JP4497971B2 - Ship speed measuring method and apparatus - Google Patents

Description

  The present invention relates to a ship speed measuring method and apparatus for measuring a ship speed against water (velocity) and its direction (inflow angle) when a ship is running.

A conventional ship speed measurement device transmits and receives an ultrasonic pulse of a predetermined width from a navigating ship to the seabed, measures the Doppler frequency of the received signal, and sets an averaging time constant that can be varied according to the ship speed. It is averaged using the measured average value as the ship speed of the ship (for example, refer to Patent Document 1). Hereinafter, this technique is referred to as a first conventional example.
In addition, the conventional ship speed measuring device includes a tubular support projecting from the underwater side surface of the hull with the front end facing forward, and a center line from the stern to the bow at the front end of the support. Some include a plurality of pressure sensors attached with different angles with respect to the surface, and a calculation unit that calculates a lateral flow angle and a flow velocity in the direction based on the pressure detected by the pressure sensor (for example, , See Patent Document 2). Hereinafter, this technique is referred to as a second conventional example.

JP-A-6-347548 (Claims 1, [0007] to [0011], FIGS. 1 and 2) JP-A-8-170968 (Claims 1, [0009] to [0015], FIGS. 1 to 3)

  In the first conventional example described above, the ship speed measuring device is generally attached to the hull after having been inspected for quality. Therefore, the speed of the ship against water measured when this hull speed measuring device is actually attached to the hull (hereinafter referred to as the mounted state) is the boundary layer (near the hull) that develops mainly on the hull surface. In addition to the influence of the friction between the hull and the fluid, the speed of water flow is slow), and due to the influence of sea conditions such as tidal currents, it is possible to measure the precise speed of water Therefore, even if it is adjusted to match the ground speed measured during the trial operation using the differential global positioning system (DGPS), it is impossible to accurately verify the speed of the watercraft. There was a problem. Here, DGPS refers to a technique for improving accuracy by correcting an error in a GPS measurement result using an FM broadcast radio wave transmitted from a reference station whose position is known. The GPS measurement is performed at the reference station, and the difference between the actual position and the position calculated by the GPS is transmitted by radio waves of FM broadcast, thereby correcting the result measured by the signal from the GPS satellite. An error of about 100 m occurs in normal GPS, but the error is reduced to about 5 m by DGPS.

  In the first conventional example, since the ship speed is calculated by receiving reflected waves from an object floating in the water or plankton in the mounted state, a water tank test using a model ship is performed in advance. Even if the vessel speed measurement device is inspected, this tank test will calculate the ship speed by receiving the reflected wave from the bottom of the tank, and it is difficult to accurately verify the ship speed. there were.

  On the other hand, in the above-described second conventional example, the tubular support device projects from the underwater side surface of the hull with the front end facing the front side, so that the tubular support device can be used for other ships, underwater suspended matters, etc. There has been a problem that there is a high risk of damage caused by collision with the pipe or damage caused by the force applied to the tubular support due to waves or sudden movement of the hull.

  The present invention has been made to solve the above-described problems, and its purpose is to measure the speed and direction of the watercraft with high accuracy and to reduce the risk of damage to the sensor. A speed measurement method and an apparatus therefor are obtained.

In order to solve the above-mentioned problem, a ship speed measuring method according to the invention described in claim 1 is substantially the same as the position on the hull centerline below the bow water surface and the hull centerline on the port side and starboard side. A method for measuring the speed of a ship in which a plurality of pressure sensors are arranged at equally spaced positions, the tank test using a model ship having a ship shape similar to the ship, or a theory based on the ship shape of the ship By calculating, for each draft and each inflow angle, the pressure measurement values of the plurality of pressure sensors, the inflow angles, the pressure measurement values, the water speed against water, the water density, and the plurality of characteristic curves relating to the inflow angle are obtained. And a second step of calculating the speed of the water vessel and the inflow angle based on the pressure measurement values of the plurality of pressure sensors in the ship , the measured water density, and the plurality of characteristic curves. Have It is characterized by a door.

According to a second aspect of the present invention, there is provided the ship speed measuring method according to the first aspect, wherein the pressure measurement value of the pressure sensor arranged on the hull outer plate surface substantially on the center line of the hull below the bow water surface is calculated as P _c. P _p and P _s are measured pressure values of the pressure sensors arranged on the hull outer plate surface at approximately equal intervals from the hull center line on the port side and starboard below the bow water surface, respectively, and the density of water is ρ When the ship's speed against water is U, the plurality of characteristic curves are the first characteristic curve relating to the inflow angle of the value (P _p −P _s ) / (P _c −P _s ), and the value It is characterized by comprising a second characteristic curve relating to the inflow angle of (P _c −P _s ) / ρU ² .

  The invention according to claim 3 relates to the ship speed measuring method according to claim 1 or 2, wherein the plurality of pressure sensors change the plurality of characteristic curves substantially linearly with respect to the change in the inflow angle. However, it is arranged on the surface of the hull outer plate below the bow surface so that the gradient becomes large.

According to a fourth aspect of the present invention, there is provided the ship speed measuring method according to any one of the first to third aspects, wherein the position of the hull outer plate surface below the bow water surface on the substantially hull center line, port and a pressure sensor group including a plurality of pressure sensors arranged in a substantially equally spaced a position from starboard the hull center line, of the hull surface under the bow water surface, the alignment direction perpendicular the plurality of pressure sensors A plurality of rows are arranged in the direction of, and the second step is performed for each row, and the third step of averaging the anti-watercraft speed and the inflow angle calculated for each row is provided. It is characterized by.

A fifth aspect of the present invention relates to the ship speed measuring method according to any one of the first to fourth aspects, wherein pressure sensors are arranged at substantially equal intervals from the hull center line of the port and starboard. Instead, the pressure sensors are arranged above and below the hull outer plate surface along the hull centerline below the bow water surface, and the first and second steps are performed with respect to the inflow angle in the vertical direction. By performing, the said ship speed with respect to water and the said inflow angle of an up-down direction are calculated, It is characterized by the above-mentioned.

Further, boat speed measuring apparatus according to the invention of claim 6 wherein the of the hull surface under the bow water of ships is substantially the position of the hull center line, substantially equally spaced from the port and starboard of the hull centerline A plurality of pressure sensors arranged at a position and a water tank test using a model ship having a hull shape similar to the ship or a theoretical calculation based on the hull shape of the ship. pressure measurement value of the pressure sensor and the inflow angle and the pressure measurements and ship's speed relative to the water and a plurality of characteristic curves obtained by regarding the density and the inflow angle of the water, pressure measurement values of the plurality of pressure sensors When, is characterized in that it comprises based on the density of the separately obtained water, and a control unit for calculating the ship's speed relative to the water and the inflow angle.

Further, the invention according to claim 7 relates to the ship speed measuring device according to claim 6, wherein the pressure measurement value of the pressure sensor arranged on the surface of the hull outer plate approximately on the center line of the hull below the bow water surface is P _c. , P _p and P _s are measured pressure values of the pressure sensors arranged on the hull outer plate surface at approximately equal intervals from the hull center line on the port side and starboard side below the bow water surface, and the density of water is ρ. When the ship's speed against water is U, the plurality of characteristic curves are the first characteristic curve relating to the inflow angle of the value (P _p −P _s ) / (P _c −P _s ), and the value ( P _c −P _s ) / ρU ² and the second characteristic curve relating to the inflow angle.

  The invention according to claim 8 relates to the ship speed measuring device according to claim 6 or 7, wherein the plurality of pressure sensors change the plurality of characteristic curves substantially linearly with respect to the change in the inflow angle. However, it is arranged on the surface of the hull outer plate below the bow surface so that the gradient becomes large.

The invention according to claim 9 relates to the ship speed measuring device according to any one of claims 6 to 8, wherein the position of the hull outer plate surface below the bow water surface on the substantially hull center line, port and a pressure sensor group including a plurality of pressure sensors arranged in a substantially equally spaced a position from starboard the hull center line, of the hull surface under the bow water surface, the alignment direction perpendicular the plurality of pressure sensors place plurality of rows in a direction in which the said control unit includes a pressure measurement value of the plurality of pressure sensors, and the density of the water which is separately obtained, based on the plurality of characteristic curves were calculated for each column The speed with respect to the watercraft and the inflow angle are averaged.

A tenth aspect of the present invention relates to the ship speed measuring device according to any of the sixth to ninth aspects , wherein the pressure sensors are arranged at substantially equal intervals from the hull center line of the port and starboard. instead of, along the hull center line under the bow water surface by placing the pressure sensor in the vertical to the ship outside plate surface, and the control unit, the tank tests or theoretical calculation using the above model ship, draft each and every inflow angle, a plurality of characteristic curves obtained by regarding the pressure measurement values of the plurality of pressure sensors and the inflow angle and pressure measurements and ship's speed relative to the water, the pressure measurement of the plurality of pressure sensors and values, based on the density of the separately obtained water, is characterized by calculating the ship's speed relative to the water and the inflow angle.

  As described above, in the present invention, a plurality of pressure sensors are arranged at a position on the hull center line below the bow water surface, on a position on the hull center line, and on a port and starboard at substantially equal intervals from the hull center line. The first step of obtaining a plurality of characteristic curves related to the pressure measurement values of the plurality of pressure sensors and the inflow angle for each draft and for each inflow angle by a tank test or a theoretical calculation using a model ship; and A second step of calculating a watercraft speed and an inflow angle based on pressure measurement values of a plurality of pressure sensors, separately obtained water density, and the plurality of characteristic curves; . Therefore, it is possible to measure the speed and direction of the watercraft with high accuracy, and the risk of damaging the pressure sensor is low.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a ship speed measuring apparatus according to Embodiment 1 of the present invention.
Boat speed measuring apparatus of this embodiment includes a pressure sensor 1 ₁ to 1 _3, a control unit 2, a storage unit 3, a display unit 4, and an operation unit 5. The pressure sensor 1 ₁ to 1 ₃ supplies, for example, external implantable or stainless is made from those electronic such as a piezoelectric element, each pressure measurement P _c, the P _p and P _s to the control unit 2 . Capacity of the pressure sensor ₁ 1 to 1 _3, for example, when the boat speed is 10 m / s (about 20 knots or equivalent), since the stagnation pressure is about 5.1Maq = about 50 kPa, stagnation in equivalent about 100 kPa (1 atm It is sufficient if the boat speed is about 27 knots in terms of pressure. As shown in FIG. 2, the pressure sensor 1 ₁ is bow underwater hull center line disposed hull surface near the position (see a broken line in FIG. 2), the pressure sensor 1 ₂ and 1 ₃ are bow under water respectively Are arranged on the hull outer plate surface which is almost equidistant from the hull center line of the port and starboard. For optimum arrangement position of the pressure sensor 1 ₁ to 1 ₃ will be described later.

  The control unit 2 includes a CPU (Central Processing Unit), a digital signal processor (DSP), a sequencer, and the like. Based on a characteristic curve creation program, a ship speed measurement program, and the like stored in the storage unit 3, the characteristic curve creation is performed. The entire ship speed measuring device is controlled by executing processing, ship speed measuring process, and the like. That is, for example, when the characteristic curve creation program is read out, it is read into the control unit 2 and controls the operation of the control unit 2. When the characteristic curve creating program is started, the control unit 2 executes a characteristic curve creating process described later under the control of the characteristic curve creating program.

  The storage unit 3 includes a semiconductor memory such as a RAM, a ROM, or a flash memory, an FD drive to which an FD (floppy (registered trademark) disk) is mounted, an HD drive to which an HD (hard disk) is mounted, and an MO (optical MO disk drive to which a magnetic disk is mounted, or CD (compact disk) -ROM, CD-R (Recordable), CD-RW (ReWritable), DVD-ROM, DVD-R, DVD-RW, etc. CD / DVD drive. The storage unit 3 stores in advance a characteristic curve creation program to be executed by the control unit 2, a ship speed measurement program, and other various programs, and the control unit 2 performs the above-described characteristic curve creation program and ship speed measurement program. Used for work when executing various other programs. The display unit 4 includes a CRT display, a liquid crystal display (LCD), an electroluminescence (EL) display, a plasma display panel (PDP), or the like. The operation unit 5 includes a keyboard including a numeric keypad, an enter key, or a function key, a pointing device such as a mouse, a touch pad, or a pen device.

Next, the operation of the boat speed measuring apparatus having the above configuration will be described. First, by conducting a tank test in which the ship speed measuring device of this example is mounted on a model ship, a characteristic curve used when the ship speed measuring device of this example is mounted on an actual ship is created. Hereinafter, the creation of the above characteristic curve will be described with reference to the flowchart shown in FIG. When the ship speed measuring device of this example is set to the characteristic curve creation mode, the control unit 2 sets the draft change number n (n is a natural number), which is the number of times to change the draft, and sets the draft change number n. Set 1 to a variable k for counting. Further, the speed V against water input by the inspector operating the operation unit 5 is stored in a predetermined storage area of the storage unit 3 (step SP1). Here, the draft is changed because the pressure measurement values P _c , P _p, and P _s output from the pressure sensors 11 to 13 are affected by the draft change of the ship, so that a characteristic curve for each draft is created. This is necessary. Moreover, the reason why the anti-watercraft speed U is set is that it is necessary when the control unit 2 creates a characteristic curve described later.

Then, in a water tank, towing at a constant speed the bow underwater hull pressure sensor as shown in FIG. 2 to the surface 1 ₁ to 1 ₃ model ship arranged in the optimum position with the oblique Wataru angle To do. The skew angle corresponds to the inflow angle β, and the speed corresponds to the watercraft speed U set in step SP1. Thus, pressure measurement values P _c from the pressure sensor 1 ₁ to 1 _3, since P _p and P _s is supplied, the control section 2 stores in a predetermined storage area of the storage unit 3, the display unit 4 Display (step SP2). Since the characteristic curve to be created is a function of the inflow angle β, as will be described later, the model ship is changed at a constant speed by changing the skew angle, for example, every 5 degrees from -30 degrees to +30 degrees. Towing. Accordingly, the control unit 2, each oblique Wataru angle, i.e., a predetermined storage area of the pressure measurement values P _c, P _p and P _s to the storage unit 3 from the pressure sensor 1 ₁ to 1 ₃ of each inflow angle β And displayed on the display unit 4.

The pressure measurement P _c of each inflow angle β from the pressure sensor 1 ₁ to 1 _3, the P _p and P _s is supplied all, the control unit 2, the inflow angle β from a predetermined storage area of the storage unit 3 The pressure measurement values P _c , P _p and P _s for each and the speed V of the watercraft are read out, and the values (P _p −P _s ) / (P _c −P _s ) and values (P _c− P _s ) / ρU ² is calculated and then stored in a predetermined storage area of the storage unit 3 and displayed on the display unit 4 (step SP3). ρ is the density of water filled in the aquarium. The value (P _p −P _s ) / (P _c −P _s ) is a parameter for calculating the actual inflow angle β of the actual ship on which the ship speed measuring device of this example is mounted. For example, the value P _p > P _s for the flow from the starboard and (P _p −P _s )> 0, whereas P _p <P _s for the flow from the starboard (P _p− P _s ) <0. Further, the value (P _c −P _s ) / ρU ² is a parameter for calculating the actual water speed U of the actual ship on which the ship speed measuring device of this example is mounted. Note that the value (P _p −P _s ) / (P _c −P _s ) and the value (P _c −P _s ) / ρU ² are both dimensionless. In the case of similar shapes having different sizes but the same shape, the same value can be used.

Next, the control unit 2 creates a first characteristic curve of the inflow angle β and the value (P _p −P _s ) / (P _c −P _s ), and then stores it in a predetermined storage area of the storage unit 3. At the same time, it is displayed on the display unit 4 (step SP4). That is, the control unit 2 reads the inflow angle β and the corresponding value (P _p −P _s ) / (P _c −P _s ) from a predetermined storage area of the storage unit 3, and the inflow angle is plotted on the horizontal axis of the graph. A first characteristic curve indicated by a curve a in FIG. 4 is created by placing β and placing the value (P _p −P _s ) / (P _c −P _s ) on the vertical axis and connecting the points. Next, the control unit 2 creates a second characteristic curve of the inflow angle β and the value (P _c −P _s ) / ρU ^2, and then stores the second characteristic curve in a predetermined storage area of the storage unit 3 and the display unit 4. (Step SP5). That is, the control unit 2 reads the inflow angle β and the corresponding value (P _c −P _s ) / ρU ² from a predetermined storage area of the storage unit 3, A value (P _c −P _s ) / ρU ² is placed on and connected to create a second characteristic curve indicated by a curve b in FIG.

  Next, after incrementing the variable k by 1 (step SP6), the control unit 2 determines whether the variable k is greater than the draft change number n. If the determination result is “NO”, the control unit 2 returns to Step SP2 and repeats the processing of Steps SP2 to SP6 described above. And if the variable k becomes larger than the draft change number n, the judgment result of step SP7 will be "YES", and the control part 2 will complete | finish a series of processes. By repeating the processing of steps SP2 to SP5 described above n times, a first characteristic curve and a second characteristic curve for each draft are created, and each is stored in a predetermined storage area of the storage unit 3, It is displayed on the display unit 4. Note that the first characteristic curve and the second characteristic curve can be expressed by mathematical formulas by applying them to polynomials.

  Here, the basis for creating the first characteristic curve and the second characteristic curve will be described. When an object with a blunt shape, such as a sphere, is placed in a flow of water or the like, the pressure is greatest at a point directly in front of the flow of water or the like, and the pressure drops rapidly as the point moves away from the point. It is known to go. The relationship between the flow of water and the pressure applied to the object can be expressed theoretically in the case of an object with a structurally simple shape such as a sphere, but it can be represented by a general shape such as the shape of a bow. This object cannot theoretically be expressed by mathematical formulas. Therefore, it is necessary to investigate what characteristic curve tendency the relationship between the flow of water or the like and the pressure applied to the object shows by using an experiment or a numerical analysis method. The first characteristic curve and the second characteristic curve tend to change greatly and monotonously even with a slight change in the inflow angle β (for example, change almost linearly with respect to the change in the inflow angle β and have a large gradient). ) Is desirable.

  The quality of the characteristic curve tends to affect the accuracy of the inflow angle β and water speed U measured on the actual ship. It is necessary to keep. As for the optimal arrangement of the pressure sensor, as described above, it is desirable that the tendency of the first characteristic curve and the second characteristic curve changes substantially linearly with respect to the change of the inflow angle β, and the gradient thereof is large. For example, it is desirable to search for such a position by a prior calculation using the Hess & Smith method, and a position where the position is satisfied is an optimum arrangement position. Since the optimal placement position of the pressure sensor differs depending on the shape of the ship, as a general numerical value, the depth of the left and right placement positions cannot be limited to how many meters away from the hull center line. . In addition, even if the distance is long, the characteristic curves tend not to be good if they are arranged in parallel, so each pressure sensor should be arranged so that the normals of the arrangement positions of the pressure sensors intersect at as large an angle as possible. It is better to place it. Here, the Hess-Smith method (Hess & Smith) is a flow distribution that is one of the hydrodynamic singularities in fluid mechanics when an object is present in a flow. This is a method for analyzing the flow by obtaining the strength by numerical analysis.

Next, the measurement of the water speed U and the inflow angle β when the ship speed measuring device of this example is mounted on an actual ship will be described with reference to the flowchart shown in FIG. As the bow underwater hull surface of the pressure sensor 1 ₁ to 1 ₃ as shown in FIG. 2 cruising make at sea like the actual ship arranged in the optimum position. Thus, pressure measurement values P _c from the pressure sensor 1 ₁ to 1 _3, since P _p and P _s is supplied, the control section 2 stores in a predetermined storage area of the storage unit 3, the display unit 4 indicate. Further, the control unit 2 is supplied with the seawater density ρ measured by a density meter (not shown) and stores it in a predetermined storage area of the storage unit 3 and displays it on the display unit 4 installed in the bridge, for example ( Step SP11). The seawater density ρ may be a value converted from the measured water temperature or salt water concentration, or may be input by operating the operation unit 5 by the inspector.

Next, the control unit 2 reads the pressure measurement values P _c , P _p and P _s from the predetermined storage area of the storage unit 3 and calculates the value (P _p −P _s ) / (P _c −P _s ). Thereafter, it is stored in a predetermined storage area of the storage unit 3 (step SP12). Next, the control unit 2 reads the value (P _p −P _s ) / (P _c −P _s ) and the first characteristic curve from the predetermined storage area of the storage unit 3, and as shown in FIG. After obtaining the inflow angle β in the first characteristic curve when taking the value (P _p −P _s ) / (P _c −P _s ), the inflow angle β is stored in a predetermined storage area of the storage unit 3 and displayed on the display unit 4. Display (step SP13).

Next, the control unit 2 reads the value β and the second characteristic curve from a predetermined storage area of the storage unit 3, and as shown in FIG. 4, the value (P _c− P _s ) / ρU ² (this value is assumed to be A) and then stored in a predetermined storage area of the storage unit 3 (step SP14). Since the value (P _c −P _s ) / ρU ² is equal to the value A, Expression (1) is established. Next, the control unit 2 reads the pressure measurement values P _c and P _s and the seawater density ρ from the predetermined storage area of the storage unit 3 and substitutes the equation (1) into the modified equation (2). After calculating the ship speed U against water, a series of processing is terminated (step SP15).
(P _c −P _s ) / ρU ² = A (1)
U = {ρA / (P _c −P _s )} ^1/2 (2)

Thus, in this embodiment, substantially the hull center line disposed hull surface, port and starboard hull bow underwater Each pressure sensor 1 ₂ and 1 ₃ under bow water pressure sensor 1 ₁ When placed on the surface of the hull skin that is approximately equidistant from the center line, the first characteristic curve and the second characteristic curve are obtained in advance by a tank test using a model, and when mounted on an actual ship, the pressure sensor 1 ₁ a pressure measurement value P _c, P _p and P _s from to 1 _3, a sea water density ρ from density meter, based on the first characteristic curve and the second characteristic curve, when the ship is sailing The ship's speed U and the inflow angle β are calculated. Since the first characteristic curve and the second characteristic curve can be created with high accuracy by a tank test using a model ship, the water speed U and the inflow angle β of the actual ship based on this can be calculated with high accuracy. it can.

Further, in this embodiment, unlike the first conventional example described above, it is not necessary to adjust to match the ground speed measured during the trial operation using DGPS. Can do. Further, in this embodiment, the pressure measurement surface of the pressure sensor 1 ₁ to 1 ₃ are arranged flush with the hull surface, the pressure sensor 1 ₁ to 1 ₃ as in the second conventional example described above is There is very little risk of damage.

Embodiment 2. FIG.
In Embodiment 1 mentioned above, the example which calculates | requires the 1st characteristic curve and the 2nd characteristic curve by the water tank test using a model was shown, but this invention is not limited to this. For example, the first characteristic curve and the second characteristic curve may be obtained by theoretical calculation using a numerical analysis method. Examples of the numerical analysis method include the above-mentioned Hess & Smith method based on the potential flow theory and a computational fluid dynamics (CFD) simulation for numerically solving a flow equation of motion.

Embodiment 3 FIG.
In the first embodiment described above, an example of placing three pressure sensors 1 ₁ to 1 ₃ in hull surface under the bow water, the invention is not limited thereto. For example, four, five, or six or more pressure sensors may be arranged on the hull outer plate surface below the bow surface. For example, three pressure sensors 1 ₁ to 1 ₃ as well as arranged shown in FIG. 2, one by one in a predetermined distance apart hull surface of the pressure sensor 1 ₁ to 1 ₃ of that of the lower, overall 6 pressure sensors are arranged. In the case of this example, the water speed U and the inflow angle β obtained by applying exactly the same method as the ship speed measuring method described in the first embodiment to the two rows of pressure sensors are averaged. Therefore, highly accurate measurement can be performed. When the pressure sensors are arranged in a plurality of rows as described above, a stagnation point exists around the pressure sensor having the largest pressure measurement value. In general, when the inflow angle β when the ship is sailing is large, the measurement accuracy is considered to decrease. Therefore, using the pressure measurement value from the row of pressure sensors closest to the stagnation point, the speed V and the inflow angle against the water Calculation of β leads to maintenance of measurement accuracy.

Embodiment 4 FIG.
In Embodiment 1 described above, an example in which a characteristic curve is created by towing a model ship at a constant speed by changing the skew angle from -30 degrees to +30 degrees every 5 degrees for n drafts. Although shown, the present invention is not limited to this. For example, the characteristic curve may be created by increasing the draft change number n or setting the changing skew angle to a smaller angle. In this way, by increasing the number of characteristic curves and taking the average values of the anti-watercraft speed U and the inflow angle β calculated based on them, and using a more precise characteristic curve, the analysis accuracy can be improved. Can do.

Embodiment 5 FIG.
In the first embodiment described above, an example of placing in the horizontal direction three pressure sensors 1 ₁ to 1 ₃ in hull surface under the bow water, the invention is not limited thereto. For example, to place one above the hull surface along the pressure sensor 1 ₁ to 1 ₃ to the hull center line under the bow water. In this case, the pressure measurement value of the pressure sensor disposed in the upper and the pressure measurement P _t, a pressure measurement value of the pressure sensor disposed in the central portion and the pressure measurement P _c, the pressure measurement value of the pressure sensor disposed in the lower portion When the pressure measured value P _b, and in the first embodiment described above, the pressure measured value P _c of the pressure sensor 1 ₁ to the pressure measurement value P _c of the pressure sensor disposed in the central portion, the pressure of the pressure sensor 1 ₂ the measured value P _p in the pressure measurement P _t of the pressure sensor disposed in the upper, the pressure measurement P _s of the pressure sensor 1 ₃ with read as pressure measurements P _b of the pressure sensor disposed in the lower, inflow angle By replacing β with the inflow angle in the vertical direction, the speed of the watercraft and the inflow angle in the vertical direction can be calculated. Incidentally, obtained for ship's speed relative to the water in the above method, the pressure measurement value P _t of the pressure sensor disposed in the upper near the water surface, the pressure measurement value P _b of the pressure sensor disposed far below the water surface There is an asymmetric relationship between them, and it is difficult to say that the values are highly accurate. Accordingly, pairs respect to ship's speed relative to the water pressure measured value P _c from the pressure sensor 1 ₁ to 1 _3, it is better calculated based on P _p and P _s good. However, the relationship between the hull motion measured separately and the incident wave can be grasped by calculating the speed of the watercraft in the vertical direction. In addition, by grasping the hull motion and the water velocity in the vertical direction at the bow, it is possible to estimate the wave height from the phase difference between the incident wave and the hull motion and the flow velocity of the wave itself.

The embodiment has been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment, and there are design changes and the like without departing from the scope of the invention. Are also included in the present invention.
In addition, each of the above-described embodiments can divert each other's technology as long as there is no particular contradiction or problem in its purpose and configuration.

It is a block diagram which shows the structure of the ship speed measuring apparatus which is Embodiment 1 of this invention. It is a conceptual diagram which shows an example of arrangement | positioning of a pressure sensor. It is a flowchart for demonstrating the characteristic curve creation process of a control part. It is a figure which shows an example of a characteristic curve. It is a flowchart for demonstrating the ship speed measurement process of a control part.

Explanation of symbols

1 ₁ to 1 ₃ pressure sensor, 2 control unit, 3 storage unit, 4 display unit, 5 operation unit.

Claims (10)

A ship speed measurement method in which a plurality of pressure sensors are arranged at a position on the hull center line on the hull outer plate surface below the bow water surface and at a position that is substantially equidistant from the hull center line on the port side and starboard side. There,
Theoretical calculations based on the hull shape of the tank test or the marine vessel using a model ship having a hull shape similar to the ship, each draft each and inflow angle, the pressure measurement values of the plurality of pressure sensors inflow angle and A first step of determining a plurality of characteristic curves related to the pressure measurement value, the speed of water vessel, the density of water, and the inflow angle ;
A second step of calculating a watercraft speed and an inflow angle based on pressure measurement values of a plurality of pressure sensors in the ship , measured water densities, and the plurality of characteristic curves; A ship speed measuring method characterized by the above. The pressure measurement value of the pressure sensor arranged on the surface of the hull outer plate approximately on the hull center line below the bow water surface is P _c, and the hull that is substantially equidistant from the hull center line on the port side and starboard below the bow water surface. When the pressure measurement values of the pressure sensor arranged on the outer plate surface are P _p and P _s respectively, the water density is ρ, and the ship's speed against water is U, the plurality of characteristic curves are values From the first characteristic curve relating to the inflow angle of (P _p −P _s ) / (P _c −P _s ) and the second characteristic curve relating to the inflow angle of value (P _c −P _s ) / ρU ² The ship speed measuring method according to claim 1, wherein   The plurality of pressure sensors are arranged on a surface of the hull outer plate below the bow surface so that the plurality of characteristic curves change substantially linearly with respect to the change in the inflow angle and the gradient thereof increases. The ship speed measuring method according to claim 1 or 2, characterized in that. A pressure sensor group comprising a plurality of pressure sensors disposed at a position on the hull center line on the hull outer plate surface below the bow water surface and at a position substantially equidistant from the hull center line on the port side and starboard side; the bow underwater hull surface, said plurality of multiple columns arranged in the arrangement direction and a direction perpendicular to the pressure sensor, performs the second step in each row,
The ship speed measuring method according to any one of claims 1 to 3, further comprising a third step of averaging the ship speed against water and the inflow angle calculated for each row. Instead of placing a pressure sensor at substantially equal intervals and a position from the hull center line of the port and the starboard, the pressure sensor vertically on the hull surface along said centreline under the bow water The first and second steps are arranged and the first step and the second step are performed on the inflow angle in the vertical direction, thereby calculating the speed of the watercraft and the inflow angle in the vertical direction. 4. The ship speed measuring method according to any one of 4 above. A plurality of pressure sensors arranged at a position on the hull center line of the hull outer plate surface below the bow water surface of the ship and at a position that is substantially equidistant from the hull center line on the port and starboard;
Theoretical calculations based on the hull shape of the tank test or the marine vessel using a model ship having a hull shape similar to the ship, each draft each and inflow angle, the pressure measurement values of the plurality of pressure sensors inflow angle and based on a plurality of characteristic curves obtained by regarding the density and the inflow angle of the pressure measurements and ship's speed relative to the water and water, and the pressure measurement values of the plurality of pressure sensors, and density of the separately obtained aqueous And a controller for calculating the speed of the water vessel and the inflow angle. _Pc is a pressure measurement value of a pressure sensor disposed on the hull outer plate surface on the hull center line substantially below the bow water surface, and the outer hull is approximately equidistant from the hull center line on the port side and starboard below the bow water surface. When the pressure measurement values of the pressure sensors arranged on the plate surface are P _p and P _s respectively, the density of water is ρ, and the ship's speed against water is U, the plurality of characteristic curves are values ( P _p −P _s ) / (P _c −P _s ) of the first characteristic curve related to the inflow angle and a value (P _c −P _s ) / ρU ² of the second characteristic curve related to the inflow angle. The ship speed measuring device according to claim 6.   The plurality of pressure sensors are arranged on a surface of the hull outer plate below the bow surface so that the plurality of characteristic curves change substantially linearly with respect to the change in the inflow angle and the gradient thereof increases. The ship speed measuring device according to claim 6 or 7. A pressure sensor group comprising a plurality of pressure sensors disposed at a position on the hull center line on the hull outer plate surface below the bow water surface and at a position substantially equidistant from the hull center line on the port side and starboard side; the bow underwater hull surface, and a plurality of rows arranged in a direction in which the alignment direction perpendicular the plurality of pressure sensors,
Wherein the control unit includes a pressure measurement value of the plurality of pressure sensors, and the density of the water which is separately obtained, on the basis of said plurality of characteristic curves, the ship's speed relative to the water and the inflow angle was calculated for each column The ship speed measuring device according to any one of claims 6 to 8, wherein each of the values is averaged. Instead of placing a pressure sensor at substantially equal intervals and a position from the hull center line of the port and the starboard, the pressure sensor vertically on the hull surface along said centreline under the bow water Place and
Wherein the control unit, the tank tests or the theoretical calculations using the model ship, each draft each and inflow angle, pressure measurement values of the plurality of pressure sensors and the inflow angle and the pressure measurements in the vertical direction to water a plurality of characteristic curves obtained by regarding the boat speed and the inflow angle of the vertical direction, and the pressure measurement values of the plurality of pressure sensors, based on the density of the separately obtained water, ship's speed relative to the water and the The ship speed measuring device according to any one of claims 6 to 9, wherein an inflow angle in a vertical direction is calculated.

Images