JPH0350089A - Hydrofoil depth automatic control device for hydrofoil craft - Google Patents

Abstract

PURPOSE:To perform real-time control to keep the hydrofoil depth at a bow approximately constant even at the time of stormy weather by providing a wave height detecting means, a spectrum analysis arithmetic means, a wave-of- encounter predictive arithmetic means and a flap control signal generating means. CONSTITUTION:In a hydrofoil depth automatic control device FDC, to which a wave height signal from a bow height detector 50, is inputted an arithmetic unit 90 performs real-time spectrum analysis to compute/output the frequency, amplitude and phase of each wave, and on the basis of these time series signals, a wave-of-encounter predictive arithmetic unit 91 computes predictively the wave height of waves-of-encounter met by a front strut in the near future after the set time from the present time. A flap control signal generating means 92 outputs a flap control signal proportional to the height of the waves-of- encounter to a forward flap driving means 80 so as to suppress the fluctuation of the hydrofoil depth of a front hydrofoil. The real-time control is thus performed to keep the hydrofoil depth at the front part approximately constant even at the time of stormy weather.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic blade depth control device for a hydrofoil boat, and particularly in stormy weather, predicts waves that the front strut will encounter in the near future and adjusts the front flap. This relates to automatic control of blade depth through

[Prior art]

Recently, a high-speed hydrofoil boat as described in Japanese Patent Publication No. 53-37636 has been put into practical use. The front wing is equipped with a front flap and the rear wing is equipped with a rear flap.The stern section is equipped with a water jet type propulsion device, and the stern section is equipped with a water jet type propulsion device, which can be detected by various detection devices. Based on the signal, the control device controls the front flap drive, the rear flap drive and the rudder (
front struts).

When the above-mentioned hydrofoil boat runs on its wings, when the changes in the sea surface are relatively gentle and the wavelength of the waves is large, the response delay of the flap drive device (about 50 seconds) and the response delay of the vertical movement of the hull do not pose much of a problem. If the control device is set to the contour mode, the front flap is automatically controlled by the control device so that the set blade depth is set by the blade depth setting lever. However, since the vessel is sailing at a high speed of 45 knots, the wavelength of the encountering waves becomes smaller in rough seas during rough weather, so the response delay described above becomes a problem.

That is, in rough seas under rough weather, if only the front flap and the rear flap are automatically controlled by the control device, phenomena such as the wing breaking the water surface or the top of the encountering wave colliding with the bottom of the bow section will occur.

Therefore, in the past, in order to enhance the weather resistance performance in stormy weather, the pilot operated the blade depth setting lever by identifying the peaks or troughs of the encountering waves approximately 20 to 30 meters ahead and the size of the wave height. The front flap was controlled downwards during wave crests and upwards during troughs, depending on the wave height.

[Problem to be solved by the invention]

As mentioned above, during rough weather, it not only takes a lot of effort to constantly stare at the encountering waves about 20 to 30 meters in front of you, judge the wave situation, and delicately operate the wing depth setting lever.
There is a problem in that only a sufficiently skilled operator can operate it.

Moreover, there is a problem in that even a skilled operator may sometimes make mistakes in judgment, resulting in failure to obtain sufficient weather resistance.

An object of the present invention is to provide a deep-depth automatic control device for a hydrofoil ship that can automatically control the wing depth by predicting encounter waves that the front strut will encounter in the near future and controlling the front flap. That's true.

[Means to solve the problem]

The deep-depth automatic control device for a hydrofoil boat according to the present invention includes a front wing and a rear wing provided at the bow and a stern, respectively, a front flap provided at the front wing, and a rear wing provided at the rear wing. In a hydrofoil boat equipped with a flap, a front flap drive means for driving the front flap, and a rear flap drive means for driving the rear flap, a wave height detection means for detecting a distance from a predetermined part of the bow section to a wave surface; , Spectrum analysis that receives the wave height signal from the wave height detection means, performs spectrum analysis in real time on the time-series wave height signal during the latest past predetermined time, calculates and outputs the frequency, amplitude, and phase of each wave. A calculation means receives the output from the spectrum analysis calculation means in real time, and uses the frequency, amplitude, and phase of a time series of waves with a frequency lower than a predetermined high frequency to calculate the output from the present to the near future after a set time. an encountering wave prediction calculation means for predicting and calculating the wave height of the encountering waves encountered by the front strut; and a signal regarding the encountering wave height from the encountering wave prediction calculation means is received in real time to calculate changes in the blade depth of the front wing. It is provided with a flap control signal generating means for generating a flap control signal proportional to the height of the encountered wave so as to suppress the wave height, and outputting the generated flap control signal to the front flap driving means.

[Effect]

In the deep automatic control device for a hydrofoil boat according to the present invention, the spectrum analysis calculation means receives the wave height signal from the wave height detection means, and calculates the spectrum in real time for the time-series wave height signal during the latest past predetermined time. It analyzes and calculates and outputs the frequency, amplitude, and phase of each wave. The encountering wave prediction calculation means receives the signal regarding the time series wave frequency, amplitude, and phase obtained by the spectrum analysis, and calculates the current wave frequency, amplitude, and phase using the frequency, amplitude, and phase of the wave having a lower frequency than a predetermined high frequency. The wave height of the encountering wave that the front strut will encounter in the near future after a set time is calculated and predicted. Note that the set time is determined as, for example, the sum of the response delay time of the front flap drive system and the number of hours for response to vertical movement of the hull.

The flap control signal generating means receives a signal regarding the encountering wave height from the encountering wave prediction calculation means in real time, and generates a flap control signal proportional to the encountering wave height so as to suppress fluctuations in the blade depth of the front wing. generated and output to the front flap drive means.

As a result, when the front strut encounters the encounter wave after the set time, the front flap has already been controlled by the flap control signal and the hull has started responding in the vertical direction.
Fluctuations in the blade depth of the forebody are automatically suppressed without response delay. Since the above-mentioned automatic deep-depth control is executed moment by moment in real time, constant fluctuations in blade depth are suppressed, dramatically improving the weather resistance of hydrofoils, and burdening the operator with all the heat. It doesn't cost anything.

〔Effect of the invention〕

According to the deep automatic control device for a hydrofoil boat according to the present invention,
As explained in the above [Function] section, by providing the wave height detection means, the spectrum analysis calculation means, the encountering wave prediction calculation means, and the flap control signal generation means, the hydrofoil boat can avoid rough waves when winging. It is possible to automatically control the front wing depth in real time so that it remains approximately constant even under the weather, thereby improving weather resistance and relieving the burden on the operator. Effects can be obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

This embodiment is an example in which the present invention is applied to a hydrofoil boat commonly called a jet foil.

As shown in Figures 1 and 2, the hull 10 of the hydrofoil JF
A front strut 12, which also serves as a rudder with an airfoil cross section, is provided at the center of the lower part of the bow of the ship, and its upper end is rotatable around a vertical axis and a horizontal axis in the left-right direction.The lower end of the front strut 12 is An anterior mass 13 is provided, the anterior mass 13
A front flap 14 is provided at the rear edge. During wing running, the front strut 12 is extended vertically downward as shown, and during boat running, it is rotated in the direction of arrow 11 and raised horizontally forward.

A pair of left and right rear struts 20 and 22 each having an airfoil cross section are rotatably provided at the lower part of the stern part of the hull 1O at their upper ends via horizontal pivot pins 21 in the left and right direction. At an intermediate position between 20 and 22, an intermediate strut 23 is rotatably provided at its upper end via a horizontal pivot pin in the left and right direction, and extends between the upper ends of the port rear strut 20 and the starboard rear strut 22. Quality 2
4 is provided, and the rear M24 is also fixed to the lower end of the intermediate strut 23. At the rear edge of the rear flap 24, there are four rear flaps 26 to 2, two on the port side and two on the starboard side.
9 is provided. However, in normal cases, the inner rear flaps 26 and 2 and the outer rear flaps 27 and 29 of each side are operated synchronously.

A water jet type propulsion device (path shown) is provided over the intermediate strut 23 and the bottom of the hull near its upper end. However, it is also possible to provide a propeller type propulsion device instead. When the boat is running, the rear struts 20 and 22 and the intermediate strut 23 are extended vertically downward as shown in the figure, and when the boat is running, they are rotated in the direction of arrow 25 and raised horizontally rearward.

As shown in FIGS. 2 and 4, hydraulic actuators rotate the front flap 14, the port inner rear flap 26, the port outer rear flap 27, the starboard inner rear flap 28, and the starboard outer rear flap 29, respectively. 30.32~
34, and a hydraulic actuator 31 for rotationally driving the front strut 12 about a vertical axis, and a hydraulic actuator 31 for rotating the front strut 12 forward about a horizontal axis, and a rear Strut 20・
A hydraulic actuator for rotationally driving the shafts 22 and 23 around the pivot shaft 21 is also provided. However, it is also possible to provide electric actuators in place of the hydraulic actuators 30 to 35 and the like.

Next, a description will be given of the hull motion during wing running, in which the hull 1O is floated above the water surface by the lifting force of the front mass 13 and the rear mass 24, with reference to FIG. During wing running, the hull 10 floats above the water surface, but the front and rear wings 13 and 24 and the front and rear struts 12, 20, 22, and 23 are affected by waves, so the hull 10 is suspended vertically. Heaving around the roll axis 40 and rolling around the pitch axis 4
1 and yawing about the yaw axis 42. During wing running, the front struts 12 and rear struts 20, 22, and 23 act to suppress rolling and increase the directional stability of wing running. On the other hand, the front wing 13, the front flap 14, the rear part 824, and the rear flaps 26 to 29 act to suppress pitching.

Here, when the front flap 14 is tilted downward, the front wing 13
When the front flap 14 is tilted upward, the lift force of the front flap 14 increases, causing the bow side to move upward, and conversely, when the front flap 14 is tilted upward, the bow side moves downward. This also applies to the rear flaps 26 to 29, and the front flap 14 and rear flaps 26 to 29
By tilting them in the same direction, the altitude of the hull 10 relative to the water surface (that is, the depth of the wing) can be changed. however,
In fact, the height of the hull 10 relative to the water surface is adjusted only via the front flap 14. In addition, the pitch angle (that is, trim) can be controlled via the front flap 14 and the rear flaps 26 to 29, and the front flap 14 and the rear flaps 26 to 29 can be reversed in synchronization with pitching. Pitching can be suppressed by tilting the rear flap 26 on the port side.
・Turn smoothly in the roll direction by rotating the front strut 12 (rudder) around the vertical axis while giving a roll angle by tilting the rear flap 27 and the starboard rear flaps 28 and 29 in opposite directions. Rolling can be suppressed by tilting the port side rear flaps 26 and 27 and the starboard side rear flaps 28 and 29 in opposite directions in synchronization with the rolling.

Next, the attitude control of the hull 10 (altitude, wing depth, pitch angle,
Detectors and the like for obtaining various detection signals necessary for pitching, rolling, etc.) and pitching/rolling suppression control will be explained.

As shown in FIG. 2, the bow section includes a pair of ultrasonic bow altitude detectors 50 that detect the distance to the water surface, and a bow lateral accelerometer 51 that detects the horizontal horizontal acceleration of the bow.
Bow vertical accelerometer 52 that detects vertical acceleration of the bow
is provided.

A port vertical accelerometer 53 and a starboard vertical accelerometer 54 for detecting acceleration in the vertical direction are provided on the port and starboard sides of the stern, respectively. In the wheelhouse, there are a pitch gyro 55 that detects pitch angle and a roll gyro 5 that detects roll angle.
6, and a yaw rate gyro 5 that detects the speed of yaw movement.
7 is provided. A ship speed meter for detecting ship speed is provided near the lower end of the front strut 12.

The wheelhouse includes a control unit CU that receives detection signals from the various detection devices described above, and a steering wheel 6 that commands turning.
0 and the depth of the wings 13 and 24 via the front flap 14 (
Depth setting lever 6 for setting the height of the hull relative to the water surface
1, a throttle lever (shown in the figure) for operating the throttle valve of the gas turbine engine that drives the propulsion device, and various other switches and instruments.

Next, an overview of the control system of the hydrofoil JF will be explained.

As shown in the block diagram of the control system in FIG. 4, the signal HD from the bow altitude detector 50 and the signal HC from the depth setting lever 61 are output to the depth error amplifier 64, and the difference between both signals (HC- A control signal ΔHA which is amplified from the signal HD) is output to the front flap servo amplifier 80.
A drive signal is output from 0 to the front flap actuator 30.

The steering signal WC from the steering wheel 60 (or the steering signal from the course keeping circuit (as shown)) and the signal RD from the roll gyro 56 are supplied to the roll differential amplifier 66, and the difference between the two signals (
A control signal ΔRA obtained by amplifying the rate of change of WC-RD is output to the port flap servo amplifiers 82 and 83, and a signal obtained by inverting the control signal ΔRA by an inverter 69 is output from the starboard flap servo amplifiers 84 and 85. Drive signals are supplied from the port side flap servo amplifiers 82 and 83 to the flap actuators 32 and 33, respectively. Therefore,
When transitioning to turning navigation and during turning navigation, the hull 1 is rotated to the inside of the turn so that the roll angle is as commanded by the steering signal WC.
The port side rear flaps 26 and 27 and the starboard side rear flaps 28 and 29 are driven in mutually opposite directions so that the 0 rolls. At the same time, the signal RD from the roll gyro 56
is amplified into a control signal RDA by the amplifier 74 and supplied to the rudder servo amplifier 81, and the servo amplifier 81 outputs a drive signal to the front strut turning actuator 31. Therefore, the hull lO rolls in the turning direction in accordance with the steering signal from the steering wheel 60, and the front strut 12 is driven to turn in the turning direction in accordance with the roll angle. Therefore, the hull lO turns smoothly and only a small inertial force acts on the passengers and crew.

During the above turning, a signal YD from the yaw rate gyro 57 that is proportional to the turning speed around the yaw axis 42 is amplified by the amplifier 75 into a control signal YDA and output to the rudder servo amplifier 81.
The rotation speed of the is controlled. Similarly, the signal LD from the bow lateral accelerometer 51 is converted into the control signal LD by the amplifier 70.
A is amplified and supplied to the rudder servo amplifier 81, where it is used to limit the lateral acceleration of the bow section during turning.

Next, the effect of suppressing pitching and rolling will be explained.

The signal VD from the bow vertical acceleration needle 52 is supplied to the integrating amplifier 68, and the signal RRD obtained by squaring the roll angle detected by the roll gyro 56 is supplied from the roll square circuit 67 to the integrating amplifier 6. A control signal VRA obtained by combining and integrally amplifying the signals VD and RRD is supplied to the front flap servo amplifier 80. That is, although the vertical acceleration of the bow increases in accordance with the pitching of the hull 10, the servo amplifier 8 outputs a control signal VRA that cancels out the pitching.
0 to control the front flap 14. Furthermore,
By supplying the signal RRD to the integrating amplifier 68, the signal VD is corrected by the vertical acceleration variation caused by the roll angle during turning or rolling.

The signal PD from the pitch gyro 55 is supplied to the pitch differential amplifier 65, and the control signal ΔPA, which amplifies the pitch angle change rate, is supplied to the port and starboard flap servo amplifiers 82 to 8.
5, and the control signal ΔPA is inverted by an inverter 62 and supplied to a front flap servo amplifier 80. As a result, when the bow side moves upward due to pitching, control is performed to tilt the front flap 14 upward to lower the bow and tilt the rear flaps 26 to 29 downward to raise the stern, thereby suppressing pitching. Ru.

When the hull 10 rolls, the port rear flaps 26 and 27 and the starboard rear flaps 28 and 29 are driven in mutually opposite directions and in a direction that suppresses rolling via a control signal ΔRA corresponding to the rate of change of the roll angle. rolling is suppressed.

On the other hand, the signal LVD from the port vertical accelerometer 53 is amplified by the amplifier 71 to the control signal LVA and supplied to the port flap servo amplifiers 82 and 83, and the signal RVD from the starboard vertical accelerometer 54 is amplified by the amplifier 73 to the control signal RVA.
Amplified by VA and starboard flap servo amplifier 84/85
supplied to

In this way, for example, when rolling to the port side, the port rear flaps 26, 27 are tilted downward and the starboard rear flaps 28, 29 are tilted upward, thereby suppressing rolling. The control unit CU in Figure 4 actually includes a computer, multiple A/D converters, amplifiers, and multiple D
/A converter etc.

Next, with reference to FIGS. 5 to 8, the configuration and operation of the deep automatic control device FDC incorporated into the control system of the hydrofoil boat will be explained.

This deep-depth automatic control device FDC analyzes past wave height data encountered by the bow, predicts the near future wave height of encountered waves by the response delay time of the navigation system response and hull vertical movement response, and adjusts the front flap. 14 and the rear flaps 26 to 29 are automatically controlled so that the blade depth is constant.

This deep depth automatic control device FDC has a bow altitude detector 50
The bow altitude detector 50 detects the distance from a predetermined part of the bow section to the sea surface in real time, and this detector 5
A spectrum analysis calculation device 90 that receives an altitude signal HD as a wave height signal from 0, and an encounter wave prediction calculation that receives the output of this spectrum analysis calculation device 90 and predicts and calculates an encounter wave that the front strut 12 will encounter in the near future. A device 91;
A flap control signal generator 92 receives a signal regarding the wave height of the encountered wave from the encountered wave prediction calculation device 91 and outputs flap control signals to the front flap servo amplifier 80 and the port and starboard flap servo amplifiers 82 to 85, respectively. We are prepared.

The bow altitude detector 50 detects the distance to the sea surface by emitting ultrasonic waves toward the sea surface below and detecting the reflected waves, and outputs the altitude signal HD every moment. The spectrum analysis calculation device 90 converts the altitude signal HD into
An existing well-known spectrum analysis calculation device 90 consisting of an A/D converter that performs /D conversion, a microcomputer, etc., performs high-speed real-time analysis of the altitude signal HD during the latest past predetermined time tP (see Fig. 7). By performing spectrum analysis using Fourier transform processing, the frequency, amplitude, and phase of all waves in the time series included in the altitude signal HD are calculated. The spectrum distribution obtained in the process of spectrum analysis is illustrated as shown in FIG.

The encountered wave prediction calculation device 91 is composed of a microcomputer, a D/A converter, etc., and receives time-series wave frequency, amplitude, and phase data obtained as the calculation results from the spectrum analysis calculation device 90. Predetermined high frequency ω,1
(See FIG. 8) A wave height function H(t) including time t as a parameter is determined by inverse Fourier transform using data of a time-series wave of a lower frequency. However, the above wave height function H(
t) shall be determined using the mean sea level LO, which is calculated separately, as the zero level (see Figure 7). This wave height function H(t) gives future waves entering the sensing region 93 of the altitude detector 50 in the range of 1>0, but the sensing region 93 and the front strut 12 are close to each other and underwater. Since the winged ship JF travels at a high speed of 45 knots, the wave height function H(t) can be set to give a future encountering wave that will encounter the front strut 12 in the range of 1>0. On the other hand, the time required for the rear struts 1-20 and 22 to meet the wave that the front strut 12 encountered is Δ
L (This is obtained by the distance between the front and rear struts/ship speed,
If the ship speed is constant, the wave height function H
(t-Δt) gives the future encounter waves at which the rear struts 20 and 22 meet in the range of (−Δt)>0.

By the way, the response delay time of the front flap drive system (servo amplifier 80 and actuator 30) is tl, the response delay time of vertical movement response of the hull 10 is t2, tr'= (tl
+t2), there is the response delay time tF, so in rough seas under rough weather, even if the flap control signal is output immediately after detecting the wave height, it will not be in time, and the response delay time tF will always adapt to the encountering waves in the near future. It is necessary to output a flap control signal to

Therefore, the encountering wave prediction calculation device 91 uses the wave height function H(
t) to calculate the wave height H6=H(tF) at t=tF in real time, and use H(t-Δt) to calculate the wave height H at t=tF, =H(tF-Δt) in real time. These signals are then D/A converted and output to the flap control signal generator 92 in real time. That is,
The wave height H, is the wave height of the encountering wave where the front struts 12 meet in the near future by time tF, and the wave height HA is the wave height of the meeting wave where the rear struts 20 and 22 meet in the near future by time tF.

The flap control signal generator 92 receives the signal with the wave height H1 and the signal with the wave height HA in real time, and
, generates a front flap control signal HFA based on the pulse height HA and a rear flap control signal f (AA) based on the wave height HA, outputs the front flap control signal HFA to the front flap servo amplifier 80 in real time, and outputs the rear flap control signal HFA to the front flap servo amplifier 80 in real time. HAA
is output to rear flap servo amplifiers 82 to 85 in real time. However, the front flap control signal HFA is proportional to the wave height Hr, and moves the front flap 14 downward when H,>O, and moves the front flap 14 downward when H,<0.
This is a signal that causes each of the signals 4 and 4 to tilt upward. Further, the rear flap control signal HA is proportional to the wave height HA and
〉When 0, move the rear flaps 26 to 29 downward and H
When o<0, the signal causes each of the rear flaps 26 to 29 to tilt upward.

Therefore, when the front flap 14 is tilted and driven by the control signal HFA and the hull 10 starts responding, the front strut 12 encounters a wave with a wave height corresponding to the control signal HFA, and the control signal HAA causes the rear flap 26 to 29
is tilted and the hull 10 starts responding, the rear struts 20 and 22 will encounter waves with a wave height corresponding to this control signal HAA, so the blade depth of the front wing 13 and the blade depth of the rear wing 24 will be The blade depth is automatically controlled in real time to the set blade depth set by the depth setting lever 61.

As a first modification, in order to simplify the deep automatic control device FDC, calculation of the wave height function H (-ΔL) is omitted, and flap control signals are output to the port and starboard flap servo amplifiers 82 to 85. may be omitted.

As a second modification, as shown in FIGS. 9 to 11, the altitude signal HD from the bow altitude detector 50, the signal VD from the bow vertical acceleration 52, and the signal P from the pitch gyro 55
An altitude signal correction device 94 is provided which receives the signal RD from the roll gyro 56 and the altitude signal correction device 94, and outputs a corrected altitude signal HDm from the altitude signal correction device 94 to the spectrum analysis calculation device 90.

The altitude signal correction device 94 is configured to control the signal HD/VD/PD.
- It consists of an A/D converter for A/D converting the RD, a microcomputer, etc. As shown in FIG. 10, when the pitch angle θ of the hull 10, the altitude signal correction device 94 sets the corrected altitude signal HDm−altitude signal HDXCO5θ, and when the roll angle θ of the hull 10, the altitude signal correction device 94 sets the corrected altitude signal HDm=altitude signal HDXC.
The altitude signal is corrected as OSθ. Furthermore, the altitude signal correction device 94 calculates in real time the cumulative value ΔHD of the amount of vertical movement of the bow caused by the vertical acceleration of the bow after leaving port and moving to Inuzashi, and adds this to the altitude signal HD (ΔHD<O
(subtraction) to perform corrections due to vertical acceleration. In this case, since a digital signal is output from the altitude signal correction device 94 to the spectrum analysis calculation device 90, the A/D converter of the spectrum analysis calculation device 90 is omitted.

The spectrum analysis calculation device 9o, the encounter wave prediction calculation device 91, and the flap control signal generator 92 can be configured using a computer as a main component, either alone or together with other devices, and the altitude signal correction device 94 can also be configured by The same is true.

As described above, by correcting the altitude signal HD using the pitch angle θ, roll angle θ, and vertical acceleration, highly accurate wave height data can be obtained, and the accuracy of deep automatic control can be improved.

As explained above, according to this deep-depth automatic control device FDC, encountering waves in the near future are predicted from the wave height detection values during the latest past predetermined time, and the system takes measures to deal with the encountering waves in advance of the encountering waves. By outputting the flap control signal and controlling the front flap 14 and the rear flaps 26 to 29, the blade depth can be automatically controlled optimally and precisely without any influence of response delay.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and Fig. 1 is a right side view of a hydrofoil, Fig. 2 is a schematic perspective view showing the arrangement of detection equipment, etc. of the hydrofoil, and Fig. 3 is a hydrofoil. Fig. 4 is a block diagram of the main parts of the control system, Fig. 5 is a block diagram of the automatic blade depth control J111 device, and Fig. 6 is an explanation of the wing running state of the hydrofoil boat. Figure 7 is a time chart of detected wave height and predicted wave height, Figure 8 is a spectrum distribution diagram of waves detected during the latest past predetermined time, and Figure 9 is a deep depth diagram according to the second modification. A block diagram of the main parts of the automatic control device, Fig. 10 is an explanatory diagram of wave height correction by pitch angle, Fig. 11
The figure is an explanatory diagram of wave height correction based on roll angle. JF... Hydrofoil boat, 13... Front wing, 14... Front flap, 24... Rear wing, 26-29... Rear flap, 30, 32-35... Flap servo amplifier, 50... Bow. Altitude detector, 90... Spectrum analysis calculation device, 91... Encountering wave prediction calculation device, 9
2. Flap control signal generator. Patent applicant Kawasaki Heavy Industries, Ltd.

Claims (1)

[Claims] (1) A front wing and a rear wing provided at the bow and stern, respectively, a front flap provided on the front wing, a rear flap provided on the rear wing, and a front flap that drives the front flap. In a hydrofoil boat equipped with a drive means and a rear flap drive means for driving a rear flap, a wave height detection means for detecting a distance from a predetermined part of the bow section to a wave surface, and receiving a wave height signal from the wave height detection means, spectrum analysis calculation means for performing spectrum analysis in real time on a time-series wave height signal during a predetermined time period in the latest past and calculating and outputting the frequency, amplitude, and phase of each wave; and an output from the spectrum analysis calculation means. is received in real time and uses the frequency, amplitude, and phase of a time series of waves with a frequency lower than a predetermined high frequency to predict and calculate the wave height of the encountering wave that the front strut will encounter in the near future after a set time from the present. and a flap proportional to the height of the encountering wave so as to suppress fluctuations in the blade depth of the front wing by receiving a signal regarding the height of the encountering wave from the encountering wave prediction calculation means in real time. An automatic blade depth control device for a hydrofoil boat, comprising: flap control signal generation means for generating a control signal and outputting it to a front flap drive means.