JPS6270780A - Ultrasonic matter detector - Google Patents

Abstract

PURPOSE:To prevent erroneous information due to acoustic or electric noises, by providing a means for measuring the distance from a matter and a second receiving gate. CONSTITUTION:The distance from a matter is calculated at a place where a preset threshold value Vth is exceeded for the first time and a second receiving gate is opened during a period TG21 on the basis of the calculated value. Next, when a signal S1 is present during the period TG21, the distance is again calculated and a new receiving gate period TG22 is provided on the basis of the calculated value. When no signal is present during the period TG21, a limit such that the signal is during the period TG21 is detached and all of the signals during the original period TG are investigated. Next, the signal during the period TG22 is investigated and, when a signal S2 is present during a period TG22, the distance is calculated and a new second receiving gate period TG23 is provided. Then, on the basis of the next reception, it is investigated whether a signal S3 is present during the period TG23. When the signal S3 is present, a matter detection output signal showing the presence of the matter is outputted for the first time.

Description

【発明の詳細な説明】 〔技術分野〕 本発明は物体の存在や、あるいはその移動方向及び距離
等の情報を得ることを目的とした超音波物体検知器に関
するものである。DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an ultrasonic object detector whose purpose is to obtain information about the presence of an object, or its moving direction and distance.

〔背景技術〕[Background technology]

超音波パルスを用いて物体の検知を行なうパルス式の超
音波物体検知器において、受波ゲートの出力として得ら
れる信号としては、送波パルスの物体からの反射波の信
号だけでなく、音響的ノイズ（外米騒音）や電気的ノイ
ズ等がある。これらのノイズによる検知出力の誤報を防
ぐため、複数回受波ゲート出力の信号を調べ、すべての
回に信号（反射波とは限らない）が存在したとき検知出
力を出すようにした複数回連続検知方式が従来より提供
されそいる。ところがかかる従来例においては、反射波
であれノイズであれ、受波ゲート内に存在すればすべて
これを受波信号とみなしてしまうので、例えば第１図の
ような例の場合、複数回（この例では３回）連続検知方
式が役に立たないことがあった。即ち第１図に示す従来
例の動作において、同図（ａ）　（ｂ）　（ｃ）に夫々
示すように第１回目乃至第３回目の超音波パルスＰｕｌ
〜Ｐｕ３を送出し、この送出に続いて期間ＴＧだけ受波
ゲートを開くような構成となっている場合において、図
示のようにＮ　１．　Ｎ　２．　Ｎ３のノイズ出力が得
られたとき、これらのノイズ出力Ｎｌ、　Ｎ２　、　Ｎ
３はすべて受波ゲート期間Ｔ（）内に入っているため、
毎回受波ゲート出力が得られ、３回目の受波ゲート出力
により誤報としての検知出力が出力されることになる問
題があったのである。In a pulse-type ultrasonic object detector that detects objects using ultrasonic pulses, the signal obtained as the output of the reception gate is not only the signal of the reflected wave from the object of the transmitted pulse, but also the acoustic signal. There is noise (foreign noise), electrical noise, etc. In order to prevent false alarms in the detection output due to these noises, the signal of the reception gate output is checked multiple times, and the detection output is output when a signal (not necessarily a reflected wave) is present every time. Detection methods are currently available. However, in such a conventional example, whether it is a reflected wave or noise, if it exists within the reception gate, it is regarded as a reception signal. In the example, the continuous detection method was not useful (three times). That is, in the operation of the conventional example shown in FIG. 1, the first to third ultrasonic pulses Pul
In the case where the configuration is such that the signal .about.Pu3 is transmitted and the receiving gate is opened for a period TG following this transmission, as shown in the figure, N1. N2. When N3 noise outputs are obtained, these noise outputs Nl, N2, N
3 are all within the receiving gate period T(), so
There was a problem in that a receiving gate output was obtained each time, and a detection output as a false alarm was output by the third receiving gate output.

〔発明の目的〕[Purpose of the invention]

本発明は上記問題点に鑑みてなしたもので、音響的ノイ
ズや電気的ノイズ等による検知出力の誤報を防止した超
音波物体検知器を提供することを目的とするものである
。The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic object detector that prevents false alarms in detection output due to acoustic noise, electrical noise, etc.

〔発明の開示〕[Disclosure of the invention]

本発明を以下の実施例に基づいて説明する。第２図は本
発明一実施例によるゲートタイミニ／ジ図であり、以下
では３回連続検知方式で説明するが、これはなんら−膜
性を損うことなく、３回以外の一般の複数回連続検知方
式にもあてはめることができる。The present invention will be explained based on the following examples. FIG. 2 is a gate timing diagram according to an embodiment of the present invention, and the explanation below will be based on a 3-time continuous detection method, but this method can be used to detect multiple times other than 3 times without impairing the film properties. It can also be applied to the continuous detection method.

第２図において、同図（ａ）のように１回目に受波ゲー
ト期間ＴＧ内に信号が入ってきた場合、その信号の送波
パルスＰｔｏからの時間遅れに基づいて物体までの距離
が求められる。この実施例で、距離は受波ゲート期間Ｔ
Ｇの左端から見ていき、あらかめ（信号がノイズの場合
も距離が計算されるが、その値は意味を持たない。）、
求まった距離に基づいて、第２の受波ゲートを期間ＴＱ
２１に開くように設定する。次に同図（ｂ）のように２
回目は、まず前回に設定した第２の受波ゲート期間ＴＱ
２１内に信号Ｎ１が存在するかどうかを調べ、この同図
（ｂ）では信号が入っていないが、令弟２の受波ゲート
期間ＴＧ　２１に信′８’Ｓｔが存在する場合は再び距
離を求め、それに基づいて新たな第２の受波ゲート期間
ＴＧ２２を設ける。これに対して上記の第２の受波ゲー
ト期間ＴＧ２１に信号が存在しない場合（図示の例）は
、第２の受波ゲート期間ＴＧ２１内という制限をはずし
、もとの受波ゲート期間ＴＧＩ内すべてを調べる。すな
わち３回連続検知方式の１回目に戻るわけである。次に
同図（Ｃ）においては、その前回に設定した第２受波ゲ
ート期間ＴＧ２２内を調べ、今回は受波ゲート期間ＴＧ
２２内に信号Ｓ２が存在するので距離を計算し、新たな
第２の受波ゲート期間ＴＧ　２３を設け、さらに次の回
の受信でこの受波ゲート期間ＴＧ２３内に信号Ｓ３が存
在するかを調べる。この例では受波ゲート期間ＴＧ２３
内に信号Ｓ３が存在するので、ここで初めて物体が存在
することを示す物体検知出力信号を出す。以下同様な処
理を行なえばよい。ここで第２の受波ゲートの設定は、
第３図（ａ）のように求められた距ｉｄを中心にして両
側に一定距離Ｗを調べるものが考えられるが、特に検知
器側に接近するような物体に対しては、接近側のゲート
幅を広くとってｘ、ｌ！ニジ、非接近側をｙとして狭く
とった第３図（ｂ）のようなものも考えられるものであ
り、さらに、これら２つの例にとどまらず、用途に応じ
て各種のゲート形式を考えることができるものである。In Fig. 2, when a signal enters within the reception gate period TG for the first time as shown in Fig. 2(a), the distance to the object is calculated based on the time delay of that signal from the transmission pulse Pto. It will be done. In this example, the distance is the receiving gate period T
Starting from the left end of G, roughly (the distance is calculated even if the signal is noise, but the value has no meaning),
Based on the determined distance, the second reception gate is set for the period TQ.
Set it to open on 21. Next, as shown in the same figure (b), 2
For the second time, first, the second reception gate period TQ that was set last time is
It is checked whether the signal N1 exists within 21, and although there is no signal in this figure (b), if the signal '8'St exists in the reception gate period TG 21 of younger brother 2, the distance is determined again. is determined, and a new second reception gate period TG22 is provided based on it. On the other hand, if there is no signal in the second reception gate period TG21 (as shown in the example), the restriction of being within the second reception gate period TG21 is removed and the signal is returned within the original reception gate period TGI. Examine everything. In other words, the process returns to the first detection of the three consecutive detection methods. Next, in the same figure (C), the inside of the second wave receiving gate period TG22 set last time is examined, and this time the inside of the second wave receiving gate period TG22 is checked.
Since the signal S2 exists within the reception gate period TG 22, the distance is calculated, a new second reception gate period TG 23 is set, and it is determined whether the signal S3 exists within this reception gate period TG 23 in the next reception. investigate. In this example, the reception gate period TG23
Since the signal S3 is present within the sensor, an object detection output signal indicating the presence of an object is output for the first time. Similar processing may be performed thereafter. Here, the setting of the second reception gate is as follows:
It is conceivable to check a fixed distance W on both sides centering on the distance id obtained as shown in Fig. 3 (a), but especially for objects that approach the detector side, the gate on the approaching side Make it wider x, l! It is also possible to think of something like the one shown in Figure 3 (b), where the non-approach side is set narrowly as y, and in addition to these two examples, various gate types can be considered depending on the application. It is possible.

第４図は上記実施例を実現する回路構成例を示すブロッ
ク図であシ、送波パルス作成＠　ｉｌｌで作成された送
波パルスは超音波トランスジューサ（２）で超音波に変
換され空間に送出される。これと同時に時間基準信号と
して上記の送波パルスの作成信号は受波ゲート作成部（
３）、第２の受波ゲート作成部（４）、演算回路部（６
）に送られる。一方空間に送出された超音波パルスは物
体により反射されて超音波トランスジューサ（２）によ
り受波されて受波信号増幅検波回路（６）で増幅し検波
され演算回路部（５）に入力される。さらに演算回路部
（５）では受波ゲート作成部（３）及び第２の受波ゲー
ト作成部（４）ア出力も入力される。受波ゲート作成部
（３）は前述の期間ＴＧの受波ゲートを作成し、第２の
受波ゲート作成部（４）は前述め期間ＴＧ２１〜ＴＧ　
２３　　の受波ゲートを作成するものであり、演算回路
部（５）はこれらのゲート信号を受波信号増幅検波回路
（６）の出力とともに入力し、前述の第３図のようなゲ
ート作成処理の演算動作を行なうものであり、演算回路
部（５）から検知出力信号を出力するとともに記憶回路
部（７）にこの結果を記憶するものである。FIG. 4 is a block diagram showing an example of a circuit configuration for realizing the above embodiment. The transmission pulse created by the transmission pulse creation @ill is converted into an ultrasonic wave by the ultrasonic transducer (2) and sent out into space. be done. At the same time, the generation signal for the above-mentioned transmission pulse as a time reference signal is generated by the reception gate generation section (
3), second reception gate creation section (4), arithmetic circuit section (6)
) will be sent to. On the other hand, the ultrasonic pulse sent out into space is reflected by an object, received by the ultrasonic transducer (2), amplified and detected by the received signal amplification and detection circuit (6), and input to the arithmetic circuit section (5). . Furthermore, the arithmetic circuit section (5) also receives the outputs of the reception gate creation section (3) and the second reception gate creation section (4). The reception gate creation unit (3) creates a reception gate for the above-mentioned period TG, and the second reception gate creation unit (4) creates a reception gate for the above-mentioned period TG21 to TG.
23, the arithmetic circuit section (5) inputs these gate signals together with the output of the received signal amplification and detection circuit (6), and performs the gate creation process as shown in Fig. 3 above. The arithmetic circuit unit (5) outputs a detection output signal and the result is stored in the memory circuit unit (7).

〔発明の効果〕〔Effect of the invention〕

本発明は上述のように構成したものであるから、実際に
被検出用の物体について予想される動きの範囲内にある
信号のみを物体からの反射波信号として収り出すことが
でき、信号検出の精度が大幅に向上してノイズ等による
誤報のおそれを大幅に低減することができる効果を有す
るものであるSince the present invention is configured as described above, it is possible to extract only signals within the expected movement range of the object to be detected as reflected wave signals from the object, and to detect signals. This has the effect of significantly improving the accuracy of information and greatly reducing the risk of false alarms due to noise, etc.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は従来例の動作説明図、第２図は本発明一実施例
の動作説明図、第３図（ａ）　（ｂ）は同上の第２の受
波ゲートの期間設定についての互いに異なる例の説明図
、第４図は本発明一実施例の１０９２図である。 代理人　弁理士　　石　１）長　上 第１図 第２図FIG. 1 is an explanatory diagram of the operation of the conventional example, FIG. 2 is an explanatory diagram of the operation of one embodiment of the present invention, and FIGS. An explanatory diagram of an example, FIG. 4 is a 1092 diagram of an embodiment of the present invention. Agent Patent Attorney Ishi 1) Chief Figure 1 Figure 2

Claims (1)

【特許請求の範囲】[Claims] （１）超音波パルスの送波と、受波ゲートを介した反射
波信号の検出とをあらかじめ設定された回数だけ繰り返
し、それらすべての回に反射波信号が存在したとき検知
出力を出すようにした超音波物体検知器において、一度
受波ゲート内に物体からの反射波信号が検知されたとき
、その物体からの距離を測定する手段と、この測定手段
で測定された距離からあらかじめ設定された一定距離範
囲内の物体からの反射波信号のみを通過させる第２の受
波ゲートとを設け、この第２の受波ゲートを介して入力
する反射波信号だけを物体からの反射波信号と確認する
ようにして成ることを特徴とする超音波物体検知器。(1) Transmission of ultrasonic pulses and detection of reflected wave signals via a reception gate are repeated a preset number of times, and a detection output is output when a reflected wave signal is present all of those times. In an ultrasonic object detector that has A second reception gate is provided that allows only reflected wave signals from objects within a certain distance range to pass through, and only the reflected wave signals input through this second reception gate are confirmed as reflected wave signals from the object. An ultrasonic object detector comprising: