JPH01235888A - Underwater finder - Google Patents

Abstract

PURPOSE:To suppress the generation of cavitation during stoppage and traveling of a ship by changing the voltage impressed to an electric-ultrasonic wave converting means or the transmission period of a clock pulse according to the measured ship speed. CONSTITUTION:The ship speed with respect to sea water is measured by a ship speed meter 4 to water and the decision of the traveling and stoppage of the ship is executed by a CPU 6 which outputs the clock pulse KP of the output period corresponding thereto. The voltage E2 lower than the voltage E1 is simultaneously selected according to the traveling or stoppage as the reference voltage to a driving amplifier 1. The pulses KP are outputted for the period corresponding to the traveling or stoppage from the CPU 6 in this state. The pulses KP inputted to the amplifier 1 are amplified to the prescribed amplitude in accordance with the magnitude of the voltages E1, E2 and are further subjected to power amplification 2. The output voltages VH, VL are then impressed to the oscillator 3. These voltages VH, VL are the impressed voltages of the upper limit at which the generation of the cavitation during the traveling and stoppage is obviated. The magnitudes of the voltages E1, E2 are so set that these voltages VH, VL are outputted from the amplifier 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an underwater detection device for detecting schools of fish and the like.

[Prior Art] FIG. 3 shows an ultrasonic transmitter used in a conventional underwater detection device.

The clock pulse KP input to the drive amplifier 1 is amplified to a predetermined voltage determined by the magnitude of the reference voltage E.
After the power is further amplified by a power amplifier 2, an ultrasonic wave is outputted by a vibrator 3, which is an electric-ultrasonic converter. This vibrator 3 is provided, for example, on the bottom of the ship, and transmits ultrasonic waves to the seabed.

FIG. 4 shows the power amplifier 2 when the vibrator 3 is not moving.
3 shows the sound pressure device transmitted from the vibrator 3 with respect to the output voltage ■, that is, the voltage applied to the vibrator.

This transmitted sound pressure 1 is measured by installing a sound receiver at a distance of, for example, 1 m from the vibrator 3. As can be seen from Fig. 4, when the inter-oscillator mold pressure is below vl, the transmitted sound pressure I exhibits a linear output characteristic, but when this voltage exceeds v1, the transmitted sound pressure I gradually becomes saturated. So, when the voltage is around v2, the transmitted sound pressure I is ■. I get saturated with it.

[Problems to be Solved by the Invention] Cavitation is considered to be one of the causes of saturation of the transmitted sound pressure I in this manner. Cavity silane is a phenomenon in which air bubbles are generated in water due to the emission of powerful ultrasonic waves. When such air bubbles are generated, it becomes difficult for ultrasonic waves to travel through water, resulting in a decrease in the transmitted sound pressure. Therefore, even if the input voltage to the vibrator 3 is increased, the transmitted sound pressure does not become so large because cavitation occurs.

Furthermore, it has been confirmed through experiments that if the voltage applied to the vibrator 3 is constant between when the ship is stopped and when the ship is running, a difference occurs in the delivery sensitivity. That is, a detected object was detected while the ship was moving, but the same object was not detected when the ship was stopped. This is because when the ship is stopped, cavitation occurs due to the emission of the ultrasonic detection signal from the transducer 3, and air bubbles generated by this cavitation exist around the transducer 3, so the emitted detection signal and the detected object This is thought to be due to the fact that the reflected signal from the air bubbles was weakened by the bubbles, resulting in a decrease in reception sensitivity. It is also believed that this is because air bubbles generated by cavitation are washed away when the ship is moving, increasing the delivery sensitivity.

The present invention has been made to eliminate the above-mentioned problems, and an object of the present invention is to provide an underwater detection device that can suppress the generation of cavities and silane when a ship is stopped and running.

Another object of the present invention is to provide an underwater detection device that can increase the handover sensitivity when the boat is moving, in an underwater detection device that searches underwater conditions when the boat is running or not moving. It is to be.

Another object of the present invention is to provide an underwater detection device that can increase the handover sensitivity when a ship is moving and is not moving.

[Means for Solving the Problems 1] The underwater detection device of the present invention comprises a clock pulse output means for outputting a clock pulse, an amplification means for amplifying the clock pulse from the clock pulse output means, and an output signal from the amplification means. an electric-ultrasonic conversion means for converting into an ultrasonic signal 7; a water-to-water ship speed measuring means for measuring the ship's speed relative to water; - Features include: means for changing the output voltage; and means for changing the output period of the clock pulse sent out by the clock pulse input/output means in accordance with the ship speed measured by the ship speed relative to water measuring means. shall be.

Another feature of the underwater detection device according to the present invention is that the output voltage of the amplification means is changed in accordance with the ship speed measured by the ship speed relative to water measuring means.

Another feature of the underwater detection device according to the present invention is that the output voltage of the amplification means is kept constant, and the clock pulse output means outputs a clock pulse according to the ship speed measured by the water speed measuring means. It is to change.

[Function 1] According to the above configuration, the clock pulse outputted by the clock pulse output means is amplified by the amplification means, and the output signal is applied to the electric-ultrasonic conversion means. In order to prevent cavitation from occurring with respect to the ship speed measured by the measuring means, the output voltage of the amplifying means is changed to a predetermined magnitude. In addition, the input/output means of the clock pano is capable of changing the output period of the clock pulse according to the ship speed measured by the ship speed measuring means, and when the output voltage is reduced, , the output period of the clock pulse is set to be long.

Also, when the ship is moving and air bubbles generated by cavitation are being washed away, a larger output voltage is generated from the amplification means and applied to the transducer, so a larger reflected signal from the detected object is generated. can be obtained, and the transfer sensitivity during driving can be increased.

In addition, when the ship stops moving, the output period of the clock pulse output from the clock pulse output means becomes longer, so it is possible to obtain a larger reflected signal from the object to be detected. Delivery sensitivity can be increased.

[Embodiment] Fig. 1 is a control block diagram showing a part of an embodiment of the underwater detection device of the present invention, and the same parts as in the conventional example shown in Fig. 3 are given the same reference numerals. .

4 is a water speedometer that measures the speed of the ship relative to seawater;
CPtJ (Central Processing Unit) 6 via interface 5
is input to the input port P1. For example, a water speedometer is used to measure the speed of a water wheel that is rotated by the flow of water. CPU
6 determines whether the ship is running or stopping based on a signal indicating the ship speed measured by the water speedometer 4, and based on the determination result, output period τ1 or τ, or τ2 having a longer period. A clock pulse KP is output from the boat P2, and a switching signal S is output to the switch 7 so that the voltage E or the voltage E2 lower than El is selected as the reference voltage to the drive amplifier 1 depending on whether the boat is running or stopped. Output from port P.

Next, the operation of the apparatus having the above configuration will be explained based on the time chart of FIG.

When it is determined that the ship is running based on the ship speed detected by the water speedometer 4, first, a predetermined switching signal S is sent to the switch 7 from the output port P of the CPU 6. The switch 7 is switched to the El side and El is selected as the reference voltage to the drive amplifier 1. In this state, the clock pulse K is output from the output capo P2 of the CPU 6.
P is output for a period of τ1 (time 1+). Drive amplifier 1
The clock pulse KP input to the power amplifier 2 is amplified to a predetermined amplitude based on the magnitude of the reference voltage E, and is further amplified to a predetermined amplitude based on the magnitude of the reference voltage E.
The power is amplified by , and the output voltage ■H is applied to the vibrator 3. This voltage V)l is the upper limit applied voltage at which cavity silane does not occur during running, and the magnitude of the reference voltage E is set so that such an output voltage H is output from the power amplifier 2. ing.

Now, based on the measurement results of the water speedometer 4, if the stoppage of the ship is detected, a predetermined switching signal S for switching the switch 7 is output from the output port (Pa). As a result, the switch 7 is switched to the E2 side and E2 is selected as the reference voltage to the drive amplifier 1 (time t2). In this state, the clock pulse KP is output from the output capacitor P2 for a period of τ2. (time t a). The clock pulse KP input to the drive amplifier 1 is amplified to a predetermined amplitude based on the large amplitude of the reference voltage E2, and further power amplified by the power amplifier 2, and an output voltage VL is applied to the vibrator 3. This voltage VL is the upper limit applied voltage value at which cavity silane is not generated when the ship is stopped, and the magnitude of the reference voltage E2 is set so that such an output voltage 1 is outputted from the power amplifier 2.

In this embodiment, the output voltage VL when the ship is stopped is set to 1/2 of the output voltage V)I when the ship is running.

By the way, if the average output capacity of the vibrator 3 is constant between when the ship is running and when the ship is stopped, R is the impedance of the load, τ. If the period of the clock pulse KP is V)I=2VL, then r2=4r, and if the applied voltage is set to 172, the output period can be extended by four borrowers. By lengthening the output period of the transmitted pulse in this way, a distance integration effect can be obtained, and it is possible to prevent a decrease in the transmitted sound pressure and reception sensitivity due to a reduction in the output voltage.

In the above embodiment, when the ship is running and bubbles generated by cavitation are being washed away, a larger signal may be applied to the vibrator 3 by changing the reference voltage E to the drive amplifier 1. It is possible.

Further, in the above embodiment, when the ship is not moving, it is also possible to keep the reference voltage E2 constant and lengthen the period during which the clock pulse KP is sent.

Further, in the above embodiment, the voltage applied to the vibrator 3 is set in two stages depending on whether the boat speed is stopped or running, but it may be set in multiple stages depending on the boat speed when running.

[Effect of the invention 1 According to the present invention, since the voltage applied to the electric-ultrasonic conversion means or the sending period of the clock pulse is changed according to the measured speed of the ship, it is possible to change the voltage applied to the electric-ultrasonic conversion means or the sending period of clock pulses when the ship is running or when the ship is stopped. At times, the occurrence of cavitation can be appropriately prevented, ultrasonic waves can be efficiently transmitted into the water, and the delivery sensitivity can be increased when the ship is running or stopped.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram showing one embodiment of the underwater detection device of the present invention, FIG. 2 is a time chart showing the operation of the device shown in FIG. 1, and FIG. The block diagram, FIG. 4, is a diagram showing the transmitted sound pressure with respect to the voltage applied to the vibrator. DESCRIPTION OF SYMBOLS 1... Drive amplifier, 2... Power amplifier, 3... Vibrator, 4... Water speed meter, 5... Interface,
6...CPU, 7...Switch. Patent Applicant Furuno Electric Co., Ltd. Agent Patent Attorney Seihaku Ao and 1 person Figure 1 Figure 2 Figure 3 Figure 4 Vi V @ $ [h3 to applied voltage n

Claims (3)

[Claims] (1) A clock pulse output means for outputting a clock pulse, an amplification means for amplifying the clock pulse from the clock pulse output means, and an electric-ultrasonic conversion means for converting an output signal from the amplification means into an ultrasonic signal; a water-related ship speed measuring means for measuring the ship's speed relative to water; a means for changing the output voltage from the amplification means according to the ship speed measured by the water-related ship speed measuring means; and a water-related ship speed measuring means. An underwater detection device characterized by comprising: means for changing the output period of the clock pulse sent out by the clock pulse output means according to the measured ship speed. (2) clock pulse output means for outputting clock pulses, amplification means for amplifying the clock pulses from the clock pulse output means, and electric-ultrasonic conversion means for converting the output signal from the amplification means into an ultrasonic signal; It is characterized by comprising a ship speed relative to water measuring means for measuring the speed of the ship relative to water, and a means for changing the output voltage from the amplification means according to the ship speed measured by the ship speed relative to water measuring means. underwater detection device. (3) clock pulse output means for outputting clock pulses, amplification means for amplifying the clock pulses from the clock pulse output means, and electrical-ultrasonic conversion means for converting the output signal from the amplification means into an ultrasonic signal; A ship speed relative to water measuring means for measuring the speed of the ship relative to water, and a means for changing the output period of the clock pulse sent by the clock pulse output means according to the ship speed measured by the ship speed relative to the water measuring means. An underwater detection device characterized by: