JPH0236383A - Ultrasonic array sensor - Google Patents

Abstract

PURPOSE:To form a detection area in an optional state by arraying plural ultrasonic wave vibrators on the same plane at equal intervals, giving the timing of wave transmission a phase difference, and varying a detection distance according to the scanning angle of a directional beam. CONSTITUTION:A maximum detection distance setting circuit sends out such a delay quantity signal that a scanning angle phi1 of the directional beam is obtained and such a maximum detection distance signal that a maximum detection distance L1 is obtained to a delay circuit and a signal processing circuit so as to form a detection area B1. When an ultrasonic is sent and received in this state, the area B1 is formed, and the delay quantity signal for obtaining a scanning angle phi2 of the directional beam and the maximum distance signal for obtaining a maximum detection distance L2 are sent out to the delay circuit and signal processing circuit. When an ultrasonic wave is sent and received in this state, a detection area B2 is formed. Thus, the maximum detection distance setting circuit varies the delay quantity signal and maximum detection distance in order. This operation is repeated to form a detection area consisting of overlapping detection areas B1-B7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic array sensor in which a plurality of ultrasonic transducers that transmit ultrasonic waves and receive reflected waves are arranged on the same plane. It is.

[Conventional technology]

Conventional ultrasonic sensors using a single ultrasonic transducer cannot detect a narrow range because the directional beam is thick and gentle.

For example, Japanese Patent Laid-Open No. 63-72300 discloses an ultrasonic array sensor in which a plurality of ultrasonic transducers are arranged on the same plane.

This ultrasonic array sensor has a plurality of ultrasonic transducers arranged at equal intervals. This made it possible to narrow the directional beam.

If a wide area is to be monitored using an ultrasonic array sensor having such a narrow directional beam, it is necessary to scan this directional beam over a wide area. For example, as shown in FIG. 5, by controlling the transmission time of the ultrasonic transducer St with respect to the transmission of the ultrasonic transducer S, using a delay circuit, as shown in FIG. It is sufficient to change the direction, that is, the scanning angle φ.

In other words, as shown in FIG. 6, the ultrasonic transducer SI+32
By shifting the transmission time of Δt by Δt, the in-phase wavefronts are aligned in a direction shifted by an angle φ from the front direction, thereby making it possible to scan the directional beam by an angle φ.

If the pitch between the ultrasonic transducers St and Sz is d7, and the distance between the same phase wavefronts is Δl, then Δt=Δfi/c=d+sinφ/c (c is the speed of sound). S2 for Sl for the time Δt found by this formula
By delaying the transmission time to , it is possible to form a directional beam in a direction deviated from the front direction by an angle φ.

[Problems to be Solved by the Invention] However, in the above conventional example, the shape of the directional beam B becomes approximately fan-shaped as shown in FIG. 7, and it is difficult to form a detection area of any shape. I couldn't do it.

The present invention has been made in view of the above points, and an object thereof is to provide an ultrasonic array sensor that can form a detection area of any shape.

[Means to solve the problem]

The ultrasonic array sensor of the present invention arranges a plurality of ultrasonic transducers that transmit ultrasonic waves and receive reflected waves at equal intervals on the same plane, and transmits waves to each of the ultrasonic transducers. An ultrasonic array sensor in which a directional beam is sequentially scanned by providing a phase difference in timing, and is characterized in that a detection distance is changed according to a scanning angle of the directional beam. .

[Effect]

In the ultrasonic array sensor of the present invention, the scanning of the directional beam is controlled by controlling the delay amount of the delay circuit for scanning the directional beam and the detection distance corresponding to the pointing direction of the directional beam, which is determined according to the delay amount. The detection distance is changed depending on the corner, making it possible to form a detection area of any shape.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on drawings showing one embodiment of the present invention.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In this embodiment, an example using five ultrasonic transducers is shown, but the number is not limited to five.

S1 to S are ultrasonic transducers that transmit ultrasonic waves and receive reflected waves, and are arranged on the same plane at equal intervals d, forming an ultrasonic array sensor. , D2-D are delay circuits that control the transmission time of the ultrasound transducers 32-S relative to the transmission time of the ultrasound transducer S1. The transmission times of the ultrasonic transducers S, ~S are sequentially shifted, and the scanning angles of the plurality of directional beams are tilted by a predetermined angle. In other words, the scanning angle of the directional beam can be controlled by the amount of delay in the delay circuit D t "" D s. A, -As are wave transmitting/receiving circuits, and the ultrasonic transducer 8
1 to S, or ultrasonic transducers S, -S.
, which amplifies the signal received by the . A detection circuit 1 detects the transfer signal amplified by the wave transmission/reception circuits A1 to A. 2 is an object detection circuit that calculates the distance to the object based on the time delay between the received pulse and the transmitted pulse. 3 is a detection maximum distance setting circuit that presets the relationship between a delay amount signal indicating the amount of delay for realizing a predetermined scanning angle and a detection maximum distance signal indicating the maximum detection distance according to the scanning angle. Then, the delay amount signal is sent to delay circuits D2 to D5, and the detected maximum distance signal is sent to a signal processing circuit to be described later.

4 is a signal processing circuit, which includes a gate provided corresponding to the distance signal to the object outputted from the object detection circuit 2 and the maximum detection distance signal set by the maximum detection distance setting circuit 3 at a certain scanning angle. When the former is smaller than the
That is, when the distance to the object at the scanning angle is smaller than the maximum detection distance, a signal indicating the presence of the object is output to the display 5. The display 5 displays the presence of an object based on the signal from the signal processing circuit 4.

Next, the operation of this embodiment will be explained. For example, in this embodiment, we will explain the case where the detection area is to be formed in a shape close to a rectangle as shown in FIG. 3. As shown in FIG. Accordingly, detection areas B+-Bs are sequentially formed.

First, in order to form the detection area B, the maximum detection distance setting circuit 3 generates a delay amount signal such that the scanning angle of the directional beam is φ and a maximum detection distance signal such that the maximum detection distance is L1. The signal is sent to the delay circuits D□ to D and the signal processing circuit 4. When ultrasonic waves are transmitted and received in this state, a detection area B is formed. Next, the maximum detection distance setting circuit 3 sets the scanning angle of the directional beam to φ2.
A delay amount signal such that L2 is the maximum detected distance and a maximum detected distance signal such that the maximum detected distance is L2 are sent to the delay circuits D2 to DS and the signal processing circuit 4, respectively. When ultrasonic waves are transmitted and received in this state, a detection area B2 is formed.

In this way, when the maximum detection distance setting circuit 3 sequentially changes the delay amount signal and the maximum detection distance, the detection area changes sequentially from B to -B. By repeating the above scanning, it is possible to form a substantially rectangular detection area in which the detection areas Bt''B'r are overlapped, as shown in FIG.

In this embodiment, a substantially rectangular detection area is formed, but by setting the relationship between the scanning angle and the maximum detection distance in various ways, it is possible to realize a detection area of any shape.

Further, in the above embodiment, in order to set the maximum detection distance for each scanning angle, the maximum detection distance setting circuit 3 sends a maximum detection distance signal to the signal processing circuit 4, but as shown in FIG. As shown, maximum detection distance setting circuit 3
From the wave transmitting/receiving circuit A.

The maximum detection distance for each scanning angle may be set by sending a signal that changes the transmitting gain or receiving gain to ~A. In this case, the gate of the signal processing circuit 4 is set at a constant distance. A compatible one is fine.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of ultrasonic transducers that transmit ultrasonic waves and receive reflected waves are arranged at equal intervals on the same plane, and the transmission to each of the ultrasonic transducers is This is an ultrasonic array sensor in which a directional beam is sequentially scanned by providing a phase difference in the timing of waves, and the detection distance is changed according to the scanning angle of the directional beam, so that it can be applied to any shape. We were able to provide an ultrasonic array sensor that can form a detection area of

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIGS. 2 and 3 are schematic diagrams of a detection area for explaining the operation of the same, and FIG. 4 is a block diagram showing an embodiment of the present invention. FIG. 5 is a block diagram showing a conventional example; FIG. 6 is a diagram explaining the principle of the same as the above; FIG. 7 is a schematic diagram of a detection area for explaining the operation of the conventional example. S, ~S, - Ultrasonic transducer D2 to D, - Delay circuit A, -A, ... Transmission/reception circuit - Detection circuit 2 - Object detection circuit 3 - Maximum detection distance setting circuit 4 - Signal Processing circuit 5 - Display unit B, ~B, --- Detection area 12 diagram

Claims (1)

[Claims] (1) A plurality of ultrasonic transducers that transmit ultrasonic waves and receive reflected waves are arranged at equal intervals on the same plane, and a phase difference is created in the timing of transmitting waves to each of the ultrasonic transducers. What is claimed is: 1. An ultrasonic array sensor that sequentially scans a directional beam, the sensing distance being changed according to the scanning angle of the directional beam.