JP2590578B2 - Magnetic detector - Google Patents
Magnetic detectorInfo
- Publication number
- JP2590578B2 JP2590578B2 JP2050897A JP5089790A JP2590578B2 JP 2590578 B2 JP2590578 B2 JP 2590578B2 JP 2050897 A JP2050897 A JP 2050897A JP 5089790 A JP5089790 A JP 5089790A JP 2590578 B2 JP2590578 B2 JP 2590578B2
- Authority
- JP
- Japan
- Prior art keywords
- detection
- magnetic
- synchronous
- magnetic field
- excitation 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.)
- Expired - Lifetime
Links
- 238000001514 detection method Methods 0.000 claims description 40
- 230000005284 excitation Effects 0.000 claims description 24
- 230000001360 synchronised effect Effects 0.000 claims description 14
- 230000006698 induction Effects 0.000 claims description 2
- 230000004044 response Effects 0.000 claims description 2
- 238000013459 approach Methods 0.000 description 5
- 239000004020 conductor Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 239000000696 magnetic material Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
Landscapes
- Geophysics And Detection Of Objects (AREA)
- Control Of Position, Course, Altitude, Or Attitude Of Moving Bodies (AREA)
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、特に磁性体または導電体
をガイドレーンとして走行する無人搬送車に使用されて
ガイドレーンからの走路ずれを検知するための磁気検知
器に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic detector, and in particular, is used in an automatic guided vehicle that travels using a magnetic or conductive body as a guide lane and detects a deviation from a guide lane. For magnetic detectors.
この種の磁気検知器として従来、交流磁場を発生する
励振コイルと、それが作る磁場によって誘導電圧を生じ
る検知コイルからな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、広く
利用されている。この従来技術は、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、帯状の磁性体または金属等の電導体をガイドレー
ンとして誘導すべき走路に設けて、車両等に取付けられ
た検知器でガイドレーンの方向を検知し、これに応じて
操舵して目的の場所に誘導するものである。Conventionally, as this type of magnetic detector, there is a self-excitation type including an excitation coil for generating an AC magnetic field and a detection coil for generating an induced voltage by a magnetic field generated by the excitation coil. This is widely used because of its simple structure and great design freedom. This conventional technique is used and useful in various vehicle guidance systems and the like. In these guidance systems, a strip-shaped conductor such as a magnetic material or metal is provided as a guide lane on a runway to be guided, and the direction of the guide lane is detected by a detector attached to a vehicle or the like, and steering is performed accordingly. And then to the destination.
従来の磁気検知器としては、第３図に示すようにコイ
ル配置で、第４図の回路構成をもつものが知られてい
る。励振コイル２と、１対の検知コイル3,13とを金属ケ
ース12内に固定してある。検知コイル3,13はそれぞれ、
中心軸Ｌに対し対称な位置に固定されている。As a conventional magnetic detector, a magnetic detector having a coil arrangement as shown in FIG. 3 and a circuit configuration shown in FIG. 4 is known. The excitation coil 2 and a pair of detection coils 3 and 13 are fixed in a metal case 12. The detection coils 3 and 13 are respectively
It is fixed at a position symmetrical with respect to the central axis L.
この磁気検知器の動作について説明する。まず励振コ
イル２に発振器１を接続して、交流電流を励振コイル２
に流して、励振コイル２から励起磁界９を発生させる。
この励起磁界９の一部分が検知コイル3,13と鎖交して、
検知コイル3,13に誘導電圧が生じる。この誘導電圧は、
第４図の増幅器4,14に入力してそれぞれ増幅されたあ
と、整流回路10,20で整流されて差動回路11に入力さ
れ、検知コイル3,13から送られてくる両信号の差が出力
される。The operation of this magnetic detector will be described. First, the oscillator 1 is connected to the excitation coil 2, and an alternating current is applied to the excitation coil 2.
And an excitation magnetic field 9 is generated from the excitation coil 2.
A part of the excitation magnetic field 9 links with the detection coils 3 and 13,
An induced voltage is generated in the detection coils 3 and 13. This induced voltage is
After being input to amplifiers 4 and 14 in FIG. 4 and amplified respectively, they are rectified by rectifier circuits 10 and 20 and input to differential circuit 11, and the difference between the two signals sent from detection coils 3 and 13 is obtained. Is output.
使用時に、検知コイル3,13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3,13に鎖交する磁束も変化する。あるいは、導電体
が接近すると、導電体に生じる渦電流により磁界が変化
し、検知コイル3,13に誘導される電圧も変化する。磁性
体または導電体が、２つの検知コイル3,13から対称な位
置にある場合には、磁界分布は対称になり、２つの検知
コイル3,13の誘導電圧も等しいため、検知器出力も零と
なる。しかし、磁性体または導電体で作られたガイドレ
ーンが検知コイル3,13の片方により接近すると、両コイ
ル3,13の誘導電圧が不平衡となり、差動回路11の出力電
圧が不平衡の程度に応じて正または負となる。従って、
この電圧を零にするよう制御することにより、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。When a magnetic material having a relative magnetic permeability higher than that of air approaches the detection coils 3 and 13 during use, the magnetic field distribution changes, and the magnetic flux linked to the detection coils 3 and 13 also changes. Alternatively, when the conductor approaches, the magnetic field changes due to the eddy current generated in the conductor, and the voltage induced in the detection coils 3 and 13 also changes. If the magnetic or conductive material is located symmetrically from the two sensing coils 3 and 13, the magnetic field distribution is symmetric and the induced voltages of the two sensing coils 3 and 13 are equal, so that the detector output is also zero. Becomes However, when a guide lane made of a magnetic material or a conductor approaches one of the detection coils 3 and 13, the induced voltages of both coils 3 and 13 become unbalanced, and the output voltage of the differential circuit 11 becomes unbalanced. Is positive or negative depending on Therefore,
By controlling this voltage to be zero, a vehicle or the like can run along the guide lane.
上述した従来の磁気検知器では、励振コイル２と検知
コイル3,13とが近接しているため、被検知物が近接しな
い場合にも検知コイル3,13に生じる電圧は大きい。この
場合、被検知物が近接したことによる検知コイル3,13に
生じる電圧の変化は非常にわずかであり、回路系の温度
特性等で電圧変化を検知することが困難である。この困
難を解消するためには、被検知物が近接しない時に検知
コイル3,13に生じる電圧を小さくする必要がある。その
ために、第３図に示すように検知コイル3,13に鎖交する
磁界がバランスした点の近くに、検知コイル3,13を固定
する必要がある。しかしこのバランス点近傍は少しの取
付誤差でも磁界の変化が大きいため、位置設定が困難で
あるという欠点がある。In the above-described conventional magnetic detector, since the excitation coil 2 and the detection coils 3 and 13 are close to each other, the voltage generated in the detection coils 3 and 13 is large even when the detected object is not close. In this case, the change in the voltage generated in the detection coils 3 and 13 due to the proximity of the object to be detected is very small, and it is difficult to detect the voltage change based on the temperature characteristics of the circuit system. In order to solve this difficulty, it is necessary to reduce the voltage generated in the detection coils 3 and 13 when the detected object does not approach. For this purpose, as shown in FIG. 3, it is necessary to fix the detection coils 3, 13 near a point where the magnetic fields linking the detection coils 3, 13 are balanced. However, there is a disadvantage that the position setting is difficult in the vicinity of the balance point because the magnetic field changes greatly even with a small mounting error.
本発明の磁気検知器は、交流信号を発する発振器と、
該発振器の出力信号を印加され交流磁界を発生する励振
コイルと、該励振コイルの発する前記交流磁界に感応し
て誘導電圧を生じる第１および第２の検知コイルと、該
第１および第２の検知コイルで生じる前記誘導電圧をそ
れぞれ増幅する第１および第２の増幅器と、該第１およ
び第２の増幅器の出力信号をそれぞれ前記発振器の出力
信号により同期検波する第１および第２の同期検波器
と、該第１および第２の同期検波器の両出力信号の差を
発生し出力する加算器とを備えている。The magnetic detector of the present invention, an oscillator that emits an AC signal,
An excitation coil to which an output signal of the oscillator is applied to generate an AC magnetic field; first and second detection coils that generate an induced voltage in response to the AC magnetic field generated by the excitation coil; First and second amplifiers for respectively amplifying the induced voltage generated in the detection coil, and first and second synchronous detections for synchronously detecting output signals of the first and second amplifiers with output signals of the oscillator, respectively. And an adder for generating and outputting the difference between the two output signals of the first and second synchronous detectors.
検知コイルの誘導電圧を励振コイルの励振電圧により
同期検波することにより、励振コイルと検知コイルとを
接近させても雑音の影響が少なく小型化でき、さらに励
振コイルと検知コイルとの間の位置設定も従来のように
厳しくする必要無く製造工数を大幅に低減できる。Synchronous detection of the induction voltage of the detection coil with the excitation voltage of the excitation coil minimizes the effects of noise even when the excitation coil and the detection coil are brought close together, and furthermore, sets the position between the excitation coil and the detection coil. In addition, the number of manufacturing steps can be significantly reduced without having to make it strict as in the conventional case.
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 described with reference to the drawings.
第１図は本発明の一実施例のブロック図である。発振
器１から出力される交流電流により、励振コイル２は交
流磁界を発生し、交流磁界と鎖交する検知コイル3,13は
誘導電圧を発生する。この誘導電圧は、増幅器4,14にて
増幅された後、同期検波器5,15の一方の入力端子に印加
される。また発振器１の出力交流が基準信号として、同
期検波器5,15の他方の入力端子に供給される。同期検波
器5,15の検波出力は、同期検波により得られる直流成分
および低周波成分のうちの倍周波成分を抑圧した直流成
分である。この両検波出力VL,VRを加算器８に供給し、
左右の検知コイル3,13の電圧差VCとして出力する。すな
わち加算器８の出力電圧が、例えば走路制御用の信号に
なる。FIG. 1 is a block diagram of one embodiment of the present invention. The excitation coil 2 generates an AC magnetic field by the AC current output from the oscillator 1, and the detection coils 3 and 13 linked to the AC magnetic field generate an induced voltage. The induced voltage is amplified by the amplifiers 4 and 14, and then applied to one input terminal of the synchronous detectors 5 and 15. The alternating current output from the oscillator 1 is supplied to the other input terminals of the synchronous detectors 5 and 15 as a reference signal. The detection output of the synchronous detectors 5, 15 is a DC component obtained by suppressing the double frequency component of the DC component and the low frequency component obtained by the synchronous detection. Both detection output V L, and supplies the V R to the adder 8,
And outputs as a voltage difference V C between the left and right detection coil 3 and 13. That is, the output voltage of the adder 8 becomes, for example, a signal for controlling the traveling road.
従って、被検知物が近接した際の検知コイル3,13の誘
導電圧の変化分のみが加算器８から出力され、磁界の変
化が左右どちら側で大きいか、すなわち被検知物が磁気
検知器の左右いずれにあるかを判定できる。Therefore, only the change in the induced voltage of the detection coils 3 and 13 when the detection object approaches is output from the adder 8, and whether the change in the magnetic field is large on the left or right side, that is, the detection object is It can be determined whether it is on the left or right.
以上説明したように本実施例では、検知コイル3,13の
各誘導電圧を同期検波して差信号を取出しており、誘導
電圧に混入している雑音成分は、同期検波器５で直流成
分を抽出する際に、大部分が抑圧される。この結果、励
振コイル１と検知コイル3,13とを従来よりも接近させて
も、あるいは位置設定精度を従来ほど厳しく管理しなく
ても、雑音混入による検知誤差を劣化させずに済む。As described above, in the present embodiment, the differential signal is extracted by synchronously detecting each of the induced voltages of the detection coils 3 and 13, and the noise component mixed in the induced voltage is converted into a DC component by the synchronous detector 5. During extraction, most are suppressed. As a result, even if the excitation coil 1 and the detection coils 3 and 13 are made closer to each other than before, or the position setting accuracy is not strictly controlled as before, the detection error due to noise contamination can be prevented from deteriorating.
第２図は本発明の他の実施例のブロック図である。本
実施例では、信号対雑音比を向上させるために低域波
器6,16を挿入し、更に２つの信号経路の利得差を補正す
るために可変利得直流増幅器7,17を追加してある。FIG. 2 is a block diagram of another embodiment of the present invention. In this embodiment, low pass filters 6 and 16 are inserted to improve the signal-to-noise ratio, and variable gain DC amplifiers 7 and 17 are added to correct the gain difference between two signal paths. .
以上説明したように本発明は、検知コイルの誘導電圧
を励振コイルの励振電圧により同期検波することによ
り、励振コイルと検知コイルとを接近させても雑音の影
響が少なく小型化でき、さらに励振コイルと検知コイル
との間の位置設定も従来のように厳しくする必要無く製
造工数を大幅に低減できるという効果をもつ。As described above, the present invention synchronously detects the induced voltage of the detection coil by the excitation voltage of the excitation coil, thereby reducing the influence of noise even when the excitation coil and the detection coil are brought close to each other, and further reducing the size of the excitation coil. There is an effect that the number of manufacturing steps can be greatly reduced without the need to set the position between the sensor and the detection coil as strict as in the related art.
第１図および第２図は本発明の実施例のブロック図、第
３図は本発明および従来の磁気検知器のでのコイル配置
図、第４図は従来の磁気検知器のブロック図である。 １……発振器、２……励振コイル、3,13……検知コイ
ル、4,14……増幅器、5,15……同期検波器、6,16……低
域波器、7,17……可変利得直流増幅器、８……加算
器、９……励起磁界、10,20……整流回路、11……差動
回路、12……金属ケース。1 and 2 are block diagrams of an embodiment of the present invention, FIG. 3 is a coil arrangement diagram of the present invention and a conventional magnetic detector, and FIG. 4 is a block diagram of a conventional magnetic detector. 1 ... Oscillator, 2 ... Exciter coil, 3,13 ... Detector coil, 4,14 ... Amplifier, 5,15 ... Synchronous detector, 6,16 ... Low-band wave filter, 7,17 ... Variable gain DC amplifier, 8 Adder, 9 Excitation magnetic field, 10, 20 Rectifier circuit, 11 Differential circuit, 12 Metal case.
Claims (2)
力信号を印加され交流磁界を発生する励振コイルと、該
励振コイルの発する前記交流磁界に感応して誘導電圧を
生じる第１および第２の検知コイルと、該第１および第
２の検知コイルで生じる前記誘導電圧をそれぞれ増幅す
る第１および第２の増幅器と、該第１および第２の増幅
器の出力信号をそれぞれ前記発振器の出力信号により同
期検波する第１および第２の同期検波器と、該第１およ
び第２の同期検波器の両出力信号の差を発生し出力する
加算器とを備えていることを特徴とする磁気検知器。An oscillator for generating an AC signal, an excitation coil for applying an output signal of the oscillator to generate an AC magnetic field, and first and second generating induction voltages in response to the AC magnetic field generated by the excitation coil. , A first and a second amplifier respectively amplifying the induced voltage generated in the first and second detection coils, and an output signal of the first and second amplifiers, respectively, Magnetic detection comprising: a first and a second synchronous detector for performing synchronous detection on the basis of the first and second synchronous detectors; and an adder for generating and outputting a difference between both output signals of the first and second synchronous detectors. vessel.
算器との間にそれぞれ低域波器と可変利得増幅器とを
直列に挿入接続したことを特徴とする特許請求の範囲１
項記載の磁気検知器。2. A low-pass filter and a variable gain amplifier are inserted and connected in series between said first and second synchronous detectors and said adder, respectively.
Item 7. A magnetic detector according to item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2050897A JP2590578B2 (en) | 1990-03-02 | 1990-03-02 | Magnetic detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2050897A JP2590578B2 (en) | 1990-03-02 | 1990-03-02 | Magnetic detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03252805A JPH03252805A (en) | 1991-11-12 |
| JP2590578B2 true JP2590578B2 (en) | 1997-03-12 |
Family
ID=12871534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2050897A Expired - Lifetime JP2590578B2 (en) | 1990-03-02 | 1990-03-02 | Magnetic detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2590578B2 (en) |
-
1990
- 1990-03-02 JP JP2050897A patent/JP2590578B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03252805A (en) | 1991-11-12 |
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