽出された補正値をＤ／Ａ変
換して、前記差動増幅器出力に加算する磁歪センサの温
度・非直線性補償方法である。In order to solve the above problems, the present invention provides a sensor shaft, a magnetostrictive film formed on the sensor shaft, a pair of exciting coils, a pair of detecting coils and an output stage. In the signal processing circuit of the strain sensor including the differential amplifier, the voltage change accompanying the temperature change of the strain sensor is detected through the excitation voltage detection circuit that detects the excitation coil voltage, and the temperature of the strain sensor that is each excitation coil voltage is detected. Table ROM pre-stored as the correction value, the difference between the distortion output characteristic curve corresponding to the above and the ideal characteristic straight line having the ideal distortion / output characteristic for each distortion magnitude applied to the distortion sensor And a voltage corresponding to the temperature obtained by full-wave rectifying the exciting coil voltage and a distortion voltage obtained by full-wave rectifying the distortion output are respectively introduced into the multiplexer, and in the multiplexer, the CP is applied. In accordance with the instruction from, one of the voltages is selected, A / D converted and stored in the RAM, then another voltage is selected, A / D converted and stored in the RAM, and both voltages are selected. It is a method of compensating temperature / non-linearity of a magnetostrictive sensor which extracts a correction value from a designated address of the table ROM, D / A converts the extracted correction value, and adds it to the output of the differential amplifier.
【０００８】[0008]
【作用】上記手段により、温度変化による励磁電圧変化
が生じても、その励磁電圧のときの温度・歪出力に適応
した補正値を差動増幅回路出力に加算するので、常に温
度ドリフトのない、また、非線形性のない歪−出力特性
を得ることができる。By the above means, even if the exciting voltage changes due to the temperature change, the correction value adapted to the temperature / distortion output at the exciting voltage is added to the differential amplifier circuit output, so that there is always no temperature drift. In addition, it is possible to obtain distortion-output characteristics without non-linearity.
【０００９】[0009]
【実施例】以下、本発明の実施例を図に基づいて説明す
る。図１は、本発明の一実施例における信号処理回路を
備えた磁歪式歪センサの回路構成を示すブロック図であ
る。111 は励磁電圧検出回路、112 はテーブルＲＯＭ、
113 はＤ／Ａコンバータ、108 は加算器である。ここ
で、励磁電圧検出回路111 はセンサシャフト201 を空隙
を介してその外周面を加熱する、すなわち交流電流を流
すことにより交番磁界を発生させ検出コイルにおける誘
起電圧を検出するのではあるが、同時にジュール損によ
る発熱があり、これが歪センサの環境温度を形成する。
しかし、この磁歪膜202 がある膜あり側207 と膜なし側
208 側では、温度係数が異なるため環境温度も多分に相
違することは論を待たない。従って、この現象が次段以
降での差動演算にもかかわらず、温度ドリフトないしは
非直線性をなす所以である。そこで、本発明は、この励
磁コイル203,204 から取り出した励磁電圧を温度を含む
情報として扱い、これを適当な係数器を経て演算に適し
た値に改めてから、全波整流して次のテーブルＲＯＭへ
温度情報として与えている。これらの情報処理の全てを
励磁電圧検出回路111 において行われる。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration of a magnetostrictive strain sensor including a signal processing circuit according to an embodiment of the present invention. 111 is an excitation voltage detection circuit, 112 is a table ROM,
Reference numeral 113 is a D / A converter, and 108 is an adder. Here, the excitation voltage detection circuit 111 heats the outer peripheral surface of the sensor shaft 201 via a gap, that is, generates an alternating magnetic field by passing an alternating current and detects the induced voltage in the detection coil. There is heat generation due to Joule loss, which forms the ambient temperature of the strain sensor.
However, the film side 207 with this magnetostrictive film 202 and the filmless side
On the 208 side, it is arguable that the environmental temperature is probably different because the temperature coefficient is different. Therefore, this phenomenon is the reason why the temperature drift or the non-linearity occurs despite the differential calculation in the subsequent stages. Therefore, according to the present invention, the exciting voltage extracted from the exciting coils 203 and 204 is treated as information including temperature, and is converted into a value suitable for calculation through an appropriate coefficient unit and then full-wave rectified to the next table ROM. It is given as temperature information. All of these information processes are performed in the excitation voltage detection circuit 111.
【００１０】次に、テーブルＲＯＭ112 の内部構成の詳
細について説明する。図２は、この一実施例で採用した
回路の主要部を示すブロック図で、デジタル演算のため
のクロック回路などは省略している。112aはマルチプレ
ックサ（Mul-tiplexer) で、第１の入力は前段の励磁電
圧検出回路111 からの歪センサ温度に相当する直流信号
電圧を導入し、第２の入力は歪センサの出力の全波整流
回路105 からの歪出力に相当する直流信号電圧を受入
れ、それら両信号電圧の中の一つを取捨選択して内部に
取り入れる。112bはＡ／Ｄコンバータでる。マルチプレ
ックサ112aからのアナログ信号を内部演算可能にするた
めにデジタル化する。Ａ／Ｄコンバータを経た信号はバ
ス112fを介してＣＰＵ（中央処理装置）の指示により、
ＲＡＭに一時記憶格納される。そして、ＣＰＵからのさ
らなる指示でマルチプレックサ112aは他の信号電圧を選
択して、先と同じようにしてその信号をＲＡＭに一時記
憶格納される。これら両信号からＣＰＵの判断がなさ
れ、予めテーブル状に補正値が格納されたＲＯＭのアド
レスが指定され、そのアドレスが持つ補正値がバス112f
を経て次段のＤ／Ａコンバータ113 へ送り出される。Next, details of the internal structure of the table ROM 112 will be described. FIG. 2 is a block diagram showing a main part of a circuit adopted in this embodiment, and a clock circuit for digital operation is omitted. 112a is a multiplexer (Mul-tiplexer), the first input of which introduces a DC signal voltage corresponding to the strain sensor temperature from the excitation voltage detection circuit 111 in the previous stage, and the second input of which is the entire output of the strain sensor. The DC signal voltage corresponding to the distorted output from the wave rectifier circuit 105 is received, and one of these two signal voltages is selected and taken into the inside. 112b is an A / D converter. The analog signal from the multiplexer 112a is digitized to enable internal calculation. The signal passed through the A / D converter is instructed by the CPU (central processing unit) via the bus 112f,
Temporarily stored in RAM. Then, according to a further instruction from the CPU, the multiplexer 112a selects another signal voltage, and the signal is temporarily stored in the RAM in the same manner as before. The CPU makes a determination based on both of these signals, and the address of the ROM in which the correction values are stored in advance in the form of a table is specified.
And is sent to the D / A converter 113 at the next stage.
【００１１】図３は、各補正値をテーブル状に格納した
ＲＯＭの形状を表す図である。この図は歪センサの各温
度・歪出力特性の適宜にサンプリングしたデータと誤差
のない理想特性との差分を、アドレスごとに格納した状
態図である。例えば、Ｔ2 ・温度特性での歪出力Ｓ2 の
ときの補正値はいくらという具合にして格納される。図
４は、そのテーブルＲＯＭに格納される補正値の算出手
段の説明図である。いま、室温にて最適励磁電流（励磁
電圧V ref) に設定したときの歪−出力特性が図４に示
す［温度・Ｔ4 ・曲線］の特性曲線である。すなわち、
この図４のように、最適励磁電流値に設定してもセンサ
ヘッド（センサシャフト201 ないし検出コイル206 など
の構成要素からなる歪み検出の先端部分）の歪−出力特
性からの非直線性が存在する。この歪−出力特性のデー
タから、例えば最小自乗法等で［理想直線］を引き、こ
の［理想直線］と、実際の室温で最適励磁電流に設定の
歪−出力特性の［温度・Ｔ4 ・曲線］で示す特性曲線と
のデータの差を補正値として、テーブルＲＯＭ112 ［そ
のアドレスは（Ｔ2 ）の行の（Ｓ2 ）の列に示した斜線
部分］に格納しておく。例えば歪がＳ1 ，Ｓ2 ，Ｓ3 ，
…，ＳM-2 ，ＳM-1 ，ＳM と変化すれば差分の補正値
は、60−40, 61−41, 62−42, 63−43, …，65−45, 66
−46, 67−47とのそれぞれの差の長さで表される。FIG. 3 is a diagram showing the shape of a ROM in which each correction value is stored in a table. This figure is a state diagram in which the difference between the properly sampled data of each temperature / strain output characteristic of the strain sensor and the ideal characteristic without error is stored for each address. For example, how much the correction value for the strain output S 2 in the T 2 / temperature characteristic is stored. FIG. 4 is an explanatory diagram of the correction value calculation means stored in the table ROM. Is a characteristic curve of the output characteristics shown in FIG. 4 Temperature · T 4 · Curve - Now, distortion when set to the optimum excitation current (exciting voltage V ref) at room temperature. That is,
As shown in FIG. 4, even if the optimum excitation current value is set, there is non-linearity from the distortion-output characteristics of the sensor head (the tip of distortion detection consisting of the components such as the sensor shaft 201 or the detection coil 206). To do. From this distortion-output characteristic data, for example, the [ideal straight line] is drawn by the method of least squares, and this [ideal straight line] and the [temperature / T 4 ·. [Curve] is stored as a correction value in the table ROM 112 [the address is the shaded portion shown in the column (S 2 ) of the row (T 2 )]. For example, if the distortion is S 1 , S 2 , S 3 ,
…, S M-2 , S M-1 , S M , the difference correction values are 60-40, 61-41, 62-42, 63-43, ..., 65-45, 66.
It is expressed by the length of the difference between −46 and 67−47.
【００１２】ここで、歪センサを取り巻く温度が変化す
ると、この歪センサの歪−出力特性の［温度・Ｔ2 ・曲
線］にドリフトを生じる。このドリフトの要因の大きな
１つに温度変化による励磁電圧の変化がある。この励磁
電圧の変化は励磁回路を構成している発振器101 、パワ
ーアンプ102 の温度ドリフト、また励磁コイル203,204
の温度特性などに起因する。さらに励磁電流が最適励磁
電流値からずれれば、歪−出力特性自体も変化し、ドリ
フトの要因となる。本来であれば励磁電圧が変化して
も、信号処理回路で差動構成を取っているため、この温
度ドリフトはキャンセルされるはずであるが、実際には
磁歪膜202 がある側207 とない側208 とで励磁コイル20
3 と励磁コイル204 で、同じだけ励磁電圧が変化した場
合に、検出コイル205 側と検出コイル206 側とでは各相
での温度特性の違いからドリフト量が異なる。このた
め、ドリフトをキャンセルすることができない。上記の
ような理由により、温度変化が生じると、励磁電圧が変
化し、歪センサの歪−出力特性に図４の励磁電圧Ｖ1 の
［温度・Ｔ2 ・曲線］の特性曲線あるいは励磁電圧Ｖ2
の［温度・ＴN-1 ・曲線］の特性曲線などのようなドリ
フト、つまり零点ドリフト及び感度ドリフトが生じる。[0012] Here, when the temperature changes around the strain sensor, the strain of the strain sensor - caused drift in the temperature · T 2 · curve on the output characteristics. One of the major causes of this drift is the change of the excitation voltage due to the temperature change. This change in the excitation voltage is caused by the temperature drift of the oscillator 101 and the power amplifier 102 that form the excitation circuit, and the excitation coils 203 and 204.
Due to the temperature characteristics of. Further, if the exciting current deviates from the optimum exciting current value, the distortion-output characteristic itself also changes, which causes a drift. Normally, even if the excitation voltage changes, this temperature drift should be canceled because the signal processing circuit uses a differential configuration, but in reality, the side with 207 the magnetostrictive film 202 and the side without 207 Excitation coil 20 with 208
3 and the exciting coil 204, when the exciting voltage changes by the same amount, the drift amount differs between the detection coil 205 side and the detection coil 206 side due to the difference in temperature characteristics in each phase. Therefore, the drift cannot be canceled. Due to the above reason, when the temperature changes, the exciting voltage changes, and the distortion-output characteristic of the strain sensor shows the characteristic curve of [temperature / T 2 · curve] of the exciting voltage V 1 of FIG. 4 or the exciting voltage V. 2
[Temperature / TN-1 / curve] characteristic curve, that is, zero drift and sensitivity drift occur.
【００１３】そこで、本発明は予め励磁電圧を振って、
実際の室温で最適励磁電流（励磁電圧V ref) に設定の
歪−出力特性の［温度・Ｔ4 ・曲線］の特性曲線を取
り、励磁電圧毎に先に述べた［理想直線］との差を補正
値として先のテーブルＲＯＭ112 に格納しておく。因
に、励磁電圧Ｖ1 の［温度・Ｔ2 ・曲線］の特性曲線の
ときにおける補正値は、歪がＳ1 ，Ｓ2 ，Ｓ3 ，…，Ｓ
M-2 ，ＳM-1 ，ＳM と変化すれば差分の補正値は、50−
40, 51−41, 52−42, 53−43, …，55−45, 56−46, 57
−47とのそれぞれの差の長さで表され、励磁電圧Ｖ2 の
［温度・ＴN-1 ・曲線］の特性曲線の場合もこれらに準
じる。信号処理においては、励磁電圧を励磁電圧検出回
路111 により検出してこれを全波整流し、この直流電圧
（温度）とそのときの歪み（全波整流回路105 からの歪
出力）に応じた補正値をテーブルＲＯＭ112 により払い
出して、加算器108 において差動増幅器107 の出力に加
算することにより、温度変化による励磁電圧の変化があ
っても、常に［理想直線］の通りに歪センサの歪−出力
特性110 が得られる。そして、本発明はトルクセンサ、
圧力センサ、張力センサなど各種の歪センサにそれぞれ
適用可能である。Therefore, according to the present invention, the exciting voltage is applied in advance,
The actual strain at room temperature setting to the optimum excitation current (exciting voltage V ref) - the difference between the take characteristic curve of the temperature · T 4 · Curve was described previously for each excitation voltage [ideal straight line on the output characteristics Is stored in the previous table ROM 112 as a correction value. Incidentally, in the correction value of the exciting voltage V 1 in the case of the characteristic curve of [Temperature / T 2 · curve], the distortion is S 1 , S 2 , S 3 , ..., S.
If it changes to M-2 , S M-1 , and S M , the difference correction value becomes 50-
40, 51−41, 52−42, 53−43,…, 55−45, 56−46, 57
It is represented by the length of each difference from −47, and the same applies to the case of the characteristic curve of [temperature / TN-1 / curve] of the excitation voltage V 2 . In signal processing, the excitation voltage is detected by the excitation voltage detection circuit 111, full-wave rectified, and corrected according to this DC voltage (temperature) and the distortion at that time (distortion output from the full-wave rectification circuit 105). The value is output from the table ROM 112 and added to the output of the differential amplifier 107 in the adder 108, so that even if there is a change in the excitation voltage due to a temperature change, the strain-output of the strain sensor always follows the [ideal straight line]. The characteristic 110 is obtained. And the present invention provides a torque sensor,
It can be applied to various strain sensors such as a pressure sensor and a tension sensor.
【００１４】[0014]
【発明の効果】以上述べたように、本発明によれば温度
変化による励磁電圧の変化が生じても、零点ドリフト及
び感度ドリフトなどのドリフトを生じず、また常に直線
性のよい歪センサの歪−出力特性を得ることができる。As described above, according to the present invention, even if the exciting voltage changes due to temperature change, drifts such as zero-point drift and sensitivity drift do not occur, and the strain of the strain sensor with good linearity is always maintained. -The output characteristics can be obtained.
【図１】本発明の一実施例における回路構成を示すブロ
ック図FIG. 1 is a block diagram showing a circuit configuration according to an embodiment of the present invention.
【図２】本発明の一実施例でのテーブルＲＯＭの内部の
回路構成を表すブロック図FIG. 2 is a block diagram showing the internal circuit configuration of a table ROM in one embodiment of the present invention.
【図３】本発明の一実施例におけるＲＯＭのアドレステ
ーブルの説明図FIG. 3 is an explanatory diagram of a ROM address table according to an embodiment of the present invention.
【図４】本発明の一実施例での歪センサの歪−出力特性
を表す図FIG. 4 is a diagram showing a strain-output characteristic of a strain sensor according to an embodiment of the present invention.
【図５】歪センサのセンサヘッドの構成を表す一部を切
り欠いた側面図FIG. 5 is a side view showing a configuration of a sensor head of a strain sensor with a part cut away.
【図６】従来例１における歪センサとその信号処理回路
の回路構成を示すブロック図FIG. 6 is a block diagram showing a circuit configuration of a strain sensor and its signal processing circuit in Conventional Example 1.
101 発振器 102 パワーアンプ 103 初段アンプ 104 初段アンプ 105 全波整流回路 106 全波整流回路 107 差動増幅器 108 加算器 109 ローパスフィルタ 110 歪出力［本発明］ 110a 歪出力［従来例１］ 111 励磁電圧検出回路 112 テーブルＲＯＭ 112a マルチプレックサ 112b Ａ／Ｄコンバータ 112c ＣＰＵ 112d ＲＡＭ 112e ＲＯＭ 113 Ｄ／Ａコンバータ 101 Oscillator 102 Power amplifier 103 First stage amplifier 104 First stage amplifier 105 Full wave rectification circuit 106 Full wave rectification circuit 107 Differential amplifier 108 Adder 109 Low pass filter 110 Distortion output [present invention] 110a Distortion output [Conventional example 1] 111 Excitation voltage detection Circuit 112 Table ROM 112a Multiplexer 112b A / D converter 112c CPU 112d RAM 112e ROM 113 D / A converter
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成５年１０月２７日[Submission date] October 27, 1993
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】図面[Document name to be corrected] Drawing
【補正対象項目名】全図[Correction target item name] All drawings
【補正方法】追加[Correction method] Added
【補正内容】[Correction content]
【図２】 [Fig. 2]
【図１】 [Figure 1]
【図３】 [Figure 3]
【図４】 [Figure 4]
【図５】 [Figure 5]
【図６】 [Figure 6]
───────────────────────────────────────────────────── フロントページの続き (72)発明者 上村 浩司 福岡県北九州市八幡西区黒崎城石２番１号 株式会社安川電機内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koji Uemura Inventor Koji Kurosaki No. 2-1, Kurosaki Shiroishi, Hachimannishi-ku, Kitakyushu, Fukuoka
Claims (1)
成された磁歪膜と１対の励磁コイルと１対の検出コイル
と出力段に差動増幅器を備える歪センサの信号処理回路
において、 励磁コイル電圧を検出する励磁電圧検出回路を介して歪
センサの温度変化に伴う電圧変化を検出するとともに、 各励磁コイル電圧である歪センサの温度に応じた歪出力
特性曲線と、理想的な歪・出力の特性を持つ理想特性直
線との、歪センサに印加されるそれぞれの歪の大きさ毎
の差分を補正値として、予め格納したテーブルＲＯＭを
備えておき、 前記励磁コイル電圧を全波整流した温度に対応する電圧
と歪出力を全波整流した歪電圧をそれぞれマルチプレッ
クサに導入し、 前記マルチプレックサではＣＰＵからの指示によりその
いずれか一方の電圧を選択し、Ａ／Ｄ変換してＲＡＭに
記憶し、 次に他の電圧を選択し、Ａ／Ｄ変換して前記ＲＡＭに記
憶し、 これら両電圧から前記テーブルＲＯＭのアドレスを指定
し、 前記テーブルＲＯＭの指定アドレスからの補正値を抽出
し、 抽出された補正値をＤ／Ａ変換して、前記差動増幅器出
力に加算することを特徴とする磁歪センサの温度・非直
線性補償方法。1. A signal processing circuit of a strain sensor, comprising: a sensor shaft; a magnetostrictive film formed on the sensor shaft; a pair of exciting coils; a pair of detecting coils; and a differential amplifier in an output stage. The voltage change due to the temperature change of the strain sensor is detected via the excitation voltage detection circuit that detects the strain output characteristic curve according to the temperature of the strain sensor that is each excitation coil voltage, and the ideal strain / output A table ROM that stores in advance the difference between the ideal characteristic line having the characteristics and the magnitude of each strain applied to the strain sensor as a correction value is provided, and the excitation coil voltage is subjected to full-wave rectification at the temperature. The corresponding voltage and the distorted voltage obtained by full-wave rectifying the distorted output are respectively introduced into the multiplexer, and in the multiplexer, one of the voltages is selected according to the instruction from the CPU, A / D converted and stored in RAM, then another voltage is selected, A / D converted and stored in RAM, the address of the table ROM is specified from these both voltages, and the table ROM is specified A method for compensating temperature / non-linearity of a magnetostrictive sensor, characterized in that a correction value from an address is extracted, the extracted correction value is D / A converted and added to the output of the differential amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10754893A JPH06294690A (en) | 1993-04-09 | 1993-04-09 | Temperature/nonlinearity compensation for magnetostrictive sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10754893A JPH06294690A (en) | 1993-04-09 | 1993-04-09 | Temperature/nonlinearity compensation for magnetostrictive sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06294690A true JPH06294690A (en) | 1994-10-21 |
Family
ID=14461980
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10754893A Pending JPH06294690A (en) | 1993-04-09 | 1993-04-09 | Temperature/nonlinearity compensation for magnetostrictive sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06294690A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09245214A (en) * | 1996-03-08 | 1997-09-19 | Glory Ltd | Coin discrimination device having temperature compensation function for coin processing machine |
| JP2000121462A (en) * | 1998-10-15 | 2000-04-28 | Koyo Seiko Co Ltd | Torque sensor and steering apparatus |
| US6600311B1 (en) | 1999-05-26 | 2003-07-29 | Matsushita Electric Works, Ltd. | Magnetic sensor for detecting the angular displacement of a rotating shaft |
| US10466313B2 (en) | 2014-12-12 | 2019-11-05 | Korea Research Institute Of Standards And Science | Magnetic field sensor and apparatus for measuring magnetic field |
-
1993
- 1993-04-09 JP JP10754893A patent/JPH06294690A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09245214A (en) * | 1996-03-08 | 1997-09-19 | Glory Ltd | Coin discrimination device having temperature compensation function for coin processing machine |
| JP2000121462A (en) * | 1998-10-15 | 2000-04-28 | Koyo Seiko Co Ltd | Torque sensor and steering apparatus |
| US6600311B1 (en) | 1999-05-26 | 2003-07-29 | Matsushita Electric Works, Ltd. | Magnetic sensor for detecting the angular displacement of a rotating shaft |
| US10466313B2 (en) | 2014-12-12 | 2019-11-05 | Korea Research Institute Of Standards And Science | Magnetic field sensor and apparatus for measuring magnetic field |
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