JPH03150401A - Magnetic detector - Google Patents
Magnetic detectorInfo
- Publication number
- JPH03150401A JPH03150401A JP2013052A JP1305290A JPH03150401A JP H03150401 A JPH03150401 A JP H03150401A JP 2013052 A JP2013052 A JP 2013052A JP 1305290 A JP1305290 A JP 1305290A JP H03150401 A JPH03150401 A JP H03150401A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- circuit
- circuits
- differential
- coil
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 claims abstract description 28
- 230000005284 excitation Effects 0.000 claims description 20
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 5
- 230000003321 amplification Effects 0.000 claims description 4
- 230000010355 oscillation Effects 0.000 claims description 2
- 238000013459 approach Methods 0.000 description 6
- 239000004020 conductor Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Geophysics And Detection Of Objects (AREA)
- Control Of Position, Course, Altitude, Or Attitude Of Moving Bodies (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は磁気検知器に関し、特に磁性体又は導電体をガ
イドレーンとして走行する無人搬送車などのガイドレー
ン位置検出用として好適な磁気検知器に関するものであ
る。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic detector, and particularly to a magnetic detector suitable for detecting the position of a guide lane of an automatic guided vehicle or the like that runs on a magnetic or conductive material as a guide lane. It is related to.
磁性体の存在を検知する磁気検知器の１つに、交流磁場
を発生する励起コイルとそれが作る磁場によって誘導電
圧を生ずる検知コイルから成る自己励磁型のものがある
。これは、構造が簡単で設計の自由度も大きいことから
、従来種々の車両誘導システム等に利用され役立ってい
る。これらの誘導システムでは、帯状の磁性体又は金属
等の導電体をガイドレーンとして誘導すべき道に設けて
−誘導されるべきもの（車両等）に取り付けられた検知
器の信号からガイドレーンの方向を知り、それに応じて
操舵し、目的の場所に誘導するものである。One type of magnetic detector that detects the presence of a magnetic substance is a self-excitation type that includes an excitation coil that generates an alternating magnetic field and a detection coil that generates an induced voltage by the generated magnetic field. This has a simple structure and a large degree of freedom in design, so it has been used and useful in various vehicle guidance systems. In these guidance systems, a conductive material such as a magnetic or metal strip is installed as a guide lane on the road to be guided, and the direction of the guide lane is determined from the signal of a detector attached to the object to be guided (vehicle, etc.). The robot learns the location, steers the vehicle accordingly, and guides the vehicle to the desired location.
従来の磁気検知器としては−第２図に示すようなコイル
配置で第３図に示すような回路構成を有するものが知ら
れている。この磁気検知器では、励起コイル２に発振器
１を接続して交流電流を流す、すると、励起コイル２か
ら励起磁界９が発生する。この励起磁界９の一部が検知
コイル３゜３′を貫くことにより、検知コイル３．３′
に誘導電圧が生ずる。この誘導電圧はそれぞれ増幅回路
８，８′を経て整流回路６．６′で整流された後、差動
回路７に入力され、検知コイル３．３′による２つの信
号の差が出力される。As a conventional magnetic detector, one having a coil arrangement as shown in FIG. 2 and a circuit configuration as shown in FIG. 3 is known. In this magnetic detector, when an oscillator 1 is connected to an excitation coil 2 and an alternating current is caused to flow, an excitation magnetic field 9 is generated from the excitation coil 2. A part of this excitation magnetic field 9 penetrates the detection coil 3.3', causing the detection coil 3.3'
An induced voltage is generated. These induced voltages pass through amplifier circuits 8 and 8', are rectified by rectifier circuits 6 and 6', and then are input to a differential circuit 7, where the difference between the two signals from the detection coil 3 and 3' is output.
このような構成−ａｒｔの磁気検知器において、検知コ
イル３に空気より大きな比透磁率をもつ磁性体が接近す
ると、磁界分布が変化し、検知コイルを貫く磁束も変化
する。また、導電体が接近すると、導電体に生ずる渦電
流により磁界が変化する。その結果、検知コイルに誘導
される電圧も変化することになる。磁性体又は導電体が
２つの検知コイルから対称な位置（第２図の中心軸り上
）にある場合は磁界分布は対称となり、２つの検知コイ
ルの誘導電圧も等しいため、検知器出力も零となる。し
かし、磁性体又は導電体で作られたガイドレーンが片側
の検知コイルにより接近すると、左右の検知コイル電圧
が不平衡となり、差動回路７の出力電圧が不平衡の程度
に応じて正又は負となる。従って、この電圧を制御信号
として用いることにより、誘導されるべき物（車両等）
をガイドレーンに沿って走行させることができる。In the magnetic detector having such a configuration -art, when a magnetic body having a relative magnetic permeability greater than that of air approaches the detection coil 3, the magnetic field distribution changes and the magnetic flux passing through the detection coil also changes. Furthermore, when a conductor approaches, the magnetic field changes due to eddy currents generated in the conductor. As a result, the voltage induced in the sensing coil will also change. If the magnetic material or conductive material is located at a symmetrical position from the two sensing coils (on the center axis in Figure 2), the magnetic field distribution will be symmetrical, and the induced voltages of the two sensing coils will be equal, so the detector output will also be zero. becomes. However, when a guide lane made of a magnetic or conductive material approaches one of the sensing coils, the voltages of the left and right sensing coils become unbalanced, and the output voltage of the differential circuit 7 becomes positive or negative depending on the degree of unbalance. becomes. Therefore, by using this voltage as a control signal, the object to be guided (vehicle, etc.)
can be run along guide lanes.
上述した従来の磁気検知器では、励起コイル２と検知コ
イル３．３′とが近接しているので、被検知物が近接し
ない場合にも検知コイルに生ずる電圧は小さくない。こ
の場合、被検知物が近接したことによる検知コイルに生
ずる電圧の変化は非−常にわずかであり、回路の温度特
性等で電圧変化を検知することが難しい。これを解決す
るには、被検知物が近接しない時に、検知コイルに生ず
る電圧を小さくする必要がある。そのためには、第４図
に示す点Ａのように検知コイルに鎖交する磁界がバラン
スした点の近くに検知コイルを固定する必要がある。し
かしこのバランス点の近傍では少しの取付誤差でも磁界
の変化が大きいため、検知コイルの位置設定が難しく多
大な工数を要し、更に使用中の振動や温度変化による位
置ずれを防ぐための構造が複雑化、大型化するという欠
点がある。In the conventional magnetic detector described above, since the excitation coil 2 and the detection coil 3.3' are close to each other, the voltage generated in the detection coil is not small even when the object to be detected is not close to each other. In this case, the change in voltage that occurs in the detection coil due to the proximity of the object to be detected is very small, and it is difficult to detect the voltage change due to the temperature characteristics of the circuit. To solve this problem, it is necessary to reduce the voltage generated in the detection coil when the object to be detected is not in close proximity. For this purpose, it is necessary to fix the sensing coil near a point where the magnetic fields interlinking with the sensing coil are balanced, such as point A shown in FIG. However, in the vicinity of this balance point, even a small installation error causes a large change in the magnetic field, making it difficult to set the position of the detection coil and requiring a large amount of man-hours.Furthermore, a structure is required to prevent misalignment due to vibration or temperature changes during use. It has the disadvantage of becoming more complex and larger.
本発明の磁気検知器は、発振回路から与えられる交流電
流により交流磁界を発生する励起コイルと、おのおの前
記交流磁界に鎖交して誘導電圧を生じる第１および第２
の検知コイルと−前記励起コイルの両端電圧と各前記誘
導電圧との差電圧をそれぞれ発生する第１および第２の
差動回路と、各前記差電圧を整流する第１および第２の
整流回路と、該第１および第２の整流回路の整流電圧の
差電圧を出力する第３の差動回路とを備えている。The magnetic detector of the present invention includes an excitation coil that generates an alternating magnetic field using an alternating current applied from an oscillation circuit, and first and second coils that each interlink with the alternating magnetic field and generate an induced voltage.
a detection coil; - first and second differential circuits that generate a voltage difference between the voltage across the excitation coil and each of the induced voltages, and first and second rectifier circuits that rectify each of the voltage differences; and a third differential circuit that outputs a differential voltage between rectified voltages of the first and second rectifier circuits.
次に本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図は本発明の第１の実施例の回路図である。検知コ
イル３．３′の信号は増幅回路８゜８′で増幅される。FIG. 1 is a circuit diagram of a first embodiment of the present invention. The signal from the detection coil 3.3' is amplified by an amplifier circuit 8.8'.
一方、励起コイル２の両端電圧は位相反転回路４を経て
、信号の和回路５゜５′に入力されている。検知コイル
信号と励起コイル信号とは、和回路５．５′により各々
定数倍されて加算されるが、その比率は可変抵抗器５ａ
、５ａ″によって可変できる構成となっている。和回路
５，５′の出力信号は整流回路６゜６′で整流されて差
動回路７へ入力されている。On the other hand, the voltage across the excitation coil 2 is inputted to a signal summation circuit 5.degree. 5' via a phase inversion circuit 4. The detection coil signal and the excitation coil signal are each multiplied by a constant and added by the summation circuit 5.5', and the ratio is determined by the variable resistor 5a.
, 5a''. The output signals of the summation circuits 5 and 5' are rectified by a rectifier circuit 6°6' and input to a differential circuit 7.
本実施例では、被検知物が近接にない状態で整流回路６
．６′の出力が０となるよう可変抵抗器５ａ、５ａ”を
初期調整しておく。使用時に被検知物が検知コイル３又
は３′に接近した場合は、被検知物が接近した検知コイ
ルと励起コイル２との磁気結合が変化するため、その整
流出力が変化する。したがって、２つの整流出力の差を
差動回路７を通して得ることにより被検知物と磁気検知
器との相対位置を知ることができる。In this embodiment, the rectifier circuit 6
．． The variable resistors 5a and 5a'' are initially adjusted so that the output of 6' becomes 0.When an object to be detected approaches the detection coil 3 or 3' during use, the Since the magnetic coupling with the excitation coil 2 changes, its rectified output changes. Therefore, by obtaining the difference between the two rectified outputs through the differential circuit 7, it is possible to know the relative position of the object to be detected and the magnetic detector. Can be done.
上述のごとく本実施例では、検知コイル３゜３′の位置
調整をせずに、可変抵抗器５ａ、５ａで初期調整できる
ので従来のような煩雑な検知コイル位置調整をせずに済
む。更に、励振コイル２と検知コイル３．３′との相対
位置を固定しても良いので、第５図に示すごとく各コイ
ルを同一の磁心１２に巻線でき、構造を簡単化、小形化
できる。As described above, in this embodiment, the initial adjustment can be made using the variable resistors 5a, 5a without adjusting the position of the detection coil 3.degree. 3', so that the complicated position adjustment of the detection coil as in the conventional case can be avoided. Furthermore, since the relative positions of the excitation coil 2 and the detection coil 3.3' may be fixed, each coil can be wound around the same magnetic core 12 as shown in Fig. 5, making the structure simpler and more compact. .
第６図は本発明の第２の実施例を示す回路図である。本
実施例では、第５図に示すように励振コイル２と検知コ
イル３．３′とを同一の磁心１２に巻線してある。励振
コイル２が発生する磁界の検知コイル３．３′への交さ
量は、被検知物の接近により変化し、これに応じて検知
コイル３゜３′の誘導電圧が変化する。両誘導電圧はそ
れぞれ、増幅回路８．８′で増幅された後、可変抵抗器
により増幅度を可変し得る可変増幅回路１５を通した励
振コイル２の両端電圧との差を、差動増幅回路１４．１
４で発生させる。この二つの差信号はそれぞれ、整流回
路６．６′で整流された後、差動回路７で両検知コイル
電圧の不平衡を示す出力信号を発生させる。FIG. 6 is a circuit diagram showing a second embodiment of the present invention. In this embodiment, the excitation coil 2 and the detection coil 3.3' are wound around the same magnetic core 12, as shown in FIG. The amount of magnetic field generated by the excitation coil 2 that crosses the detection coil 3.3' changes as the object to be detected approaches, and the induced voltage in the detection coil 3.3' changes accordingly. Both induced voltages are amplified by amplifier circuits 8 and 8', and then passed through a variable amplifier circuit 15 whose amplification degree can be varied by a variable resistor. 14.1
Generate in 4. These two difference signals are each rectified by a rectifier circuit 6, 6', and then a differential circuit 7 generates an output signal indicating the imbalance between the voltages of both sensing coils.
まず、被検知物に接近していない状態で差動増幅回路１
４．１４の各出力電圧がゼロになるよう可変増幅回路１
５．１５”の増幅度を調整しておく、このあと被検知物
が接近すると、検知コイル３．３′の誘導電圧の変化分
のみが差動増幅回路１４．１４”から出力される。この
両検知電圧の差を差動増幅回路７から出力して、これに
より磁界の変化が左右いずれで大きいかを判定でき、被
検知物が磁気検知器の左右いずれの側にあるかを判定で
きる。First, the differential amplifier circuit 1 is
4. Variable amplifier circuit 1 so that each output voltage in 14 becomes zero
After adjusting the amplification degree of 5.15'', when the object to be detected approaches, only the change in the induced voltage of the sensing coil 3.3' is output from the differential amplifier circuit 14.14''. The difference between these two detection voltages is output from the differential amplifier circuit 7, and it can be determined whether the change in the magnetic field is larger on the left or right side, and it can be determined whether the detected object is on the left or right side of the magnetic detector. .
本実施例でも、煩雑な検知コイル位置決めをせずに済み
、且つ構造の簡単化、小形化を図れる。In this embodiment as well, there is no need for complicated positioning of the detection coil, and the structure can be simplified and downsized.
以上説明したように本発明は、被検知物に接近させない
状態での初期調整を従来のような煩雑な検知コイル位置
設定によらず回路調節で行なうことができ−更に励振コ
イルおよび検知コイルを同一磁心に巻線した構造にでき
るので使用中のコイル位置ずれを生じること無く安定な
動作を得るという効果がある。As explained above, the present invention allows initial adjustment without bringing the object to be detected close to the object to be detected by adjusting the circuit without requiring complicated detection coil position settings as in the conventional method. Since the structure is such that the wires are wound around a magnetic core, stable operation can be achieved without causing the coil position to shift during use.
図面の簡単な説明
第１図および第６図は本発明の実施例の回路図、第２図
、第４図および第３図は従来の磁気検知器の正面図お−
よび回路図、第５図な本発明の実施例の斜視図である。BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 6 are circuit diagrams of an embodiment of the present invention, and FIGS. 2, 4, and 3 are front views of a conventional magnetic detector.
FIG. 5 is a perspective view of the embodiment of the present invention; FIG.
１・−・発振回路、２−・励起コイル−３，３′・・・
検知コイル、４・・一位相反転回路、５．５”−和回路
、６．６′・・・整流回路、７・・・差動回路、８・・
−増幅回９一
路、１・・−磁心、１４．１４”・・・可変増幅回路−
１５，１５”・・・可変増幅回路。1.--Oscillation circuit, 2-.Excitation coil-3, 3'...
Detection coil, 4... Single phase inversion circuit, 5.5''-sum circuit, 6.6'... Rectifier circuit, 7... Differential circuit, 8...
-Amplification circuit 9 one-way, 1...-Magnetic core, 14.14"...Variable amplification circuit-
15,15”...Variable amplifier circuit.
Claims (1)
発生する励起コイルと、おのおの前記交流磁界に鎖交し
て誘導電圧を生じる第１および第２の検知コイルと、前
記励起コイルの両端電圧と各前記誘導電圧との差電圧を
それぞれ発生する第１および第２の差動回路と、各前記
差電圧を整流する第１および第２の整流回路と、該第１
および第２の整流回路の整流電圧の差電圧を出力する第
３の差動回路とを備えていることを特徴とする磁気検知
器。 ２、前記第１および第２の差動回路はそれぞれ、前記励
振コイルの両端電圧を位相反転した電圧および前記誘導
電圧におのおの倍率を乗じたものの和電圧を発生し且つ
該倍率を可変するための可変手段を設けた和回路を有す
る請求項１記載の磁気検知器。 ３、前記第１および第２の差動回路はそれぞれ、前記励
振コイルの両端電圧に倍率を乗じ且つ該倍率を可変する
ための可変手段を設けた可変増幅回路と、該可変増幅回
路の送出電圧および前記誘導電圧の差電圧を発生する差
動増幅回路とを有する請求項１記載の磁気検知器。 ４、前記励起コイルと前記第１および第２の検知コイル
とを同一磁心に巻線してある請求項１記載の磁気検知器
。[Claims] 1. An excitation coil that generates an alternating magnetic field using an alternating current applied from an oscillation circuit, first and second sensing coils that each generate an induced voltage by interlinking with the alternating magnetic field, and the excitation coil. first and second differential circuits that generate a voltage difference between the voltage across the coil and each of the induced voltages; first and second rectifier circuits that rectify each of the voltage differences;
and a third differential circuit that outputs a voltage difference between the rectified voltages of the second rectifier circuit. 2. The first and second differential circuits each generate a voltage obtained by inverting the phase of the voltage across the excitation coil and a sum voltage obtained by multiplying the induced voltage by a respective multiplier, and for varying the multiplier. 2. A magnetic detector according to claim 1, comprising a sum circuit provided with variable means. 3. The first and second differential circuits each include a variable amplifier circuit provided with variable means for multiplying the voltage across the excitation coil by a magnification and varying the magnification, and a sending voltage of the variable amplification circuit. and a differential amplifier circuit that generates a differential voltage between the induced voltages. 4. The magnetic detector according to claim 1, wherein the excitation coil and the first and second detection coils are wound around the same magnetic core.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1-179258 | 1989-07-11 | ||
| JP17925889 | 1989-07-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03150401A true JPH03150401A (en) | 1991-06-26 |
| JPH0827163B2 JPH0827163B2 (en) | 1996-03-21 |
Family
ID=16062706
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2013052A Expired - Lifetime JPH0827163B2 (en) | 1989-07-11 | 1990-01-22 | Magnetic detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0827163B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006057409A1 (en) * | 2004-11-29 | 2006-06-01 | Nihon University | Electromagnetic induction sensor for metal detector and metal searching method |
-
1990
- 1990-01-22 JP JP2013052A patent/JPH0827163B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006057409A1 (en) * | 2004-11-29 | 2006-06-01 | Nihon University | Electromagnetic induction sensor for metal detector and metal searching method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0827163B2 (en) | 1996-03-21 |
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