CN103231787A - An Ultrasonic Detection Method of Ship's Draft - Google Patents

Abstract

The invention discloses an ultrasonic detection method for ship draft, which comprises the following steps: refitting the detection door; calculating depth error compensation; and (4) angle error compensation calculation. The invention respectively and evenly installs ultrasonic distance sensors facing to the water surface and the water bottom on the upper side and the lower side of the detection door, even if the fluctuation of the detection door is severe, the errors of the detected X and Y are delta respectively₁And delta₂But due to delta₁=-δ₂The ship draft Z is (L- (X + delta)₁)-(Y+δ₂) And (L-X-Y), and the error caused by the up-and-down fluctuation of the detection gate is just repaired. According to the invention, the angle sensor is vertically and upwards arranged on the detection door, when a ship to be detected passes through the upper part of the detection door, the deviation angle theta of the detection door is measured, when the measured value of the draft is Z, the corrected draft S is S-Z cos theta, and the error caused by the left-right shaking of the detection door is overcome through the restoration of the angle error.

Description

An Ultrasonic Detection Method of Ship's Draft

technical field

The invention relates to a detection technology of the draft of a ship, in particular to an ultrasonic detection method of the draft of a ship.

Background technique

Ultrasonic waves with a frequency higher than 20kHz. Ultrasonic waves have very little attenuation in liquids and solids, and have strong penetrating ability. Especially for opaque solids, ultrasonic waves can penetrate tens of meters in thickness, and can obtain relatively concentrated sound energy. It is precisely because of such huge advantages that ultrasonic ranging technology has been widely used in the fields of underwater target detection and positioning recognition.

In order to ensure the safe operation of inland waterway ships and waterways, real-time monitoring and early warning of the ship's draft depth is required underwater. The existing ship draft monitoring system is to measure the vertical height between the water surface and the bottom of the ship. The installation method is shown in Figure 1. The floating bodies at both ends of the sensor array detection door are two ships. The working principle is: set the distance from the detection door to the water surface as H, and the distance measured by the upward sensor as X. Then when the water flow is stable, the draft of the ship to be measured is (H-X), and according to this data, the draft of the ship can be known, and the problems of overloading and super height can be strictly prevented.

The disadvantage of the above method is that the floating bodies used are two ships, and the single-beam ultrasonic sensor array is arranged on a very long steel structure installation door bracket, and the two ends of the bracket are respectively fixed on a floating boat. This can introduce two kinds of measurement errors:

The first type of error: the steel structure bracket itself has a certain degree of flexibility. Due to the influence of water flow fluctuations and gravity inside the channel, the installation door may sink to a certain extent, resulting in distortion of the measured draft.

The second type of error: when the pontoons on both sides are shaking with the current in the water, the height of the two ships is different, which leads to the difference in the height of the installation door, which will also affect the judgment of the navigation status of the ship, and there are certain hidden dangers.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the present invention is to design an ultrasonic detection method for the draft of a ship that can overcome the impact of the up and down fluctuation and left and right shaking of the detection door on the detection accuracy.

In order to achieve the above object, the technical solution of the present invention is as follows: an ultrasonic detection method of the draft of a ship, comprising the following steps:

A. Refit the detection door

Ultrasonic distance sensors facing the water surface and the bottom are evenly installed on the upper and lower sides of the detection door. The upper and lower two are a group, a total of M groups, and each group is on the same vertical line; the ultrasonic angle sensor is installed vertically upward on the detection door;

B. Calculation of depth error compensation

Let the total depth of the river be L, the distance from the ultrasonic sensor facing the water surface to the bottom of the ship is X+δ ₁ , and the distance from the ultrasonic distance sensor facing the bottom to the bottom is Y+δ ₂ , where: X is the distance measured by the ultrasonic distance sensor facing the water surface when the detection door is stable δ ₁ is the error measured by the ultrasonic distance sensor facing the water surface when the detection door fluctuates, Y is the value measured by the ultrasonic distance sensor facing the water bottom when the detection door is stable, δ ₂ is the ultrasonic distance sensor facing the water bottom when the detection door fluctuates The measured error, then the ship's draft Z is

Z=(L-(X+δ ₁ )-(Y+δ ₂ ))

C. Angle error compensation calculation

Assuming that the angle deviation measured by the ultrasonic angle sensor is θ, and the draft measurement value is Z, then the corrected draft S is

S=Z*cosθ.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the present invention, ultrasonic distance sensors facing the water surface and the water bottom are evenly installed on the upper and lower sides of the detection door. Even when the detection door fluctuates violently up and down, the measured errors of X and Y are δ ₁ and δ ₂ respectively, but Since δ ₁ =-δ ₂ , the draft Z of the ship is (L-(X+δ ₁ )-(Y+δ ₂ ))=(LXY), which just corrects the error caused by the up and down fluctuation of the detection door.

2. The present invention installs an angle sensor vertically upward on the detection door. When the ship under test passes above the detection door, the angle θ of the deviation of the detection door is measured, and then the angle error is repaired, which overcomes the error caused by the left and right shaking of the detection door .

Description of drawings

The present invention has 9 accompanying drawings, wherein:

Figure 1 is a schematic diagram of the installation method of the fixed floating sensor above the water surface.

Figure 2 is a schematic diagram of the installation method of the bottom fixed floating sensor.

Figure 3 is a schematic diagram of the detection door sinking.

Figure 4 is a schematic diagram of the detection door floating.

Figure 5 is a schematic diagram of the sinking of the detection door when one sensor is installed at both ends and in the middle facing the bottom of the water.

Fig. 6 is a schematic diagram of the detection door floating up when one sensor is installed at both ends and in the middle facing the bottom of the water.

Fig. 7 is a schematic diagram of the sinking of the detection door when one sensor is installed at both ends facing the water bottom.

Fig. 8 is a schematic diagram of the detection door floating up when one sensor is installed at both ends facing the water bottom.

FIG. 9 is a schematic diagram of angular deviation during ranging.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. The main equipment of the ship draft detection system of the present invention is two detection ships, detection gates and ultrasonic arrays, and the detection ships are used as floating bodies on both sides. The distance from the door to the bottom of the channel is detected at the same time, and an angle sensor is installed to measure the angle deviation of the detection door for error compensation. There are two ways to install the detection door. The first one: the detection door is placed at a suitable position under the water surface by the winch and the cable installed on both sides of the bank. As shown in Figure 1, the detection door may be moved upward or downward by gravity. bending deformation. The second type: the detection door is fixed on the bottom of the water, and both sides are fixed on the lifting frame. The detection door bracket is supported by a floating body. As shown in Figure 2, the detection door may be bent upward or downward under the action of buoyancy and water flow.

For the first error, the compensation method for detecting the error caused by the up and down fluctuations:

Taking the downward bending deformation as an example, the draft of the ship should be (HX), but the water flow in the channel is often relatively turbulent, and the detection door also shakes up and down with the current; when an error of δ occurs, the draft of the ship should be is (H-(X+δ ₁ )). When the ship under test passes above the detection door and the ultrasonic distance sensor performs data measurement, the possible states of the detection door are any of the attitudes shown in Figure 3-8. The installation methods of the ultrasonic distance sensor facing the bottom can be as follows: two groups of ultrasonic distance sensors facing the water surface and the bottom; only one ultrasonic distance sensor facing the bottom is installed in the middle and at both ends; the ultrasonic distance sensor facing the bottom Install only one at each end. When the installation method is shown in Figure 3 and Figure 4, an ultrasonic distance sensor is installed on the upper and lower sides at the same position of the detection door. The ultrasonic distance sensor facing the water bottom measures the distance from the detection door to the water bottom as Y, and when an error exists, the distance from the detection door to the water bottom becomes (Y+δ ₂ ). When the detection door swings upwards, δ ₂ is a positive value; when the detection door swings downwards, δ ₂ is a negative value. And δ ₂ =−δ ₁ . The calculation method of draft Z is:

Z=(L-(X+δ ₁ )-(Y+δ ₂ ))=(LXY) (1)

The present invention just utilizes this error δ to compensate the draft, so (L-X-Y) is the accurate draft, which is closer to the real value.

For the second error, the compensation method for the error caused by the left and right swing of the detection door:

An angle sensor is installed vertically above the detection door. When the ship under test passes above the detection door, the angle deviation measured by the angle sensor is shown in Figure 9. The inclination is θ degrees, and the draft measurement value is Z. Then the corrected The draft S is

S＝Z*cosθ (2)

Through the above calculation, the draft is closer to the real value.

Claims (1)

1. the ultrasonic detection method of a shipping draft is characterized in that: may further comprise the steps:

A, repacking detecting gate

To the water surface and water-bed ultrasonic distance sensor, two is one group up and down at each even attachment face of the both sides up and down of detecting gate, and M organizes altogether, and every group is on the same perpendicular line; The super sonic angular transducer is installed on detecting gate vertically upward;

B, depth error compensation are calculated

If the total depth of river is L, towards the ultrasonic transduter of the water surface apart from hull bottom X+ δ ₁, towards the water-bed Y+ δ of the ultrasonic distance sensor distance at the bottom ₂, wherein: X is value, the δ that detecting gate records towards the ultrasonic distance sensor of the water surface when steady ₁The error that records towards the ultrasonic distance sensor of the water surface when fluctuating for detecting gate, Y is value, the δ that detecting gate records towards the ultrasonic distance sensor at the bottom when steady ₂The error that records towards the ultrasonic distance sensor at the bottom when fluctuating for detecting gate, then shipping draft Z is

Z=(L-(X+δ ₁)-(Y+δ ₂))；

C, angular error compensation are calculated

If the angular deviation that the super sonic angular transducer records is θ, the draft observed reading is Z, and then revised draft S is

S＝Z*cosθ。

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