US 20190155310A1( 19) United States(12 )KIM
Patent Application Publication ( 10) Pub . No.: US 2019 /0155310 A1(43) Pub . Date:
G05D 1/08( 54 ) ROUTE SETTING METHOD FOR
UNDERWATER VEHICLE , UNDERWATERVEHICLE OPTIMUM CONTROL METHOD(2006 .01)

(2006 . 01)

G05D 1/04
GO1C 21/20

USING SAME, AND UNDERWATER(52) U . S . CI.

VEHICLEMay 23 , 2019(2006 .01 )G05D ITV
1/ 10 12(2013.01); B63G 8/ 001

CPC . .. .. .. .. . .. .. . GOD( 2013 .01) ; B636 2008 /004 ( 2013 .01); G05D

(71 ) Applicant: NATIONAL INSTITUTE OF
MARITIME, PORT AND AVIATIONTECHNOLOGY, Tokyo ( JP )(72 ) Inventor: Kangsoo KIM , Tokyo (JP )(57)(21 ) Appl. No.:
(22 ) PCT Filed :waypoint input step for inputting underwater waypoints of

1/048 (2013 .01); G01C 21/ 203 (2013. 01 );G05D 1/0875 (2013 .01 )15 /781,566
Dec. 9 , 2016

The route setting method is provided with : an underwater

the underwater vehicle ; a target value setting step for setting

PCT/JP2016 /086723(86 ) PCT No .:$ 371 (c )(1),(30 )initial target values at the underwater waypoints; an underwater navigation simulation step for simulating an underwater navigation route of the underwater vehicle by using

Jun . 5 , 2018(2 ) Date :water bottom topography data and the target values on theForeign Application Priority Data

Dec. 9, 2015 ( JP ) .........

basis of a dynamics model of the underwater vehicle ; and atarget value update step for updating the target values on thebasis of an objective function which is calculated on the.............. 2015 -240252

basis of the underwater navigation route obtained throughthe simulation in the underwater navigation simulation step .
Optimum target values are derived by repeating the underwater navigation simulation step and the target value update
step .

Publication Classification(51 ) Int. Cl.

G05D 1/ 10

B63G 8/ 00

ABSTRACT( 2006 .01)

( 2006 .01)

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SUBMARINETOPGRAHYMay 23, 2019

US 2019 /0155310 A1
ROUTE SETTING METHOD FOR
UNDERWATER VEHICLE , UNDERWATERVEHICLE OPTIMUM CONTROL METHODUSING SAME, AND UNDERWATER[0008 ] Patent Document 3: JP 2003-127983 A[0009 ] Patent Document 4 : JP 2007- 292729 A[0010 ] Patent Document 5 : JP 2015 -063181 A

VEHICLETECHNICAL FIELD[ 0001] The present invention relates to a route setting
method for an underwater vehicle, an optimum control
method for an underwater vehicle using the same, and anunderwater vehicle.

SUMMARY

Technical Problem[0002 ] In recent years, the underwater bottom is drawing
attention as a supply source of all resources ranging from[0011 ] A reflection intensity of an inspection signal suchas a sonic wave is in inverse proportion to an incident angle
to the underwater bottom . In other words, the reflection
intensity is remarkably weakened compared to a normal
incidence ( an incident angle of “ O ” ) when the incident angle
is large at a region which is shallow with respect to theunderwater bottom . Therefore, in a case where a submarine

necessity for inspecting the underwater bottom . In thereflection signal is correlated to the topography and is weakmethod using signals such as sonic waves, lasers , visible

Further, in a complicated submarine topography the problem
of multipath is remarkable compared to a flat underwater

However, since these signals suffer a propagation loss, thesesignals are used at positions as close as possible to thebottom . As a result, a height of a vehicle measured by a

BACKGROUND
mineral resources . Accordingly, there has been an increasing

inspection of the underwater bottom , a remote sensing

light, and electromagnetic waves is normally employed .

underwater bottom in order to obtain information of highresolution and high accuracy . Therefore , there is a need for

topography has complicate ups and downs, an intensity of acompared to a case where the submarine topography is flat.

height indicator is lowered in reliability .
[0012 ] For such a reason , a height-based vertical control
of a vehicle is rarely employed in view of the safe navigationa technology that enables an underwater vehicle (forexcept a case where information of the height is stably
obtained with high accuracy similarly to the flat underwater

desired route and in a desired attitude near the underwaterbottom .

bottom , but a depth -based vertical control of a vehicle isexample , a submersible vessel) to navigate ( sails ) on aemployed in many cases.

[0003] There is disclosed a technique that the underwater
vehicle is provided with a depth setting unit to set a depth

applied to underwater vehicle navigation , a target depth isthe basis of a predetermined depth (Patent Document 1 ).

set such that the underwater vehicle is controlled to be safe
from the bottom collision . However, a relation between athereof, and performs control on driving of stern steering on

Herein , a limit circuit is provided between the depth setting[0013 ] In an actual situation , when the depth control issubmarine topography and the dynamics of an underwater

unit and a depth control unit such that the underwater vehicle

vehicle is extremely difficult to be evaluated in setting theis controlled so as not to come into contact with thetarget depth . Further, in a rough submarine topography there[0004 ] In relation to an automatic pilot of the underwater
vehicle, there is disclosed a technique that an estimation
accuracy of a dynamic state quantity is improved using atarget depth is set to make the underwater vehicle separated
from the underwater bottom by a sufficient distance in orderunderwater bottom .

dynamic model to trace a dynamic characteristic of theunderwater vehicle in order to estimate its dynamic state(Patent Document 2 ) . In addition , there is disclosed atechnique of controlling the steering of the underwater
vehicle in consideration of an influence of tidal currents(Patent Document 3 ).

is a concern of bottom collision . On the other hand, when the

to avoid bottom collision , the quality of data obtained fromdegraded . Therefore , in practice, the target depth is set tothe underwater bottom and the resolution are remarkably

make the underwater vehicle appropriately separated fromthe underwater bottom on the basis of experience andintuition . In addition , the underwater vehicle may take aspecific attitude ( for example , an attitude parallel to the[ 0005 ] In addition , there is a need to acquire an accurate

underwater bottom ) according to a type of sensor used in theposition of the underwater vehicle to control the navigation

inspection of the underwater bottom . In this case , it isof the underwater vehicle . Moreover, there is disclosed adesirable that the underwater vehicle navigate on a route
approximating most to the slopes of the underwater bottom

positioning technique in which the depths are measured at aplurality of positions using a multi- beam depth sounder towhile avoiding collision with the underwater bottom .

specify the position of the underwater vehicle (Patent Document 4 ). There is disclosed a technique in which the vehicle

ments 1 to 5 about a configuration that an underwater

attitude of the underwater vehicle is acquired , a safety region

underwater navigation route which can make the underwater

state information such as a speed , a depth , a height, and an

for a safe navigation is set on the basis of the state infor
mation , and the underwater vehicle is controlled to navigate
in the safety region (Patent Document 5 ) .

CITATION LIST
Patent Literature

10006 ] Patent Document 1: JP 63 - 273797 A[0007 ] Patent Document 2: JP 05 - 016878 A[0014 ] There is no consideration in all of Patent Docu

waypoint is determined in order to obtain an optimum

vehicle approach the underwater bottom while preventing
collision with the underwater bottom .

[0015 ] The invention has been made in view of at least oneof the above problems, and an object thereof is to provide aroute setting method for an underwater vehicle , an optimum
control method for an underwater vehicle using the same,and the underwater vehicle , so that an optimum route is set

with respect to a reference to make the underwater vehicle
controlled to navigate .

US 2019 /0155310 A1
Solution to Problem[0016 ] A route setting method for an underwater vehicleaccording to the present invention includes : inputting an
underwater waypoint of an underwater vehicle ; setting an
initial target value in the underwater waypoint ; simulating

May 23, 2019[0024] Furthermore, a value of the objective function ispreferably a total sum of absolute values of differences
between the calculated underwater navigation heights at aplurality of the underwater waypoints and the minimum
allowable height, or a total sum of squares of the differences,and in the updating of the target value, the target height isan underwater navigation route of the underwater vehicle
with respect to the target value on the basis of a dynamic
model of the underwater vehicle using data of a submarine

preferably updated such that the value of the objective

the target value on the basis of an objective function which

ence attitude of the underwater vehicle at the underwater
waypoint.

topography as a reference and the target value ; and updating
is calculated on the basis of the underwater navigation routeobtained in the simulating of the underwater navigation ,wherein the target value is optimized by repeatedly perform
ing the simulation of the underwater navigation and the

updating of the target value.

[0017 ] Here, the target value is preferably a target depth in

the underwater waypoint.

[ 0018 ]. Furthermore, the route setting method for an underwater vehicle preferably further includes : setting a minimum
allowable height of the underwater vehicle , and in thesimulation of the underwater navigation , a calculated underwater navigation height of the underwater vehicle withrespect to the target depth is preferably simulated on thebasis of the dynamic model of the underwater vehicle using

the data of the submarine topography and the target depth ,and the calculated underwater navigation height and theminimum allowable height are preferably compared toderive the optimum target depth .
[0019] Furthermore, in the updating of the target value, thetarget depth is preferably updated such that a minimum
value of the calculated underwater navigation heightapproaches the minimum allowable height in a case where

function is decreased .

[0025 ] Here, the target value is preferably a target refer[0026 ] Furthermore , the route setting method for an underwater vehicle preferably further includes: setting a minimum
allowable height of the underwater vehicle , and in thesimulation of the underwater navigation , a calculated underwater navigation height of the underwater vehicle withrespect to the target reference attitude is preferably simu
vehicle using the data of the submarine topography and thelated on the basis of the dynamic model of the underwatertarget reference attitude, and the calculated underwaternavigation height and the minimum allowable height are

preferably compared to derive the optimum target reference
attitude .
10027 ]. Furthermore , in the updating of the target value , thetarget reference attitude is preferably updated such that aminimum value of the calculated underwater navigation

height approaches the minimum allowable height in a casewhere there is a difference between the minimum value ofthe calculated underwater navigation height and the mini

mum allowable height.
10028 ]. Furthermore , a value of the objective function ispreferably a total sum of absolute values of differences

between the calculated underwater navigation heights at athere is a difference between the minimum value of thecalculated underwater navigation height and the minimum
allowable height.
[0020] Furthermore , a value of the objective function isplurality of the underwater waypoints and the minimum
allowable height, or a total sum of squares of the differences,

between the calculated underwater navigation heights at aplurality of the underwater waypoints and the minimum

100291. Furthermore , the number of repetitions of the simu
lation of the underwater navigation and the updating of theallowable height, or a total sum of squares of the differences ,and in the updating of the target value, the target depth istarget value is preferably set in advance .

preferably updated such that the value of the objective

instead of the data of the submarine topography. In addition ,a reference attitude of the underwater vehicle at the under

preferably a total sum of absolute values of differences

function is decreased .

[0021] Furthermore, the target value is preferably a target

height at the underwater waypoint .
0022] Furthermore, the route setting method for an underwater vehicle preferably further includes : setting a minimum
allowable height of the underwater vehicle, and in thesimulation of the underwater navigation , a calculated underwater navigation height of the underwater vehicle withrespect to the target height is preferably simulated on thebasis of the dynamic model of the underwater vehicle using

the data of the submarine topography and the target height,
and the calculated underwater navigation height and theminimum allowable height are preferably compared toderive the optimum target height.
[0023 ] Furthermore, in the updating of the target value , thetarget height is preferably updated such that a minimum
value of the calculated underwater navigation heightapproaches the minimum allowable height in a case where
there is a difference between the minimum value of thecalculated underwater navigation height and the minimum
allowable height.

and in the updating of the target value , the target reference
attitude is preferably updated such that the value of theobjective function is decreased .

[0030 ] Furthermore, a reference route is preferably usedwater waypoint is preferably used instead of the data of thesubmarine topography. Furthermore , reference attitude

angles of the underwater vehicle at the underwater waypoint
are preferably used instead of the data of the submarine

topography.
10031 ] An optimum control method for an underwater

vehicle according to the present invention includes control

ling the underwater vehicle using the optimum target value
obtained in the route setting method for an underwater

vehicle described above .

[0032 ] Furthermore , the optimum target value and a posi
control a motion control system of the underwater vehicleaccording to a comparison result.
[0033] Furthermore , the underwater vehicle preferablytion of the underwater vehicle are preferably compared tosurfaces urgently in a case where the optimum target value

and the position of the underwater vehicle deviate from apredetermined condition .
[0034] Furthermore , an observation control is preferably
performed to observe a submarine topography .

US 2019 /0155310 A1[0035 ] An underwater vehicle according to the present
invention preferably includes : a target value acquisition unit

May 23, 2019tion height and the minimum allowable height are compared
to derive the optimum target depth . Therefore, it is possible

which acquires the optimum target value acquired in theroute setting method for an underwater vehicle describedto set a route in which the underwater vehicle navigates
underwater to be the optimum target depth at the underwater
waypoint while avoiding the underwater vehicle fromand a motion control unit which controls a drive unit using

approaching the underwater bottom below the minimum[ 0036 ] Here , the underwater vehicle preferably further
includes : at least one of a depth measuring unit, a heightmeasuring unit , and a attitude measurement unit, and the
motion control unit preferably compares a measurement
value of at least one of the depth measuring unit, the heightmeasuring unit, and the attitude measurement unit with thetarget value stored in the storage unit to control the drive[0043] In addition , in the updating of the target value , theabove; a storage unit which stores the acquired target value ;the target value stored in the storage unit.

unit .

[0037] Furthermore , the underwater vehicle preferably

further includes : an obstacle detection unit, and the motion
control unit preferably controls the drive unit according to a

detection result of the obstacle detection unit .

[0038 ] Furthermore, the underwater vehicle preferably

further includes : an inertial navigation unit, and the motion
control unit preferably controls the drive unit on the basis ofan output of the inertial navigation unit.

0039] Furthermore, the underwater vehicle preferably
further includes : an observation unit which observes asubmarine topography .
Advantageous Effects of Invention[ 0040 ] A route setting method for an underwater vehicleaccording to claim 1 includes inputting an underwater
waypoint of an underwater vehicle , setting an initial target
value in the underwater waypoint, simulating an underwaternavigation route of the underwater vehicle with respect tothe target value on the basis of a dynamic model of theunderwater vehicle and the data of a submarine topography

allowable height.

target depth is updated such that a minimum value of thecalculated underwater navigation height approaches theminimum allowable height in a case where there is adifference between the calculated underwater navigation

height and the minimum allowable height. Therefore , it ispossible to set the optimum target depth such that theunderwater vehicle approaches the underwater bottom as
close as possible at the underwater waypoint while avoiding
the underwater vehicle from approaching the underwaterbottom below the minimum allowable height.
[0044 ] In addition , the objective function is a total sum ofabsolute values of differences between the calculated underwater navigation heights at a plurality of the underwater
waypoints and the minimum allowable height, or a total sumof squares of the differences. In the updating of the target
value , the target depth is updated such that the objectivefunction is decreased . Therefore , it is possible to set the

optimum target depths at the plurality of underwater way
points such that a total sum of absolute values of differences

between the calculated underwater navigation heights at theplurality of underwater waypoints and the minimum allow
able height, or a total sum of squares of the differences isminimized .
[0045 ] In addition , the target value is a target height at theunderwater waypoint. Therefore , it is possible to set an
optimum target height which is optimized to the submarine
topography at the underwater waypoint. With this configu
ration , the underwater vehicle can navigate to be the opti

as a reference and the target value, and updating the target
value on the basis of an objective function which is calcu

mum target height at the underwater waypoint. Further, it isobtained in the simulation of the underwater navigation . The
target value is optimized by repeatedly performing the

optimum underwater navigation height according to a purpose such as observation .

the target value . Therefore , it is possible to set an optimum

water vehicle includes setting a minimum allowable heightof the underwater vehicle . In the simulation of the underwater navigation , a calculated underwater navigation height

lated on the basis of the underwater navigation routesimulation of the underwater navigation and the updating oftarget value which is optimized to the submarine topography

at the underwater waypoint. With this configuration , theunderwater vehicle can navigate underwater with an opti

mum target value at the underwater waypoint. Further , it ispossible to set a route which can realize the navigation in an

optimum navigation state according to a purpose .
10041] Herein , the target value is a target depth at theunderwater waypoint. Therefore , it is possible to set an

optimum target depth which is optimized to the submarine

topography at the underwater waypoint. With this configu

ration, the underwater vehicle can navigate to be the opti

mum target depth at the underwater waypoint. Further, it ispossible to set a route which can realize the navigation of the
optimum depth according to a purpose such as observation .

0042] In addition , the route setting method for an underpossible to set a route which can realize the navigation of the[0046 ] In addition , the route setting method for an underof the underwater vehicle with respect to the target height issimulated on the basis of the dynamic model of the underwater vehicle using the data of the submarine topography
and the target height , and the calculated underwater navi
gation height and the minimum allowable height are com
pared to derive the optimum target height. Therefore , it ispossible to set a route in which the underwater vehicle
navigates underwater to be the optimum height at theunderwater waypoint while avoiding the underwater vehicle
from approaching the underwater bottom below the mini
mum allowable height.
[0047 ] In addition , in the updating of the target value , thetarget height is updated such that a minimum value of thewater vehicle includes setting a minimum allowable heightcalculated underwater navigation height approaches theof the underwater vehicle. In the simulation of the underwater navigation , a calculated underwater navigation heightminimum allowable height in a case where there is adifference between the calculated underwater navigationof the underwater vehicle with respect to the target depth isheight and the minimum allowable height. Therefore , it ispossible to set the optimum target height such that theunderwater vehicle approaches the underwater bottom as

simulated on the basis of the dynamic model of the underwater vehicle using the data of the submarine topography
and the target depth , and the calculated underwater naviga

close as possible at the underwater waypoint while avoidingUS 2019 /0155310 A1
the underwater vehicle from approaching the underwaterbottom below the minimum allowable height.
[ 0048 ] In addition , the objective function is a total sum ofabsolute values of differences between the calculated underwater navigation heights at a plurality of the underwater
waypoints and the minimum allowable height, or a total sumof squares of the differences. In the updating of the target
value, the target height is updated such that the objectivefunction is decreased . Therefore , it is possible to set the
optimum target heights at the plurality of underwater way
points such that a total sum of absolute values of differences

May 23, 2019[0053] In addition, the number of repetitions of the simu
lating of the underwater navigation and the updating of thetarget value is set in advance. Therefore , it is possible tocomplete an underwater navigation simulation an appropri
ate number of times .

[0054 ] In addition , a reference route is used instead of thedata of the submarine topography . Alternatively , reference
attitude angles of the underwater vehicle in the underwater
waypoint are used instead of the data of the submarine

topography. Therefore , it is possible to optimize the target
value such that the underwater vehicle approaches the

between the calculated underwater navigation heights at theplurality of underwater waypoints and the minimum allow
able height, or a total sum of squares of the differences iswater waypoint.

minimized .

vehicle according to the present invention preferably con[ 0049 Herein , the target value is a target reference attitudeof the underwater vehicle at the underwater waypoint.
Therefore , it is possible to set an optimum target reference
attitude which is optimized to the submarine topography at
the underwater waypoint. With this configuration , the underreference route or the reference attitude angles at the under[0055 ] An optimum control method for an underwater

trols the underwater vehicle using the optimum target value
obtained in the route setting method for the underwater

vehicle . Therefore , it is possible that the underwater vehicle
navigates underwater with the optimum target value which
is optimized to the submarine topography at the underwater

water vehicle can navigate to be the optimum target reference attitude at the underwater waypoint . Further , it is

waypoint. Further , it is possible to set a route which canpossible to set a route which can realize the navigation of theaccording to a purpose .

optimum underwater navigation attitude according to a
purpose such as observation .

[ 0050 ] In addition , in the simulating of the underwaternavigation , a calculated underwater navigation height of theunderwater vehicle with respect to the target reference

attitude is simulated on the basis of the dynamic model ofthe underwater vehicle using the data of the submarine

topography and the target reference attitude, and the calcu

lated underwater navigation height and the minimum allow

able height are compared to derive the optimum target

reference attitude. Therefore , it is possible to set a route inwhich the underwater vehicle navigates underwater to be theoptimum target reference attitude at the underwater way

point while avoiding the underwater vehicle from approaching the underwater bottom below the minimum allowableheight .

realize the navigation in an optimum navigation state[0056 ] Herein , the optimum target value and a position of
the underwater vehicle are compared to control a motion
control system of the underwater vehicle according to acomparison result. Therefore , it is possible to specificallyrealize the optimum control method for the underwater

vehicle .

[0057 ] In addition , the underwater vehicle urgently in acase where the optimum target value and the position of theunderwater vehicle deviate from a predetermined condition .
Therefore , it is possible to avoid a risk such as a case where

the underwater vehicle is about to collide with an obstacle .
[0058 ] In addition , an observation control is performed toobserve a submarine topography. Therefore , it is possible toperform observation while navigating in the underwater[0051] In addition , in the updating of the target value, thetarget reference attitude is updated such that a minimum

navigation state which is appropriate to the observation .
[0059 ] An underwater vehicle according to the present

value of the calculated underwater navigation height

which acquires the optimum target value acquired in theapproaches the minimum allowable height in a case where

invention preferably includes a target value acquisition unit
route setting method for the underwater vehicle , a storage

there is a difference between the minimum value of thecalculated underwater navigation height and the minimum

unit which stores the acquired target value, and a motion

target reference attitude such that the underwater vehicle

stored in the storage unit. Therefore , it is possible to performallowable height. Therefore , it is possible to set the optimum
approaches the underwater bottom as close as possible at theunderwater waypoint while avoiding the underwater vehicle
from approaching the underwater bottom below the mini

control unit which controls a drive unit using the target value
the underwater navigation with the optimum target value
which is optimized to the submarine topography at theunderwater waypoint. Further, it is possible to set a route

mum allowable height.
[0052 ] In addition , a value of the objective function is a
total sum of absolute values of differences between thewhich can realize the navigation in an optimum navigation

or a total sum of squares of the differences . In the updating

pares a measurement value of at least one of the depth
measuring unit , the height measuring unit, and the attitude

calculated underwater navigation heights at a plurality of theunderwater waypoints and the minimum allowable height,of the target value, the target reference attitude is updated
such that the value of the objective function is decreased .

Therefore , it is possible to set the optimum target reference

attitude at the plurality of underwater waypoints such that a
total sum of absolute values of differences between thecalculated underwater navigation heights at the plurality ofunderwater waypoints and the minimum allowable height,
or a total sum of squares of the differences is minimized .

state according to a purpose .
100600. Herein , the underwater vehicle includes at least oneof a depth measuring unit, a height measuring unit, and an

attitude measurement unit. The motion control unit com

measurement unit with the target value stored in the storage
unit to control the drive unit. Therefore , it is possible tospecifically realize the optimum control method for theunderwater vehicle which obtains the optimum target value.
[0061] In addition, the underwater vehicle includes an
obstacle detection unit. The motion control unit controls thedrive unit according to a detection result of the obstacle

US 2019 /0155310 A1
detection unit. Therefore, it is possible to avoid a risk suchas a case where the underwater vehicle is about to collidewith an obstacle .

[0062] In addition , the underwater vehicle includes aninertial navigation unit. The motion control unit controls thedrive unit on the basis of an output of the inertial navigation

May 23, 2019
vehicle 100 . The support ship 300 and the underwater

vehicle 100 both can ascertain the relative position throughan acoustic communication device 320 . Therefore , the geo

graphical position of the underwater vehicle 100 can beascertained in the support ship 300 and /or the underwater

unit . Therefore, it is possible to set the optimum target value

vehicle 100 by combining the geographical position
obtained in the support ship 300 and the relative position

underwater waypoint only by the subject vehicle without

position detection unit of the underwater vehicle 100.

which is optimized to the submarine topography at theacquiring the position information from the outer side.
[0063] In addition , the underwater vehicle includes anobservation unit which observes a submarine topography.
Therefore , it is possible to perform observation while navi
gating in the underwater navigation state which is appropri

ate to the observation .
BRIEF DESCRIPTION OF DRAWINGS
10064 ) FIG . 1 is a conceptual diagram illustrating a con
figuration of an underwater vehicle according to an embodi
ment of the invention .

[0065 ] FIG . 2 is a diagram illustrating a configuration ofa route setting device of the underwater vehicle according to
the embodiment of the invention .

[0066 ] FIG . 3 is a flowchart of a route setting method forthe underwater vehicle according to the embodiment of theinvention .
[ 0067 ] FIG . 4 is a functional block diagram of the routesetting device of the underwater vehicle according to theembodiment of the invention .
[0068 ] FIG . 5 is a diagram for describing a route setting

obtained in the acoustic positioning device 310 or the[0074 ] <Configuration of Underwater Vehicle >[0075 ] As illustrated in a conceptual diagram of FIG . 1,
the underwater vehicle 100 according to the embodiment of

the invention is configured by a hull 10 , a main propeller 12 ,a main propeller drive motor 14 , a vertical rudder 16 , avertical rudder drive motor 18 , a horizontal rudder 20 , ahorizontal rudder drive motor 22 , a depth indicator 24 , aheight indicator 26 , an obstacle sensor 28 , an observation

sensor 30 , an inertial navigation device 32 which is aposition detection unit, a control device 34 , an acoustic

communication device 36 , and an acoustic positioning
device 38 . The underwater vehicle 100 is , for example , anautonomous underwater vehicle (AUV ),but the invention is

not limited thereto .

[0076 ] The hull 10 is a sealable structure which makes

spaces such as cabins. The hull 10 is configured by a metalor reinforced plastic material, and also serves to mechani

cally support components of the underwater vehicle 100 .

10077] The main propeller 12 is a component which
generates a driving force to propel the underwater vehicle

process of the underwater vehicle according to the embodi

100 . The main propeller 12 is configured by a propeller andment of the invention .

14 is a motor to apply the driving force to the main propeller
12 . The main propeller drive motor 14 receives a drive
control signal from the control device 34 to rotatably drive
the rotation shaft of the main propeller 12 by power from a[0069 ] FIG . 6 is a flowchart of an optimum navigation

control of the underwater vehicle according to the embodi
ment of the invention .
0070 ] FIG . 7 is a functional block diagram of the underwater vehicle according to the embodiment of the invention .

a rotation shaft, for example. The main propeller drive motor

battery 14a at the rotation number and torque according to[0071] FIG . 8 is a diagram illustrating an observation

the drive control signal. With this configuration , the propel
ler connected to the drive shaft is rotated , and applies avehicle according to the embodiment of the invention .

propulsive force to the underwater vehicle 100 .

system of a submarine topography using the underwater

DESCRIPTION OF EMBODIMENTS[0072 ] <System Configuration >[ 0073] FIG . 8 is a diagram illustrating an observation
system of a submarine topography using an underwater
vehicle according to an embodiment of the invention . The

observation system is configured by an underwater vehicle

100 which submerges into the water, a route setting device
setting device is mounted . The underwater vehicle 100

200, and a support ship 300 on thewater, on which the routenavigates along an optimum underwater navigation routewhich is set to make a closest approach to the underwaterbottom while preventing collision in order to observe asubmarine topography 400 at an underwater waypoint. The
support ship 300 receives a GPS signal from a satellite 500
to determine its own geographical position . Therefore, ageographical position of the underwater vehicle 100 can be
known . In the support ship 300 , an acoustic positioning
device 310 is mounted , so that a relative position of theunderwater vehicle 100 in the water from the support ship

300 can be ascertained . In addition , the underwater vehicle
100 can detect the relative position to the support ship 300
using a position detection unit mounted in the underwater[0078 ] The vertical rudder 16 is a rudder to turn (revolve )the hull 10 in the right and left direction. The hull 10 can be

revolved to the left or right side by inclining the verticalrudder 16 to the right or left side with respect to the hull 10 .
The vertical rudder drive motor 18 is a motor to generate adriving force to rotate the vertical rudder 16 . The verticalrudder drive motor 18 receives a vertical steering control
signal from the control device 34 to rotatably drive thevertical rudder 16 to form attitude angles corresponding to
the vertical steering control signal .
[0079 ] Further, the hull 10 may be configured to turn(revolve ) in the right and left direction such that the main
propellers 12 are individually provided on the right and left
sides to balance the propulsive force of the right and left
main propellers 12 without depending on the vertical rudder
16 .

[0080 ] The horizontal rudder 20 is a rudder to raise andfall the hull 10 . The hull 10 can pitch up or down by
inclining up or down the horizontal rudder 20 with respect

to the hull 10 . The horizontal rudder drive motor 22 is a
motor to generate a driving force to rotate the horizontal
rudder 20 . The horizontal rudder drive motor 22 receives ahorizontal steering control signal from the control device 34

US 2019 /0155310 A1
to rotatably drive the horizontal rudder 20 to form attitude
angles corresponding to the horizontal steering control sig
nal.
[0081] The depth indicator 24 is a device which measuresa distance (depth ) from the water surface of the underwater
vehicle 100 and outputs the distance . The depth indicator 24

measures a depth from a water pressure applied to the hull

May 23, 2019
inertial navigation device 32 . The acoustic communication

device 36 transmits the information to the outer side of theunderwater vehicle 100 ( for example , a ship on the sea ) . In

addition, the acoustic communication device receives anabsolute position which is measured by a GPS in the outerside (for example , a ship on the sea ).

[0087 ] The acoustic positioning device 38 receives the

10 of the underwater vehicle 100 for example . The depth
indicator 24 outputs the measured depth to the control
device 34 . The height indicator 26 is a device which

sea , the acoustic positioning device 38 acquires information

the underwater vehicle 100 , and outputs the distance . Theof the relative position of the underwater vehicle 100 . The
relative position information is input to the control device

measures a distance (height) from the underwater bottom toheight indicator 26 outputs sonic waves to the lower side of

the hull 10 for example, and measures the height on the basisof a time taken until the sonic waves reflected on theunderwater bottom are received . The height indicator 26

outputs the measured height to the control device 34 .

[0082 ] The obstacle sensor 28 is a sensor to detect an

obstacle which exists in an advancing direction ( front side )of the underwater vehicle 100 . The obstacle sensor 28

outputs the sonic waves to the front side ( or in a slightly
lower direction on the front side) of the hull 10 , for example .
The obstacle sensor measures the presence of an obstacle
and a distance thereto on the basis of a time taken until thesonic waves reflected on the obstacle on the front side arereceived . The obstacle sensor 28 outputs a detection result of

the obstacle to the control device 34 .

relative position between the underwater vehicle 100 and aship on the outer side. When being provided in a ship on the
34 . The control device 34 acquires information of an absolute position of the ship on the sea which is acquired by the
acoustic communication device 36 . The control device canobtain an absolute position of the underwater vehicle 100
from the absolute position of the ship and the relative
position of the underwater vehicle 100 . The control device

34 can correct the position information acquired from theinertial navigation device 32 using the absolute position

information of the underwater vehicle 100 thus acquired .

For example , the control device 34 corrects the position of

the inertial navigation device 32 using the position of theacoustic positioning device 38 in a case where a difference

between the position calculated from the relative position

information acquired from the acoustic positioning device
38 and the position acquired from the inertial navigation[ 0083 ] The observation sensor 30 is a sensor for theobservation of the underwater vehicle 100 . The observation
sensor 30 may be configured by various sensors according todevice 32 is larger than a predetermined value . The inertial
navigation device 32 keeps estimating the position of thethe purpose of the observation . The observation sensor 30

initial value .

may be configured by a sonic wave sensor, an electromag

netic wave sensor, an optical sensor, a pressure sensor , anda thermal sensor , for example . The observation sensor 30

outputs an observed result to the control device 34 .

underwater vehicle 100 using the corrected position as a new[0088] <Route Setting Method for Underwater Vehicle >[0089 ] A route setting process of the underwater vehicle
100 according to this embodiment will be described below .

[0084 ] The inertial navigation device 32 includes an accel

In this embodiment, the description will be given about aeration sensor and a gyro sensor which measure an accel
eration when the hull 10 moves. Position information of thedevice 200 separated from the underwater vehicle 100. In
this case , the invention is not limited to the above configu

hull 10 is obtained by twice integrating the accelerations

measured by these sensors with respect to time. The position
information of the underwater vehicle 100 obtained by thecontrol device 34 is output to the control device 34 .
[0085 ] The control device 34 receives information fromthe depth indicator 24 , the height indicator 26 , the obstacle
sensor 28 , the observation sensor 30 , and the inertial navi
gation device 32 , and controls the navigation of the underwater vehicle 100 on the basis of the information . The

control device 34 controls the main propeller 12 , the verticalrudder drive motor 18 , and the horizontal rudder drive motor
22 on the basis of the position information from the inertial
navigation device 32 , the depth from the depth indicator 24 ,and height information from the height indicator 26 . There
fore , the hull 10 approaches a predetermined underwater
waypoint and a target value (a target depth , a target height,a target attitude, a target attitude angle , etc . ) which is set bya route setting method ( described below ). Navigation con

trol of the control device 34 will be described below .

[0086 ] The acoustic communication device 36 is a device

which communicates with the outer side of the underwater

vehicle 100 through the sonic waves. The acoustic commu
nication device 36 receives information about the results andthe navigation from the control device 34 which are mea

sured by the depth indicator 24 , the height indicator 26 , theobstacle sensor 28 , the observation sensor 30 , and thecase where the route setting is performed by the route setting
ration , and the route setting device 200 may be mounted in

the underwater vehicle 100.

[0090 ] As illustrated in FIG . 2, the route setting device

200 is a computer which includes a processing unit 40 , astorage unit 42 , an input unit 44 , and an output unit 46 . The

processing unit 40 is configured by a CPU . The processing
unit 40 performs the route setting process (described below )by executing a route setting program which is stored in thestorage unit 42 in advance . The storage unit 42 is a storage
device to store the route setting program , a hull motion
calculation model, and various types of data . The storage
unit 42 may be a semiconductor memory and a hard disk , forexample . The input unit 44 includes a device which inputs

information to the route setting device 200 to perform theroute setting process . The input unit 44 may be a keyboard ,a mouse , and a touch panel. In addition , the input unit 44

may acquire information from other devices through a

network interface . The output unit 46 includes a device tooutput information of a route obtained by the route setting
device 200 . The output unit 46 may be a display and aprinter. In addition , information may be output to the control
device 34 of the underwater vehicle 100 through the output
unit 46 as the network interface .
[0091] The route setting process is performed along a
flowchart of FIG . 3 . The route setting device 200 serves asUS 2019 /0155310 A1
the respective units illustrated in a functionalblock diagramof FIG . 4 by executing the route setting process.
[0092] In step S10 , an initial setting is performed . In thisprocess, the route setting device 200 serves as an initial
setting unit 50 . In the initial setting , information of thesubmarine topography 400 is input, themaximum number ofrepetitions (Ne) is set, and a minimum allowable height (ha )is set as a reference using the input unit 44. The informationof the submarine topography 400 is information indicating aheight of topography at every coordinate of the underwaterbottom in a navigation target region of the underwater

vehicle 100 as illustrated with a thick solid line of FIG . 5 .

The maximum number of repetitions (Ne) is a maximum

number of repetitions in the route setting process . The

minimum allowable height ( ha ) is a minimum allowableheight from the underwater bottom to set a route so that theunderwater vehicle 100 does not come into contact with theunderwater bottom .

10093 ]. In step S12 , an input process of the underwater
waypoint is performed . In this process, the route setting

device 200 serves as an underwater waypoint setting unit 52 .
The underwater waypoints are information indicated bydiscrete coordinates on a navigation route of the underwater
vehicle 100 in a plane (the water surface ; a surface parallelto the sea surface ). In other words, the underwater waypoints

are sequentially connected to obtain a two -dimensional
water waypoints are set according to an entire underwaternavigation route plan based on an observation plan innavigation route of the underwater vehicle 100 . The underadvance .

[ 0094 ] In step S14 , initial target values at the respective

underwater waypoints are set. In this process , the routesetting device 200 serves as a target value setting unit 54 . In
this embodiment, the target value is a target depth of theunderwater vehicle 100 . In other words, as illustrated in FIG .
5 , an initial value (illustrated as a white triangle in thedrawing ) of a target depth of the underwater navigation routeof the underwater vehicle 100 is set for every the underwater

waypoint which is input in step S12 .

[ 0095 ] In step S16 , the hull dynamic model is set. In thisprocess, the route setting device 200 serves as a hull

May 23, 2019and is frequently called a hydrodynamic coefficient. The
hydrodynamic coefficient can be obtained by a tank test
using a scale model of the hull or a numerical calculation
using a procedure of a computational fluid dynamics . In theequations of motion , items other than the hydrodynamic
the equations of motion are completed by obtaining thecoefficient are variables and an external force item , so thathydrodynamic coefficient .

[0096 ] In steps S18 to S32 , there are performed theunderwater navigation simulation in which the underwaternavigation route of the underwater vehicle 100 with respect

to the target value is simulated on the basis of the dynamic

model of the underwater vehicle 100 using data and thetarget depth of the submarine topography 400 , and an
optimization analysis in which a target value updatingprocess is repeatedly performed to update the target depth
and the target value target depth ) at the underwater way

point is optimized on the basis of an objective function
which is calculated on the basis of the underwater navigationroute obtained in the underwater navigation simulation .
[0097 ] In step S18 , a counter ie is set to an initial value" O .” The counter ie is used to count the number of repetitionsof the simulation . In step S20 , “ 1” is added to the counter ie.
[0098 ] In step S22 , the underwater navigation simulationis performed . In this process , the route setting device 200
serves as a target value following simulation unit 58 . The
processing unit 40 simulates the underwater navigation routeof the underwater vehicle 100 using the information of thesubmarine topography 400 input in step S10 , the underwater
waypoint input in step S12 , and the target depths of thecurrent underwater waypoints such that the hull 10
approaches the submarine topography 400 at each underwater waypoint on the basis of the hull dynamic model set
in step S16 . In addition , the underwater navigation route of
the underwater vehicle 100 may be simulated such that thehull 10 approaches the minimum allowable height (ha ). With
the simulation , there are obtained a new underwater navi

gation route of the underwater vehicle 100 ; that is, anunderwater navigation depth (a distance from the water

surface to the hull 10 , hereinafter, referred to as a calculated

dynamic model setting unit 56 . The hull dynamic model isalso called AUV dynamics in which the motion of the hullunderwater navigation depth ), and an underwater navigation
height ( a distance from the underwater bottom to the hull 10 ,10 (or the underwater vehicle 100 ) in the water is obtained

hereinafter, referred to as a calculated underwater navigation
height) at each underwater waypoint.
[0099 ] In step S24 , it is determined whether a distanceon the basis of calculation . Equations of motion represented
by differential equations in a time domain are a typicalexample . As a general solution , a speed and an angular speed
component as unknown quantities in the equations ofmotion

are found using a force applied to an object and a moment( calculated underwater navigation height) from the underwater bottom at each underwater waypoint in the newcomponent as inputs . In many cases, an initial condition is

given by an analytic procedure to obtain a general solution ,step S22 is larger than the minimum allowable height (ha ).

and a numerical procedure is used to obtain a time sequence

underwater navigation height confirming unit 60. In a casewhere there is an underwater waypoint where the calculated

ofspeeds and angular speeds as time passes. Specifically, thesolution is determined on the basis of response characteristics of the main propeller 12 , the vertical rudder 16 , and thehorizontal rudder 20 , and a movement characteristic of thehull 10 . When an optimum target value ( the depth and theheight) in the invention is obtained , there is used a procedureof updating the target value by a sequential method as

illustrated in FIG . 3 . However , the hull dynamic model isused as a tool for obtaining a behavior of the hull 10 (AUV )in a numerical manner by an underwater navigation simulation in the procedure . A coefficient term in the equations of
motion is a function of a fluid force operating on the hull 10 ,underwater navigation route obtained in the simulation in

In this process, the route setting device 200 serves as anunderwater navigation height is lower than the minimum
process proceeds to step S30 . In a case where there is noallowable height (ha ), the simulation is ended and theunderwater waypoint where the calculated underwater navi

gation height is lower than the minimum allowable height(ha ), the process proceeds to step S26 .
[0100 ] In step S26 , it is determined whether the counter ie

is equal to the maximum number ofrepetitions (Ne ). In thisprocess, the route setting device 200 serves as a repetition
count confirming unit 62. In a case where the counter ie isUS 2019 /0155310 A1
less than the maximum number of repetitions (Ne), theprocess proceeds to step S28 and, if not, the process pro

May 23, 2019
ever, when the speed is lowered , the vertical rudder 16 andceeds to step S30 .
10101] In step S28 , an optimization procedure is applied

the horizontal rudder 20 are degraded in effectiveness .
Further, efficiency in inspection on the underwater bottom isalso degraded , and thus there is a limitation . In addition , if

depth at each underwater waypoint . In this process , the routeon the basis of the objective function to update the target
setting device 200 serves as a target value updating unit 64 .

the control system and problems in resolution and accuracy

The objective function is set with respect to a specific target

in the navigation of the underwater vehicle 100. For

speed range for every underwater vehicle 100 .
f0106 ] In addition , in this embodiment , the objective func

example, in a case where the hull 10 is intended to submerge

tion has been set to a total sum of the depths or the heightsfrom the water surface as deep as possible , a total sum of thecalculated underwater navigation depths of the hull 10 in theentire underwater navigation route is set to the objectivefunction . Then , the processing unit 40 updates the target

value at each underwater waypoint such that the value of theobjective function is minimized . Thereafter, the processreturns to step S20 to repeat the simulation of the underwaternavigation route again using the new target value .
[0102 ] In a case where the process proceeds to step S30 ,an optimum target value (optimum target depth ) is set. In
this process , the route setting device 200 serves as an
optimum target value setting unit 66. In step S32, theprocessing unit 40 sets and outputs the current target depth
as the optimum target depth ( depicted with a black circle inthe drawing ) as illustrated in FIG . 5 . In this process, theroute setting device 200 serves as an optimum target value
output unit 68 . The optimum target depth is a target depth ateach underwater waypointto take the underwater navigation

the speed is increased excessively , there occur a limitation inat the time of observation . Therefore , there is an appropriateof the hull 10 in the entire underwater navigation route , but
the invention is not limited thereto . For example , in a casewhere the hull 10 is intended to approach a reference route(a reference depth and a reference height) as a predeterminedreference instead of approaching the underwater bottom on

the basis of the submarine topography 400 , a total sum ofabsolute values of differences between the depths of the hull
10 in the entire underwater navigation route and the reference route (the reference depth and the reference height) ora total sum of squares of the differences is set to the objectivefunction . The target value the target depth and the target

height) may be optimized on the basis of the objectivefunction .
[0107] In addition , in a case where the hull 10 is intended
to be controlled in its attitude , an attitude (for example , anangle of the hull to make the hull 10 parallel to an inclined

angle of the underwater bottom ) at each underwater way

point is set in advance as a reference . In step S28 , a total sum

route as deep from the water surface as possible whileof absolute values of differences between the attitudes

keeping the minimum allowable height (ha ) so as not to( angles of the hull) of the hull 10 in the entire underwater

come into contact with the underwater bottom when thenavigation route and the reference attitude or a total sum of

underwater vehicle 100 navigates underwater.

squares of the differences may be set to the objective

0103 ] With the above process , when a navigation controlof the underwater vehicle 100 is performed , the target depth(target depth ) at each underwater waypoint is optimized .

value at each underwater waypoint such that the value of theobjective function is minimized . Then , in a case where the

Therefore, the underwater vehicle 100 can navigate underwater in an appropriate underwater navigation route bycontrolling a motion control system of the underwater
vehicle 100 such that the target depth at each underwater

waypoint is optimized .

[ 0104 Further, in a case where the hull 10 is intended toapproach the underwater bottom as close as possible , a totalsum of the calculated underwater navigation heights of thehull 10 in the entire underwater navigation route may be set

to the objective function in step S28. Then , the processing

unit 40 updates the target value at each underwater waypointsuch that the value of the objective function is minimized .
Thereafter, the process returns to step S20 to repeat thesimulation of the underwater navigation route again using

the new target value. Then , in a case where the processproceeds to step S30, an optimum target value (optimum
target height) is set.
[0105 ] With the above process, when the navigation con

trol of the underwater vehicle 100 is performed , the target

depth at each underwater waypoint is optimized . Therefore ,the underwater vehicle 100 can navigate underwater in an

function . Then , the processing unit 40 updates the target

process proceeds to step S30 , an optimum target value is set.
[0108] < Optimum Navigation Control of Underwater
Vehicle >101091. Hereinafter, the navigation control of the underwa

ter vehicle 100 will be described on the basis of the optimum

target value which is set in the route setting process of theunderwater vehicle 100 .
[0110 ] A navigation control process is progressed along a
flowchart of FIG . 6 . The respective units of the underwater
vehicle 100 serve as the respective units illustrated in afunctional block diagram of FIG . 7 so as to realize thenavigation control.
[0111 ] In step S40 , the optimum target value (optimum

target depth ) is input and set. In this process , the control

device 34 of the underwater vehicle 100 serves as an

optimum target value input unit 70 . The optimum target

value (optimum target depth ) set by the route setting method
for the underwater vehicle 100 is input to the control device

34 through an input unit ( not illustrated ) of the control
device 34 , and is stored in a storage unit 72 of the control

device 34 . Herein , the input to the underwater vehicle 100

appropriate underwater navigation route by controlling the
motion control system of the underwater vehicle 100 suchmay be performed using an input device which is laid on thethat the target height at each underwater waypoint is opti
mized. Further, when the speed of the underwater vehicle

Further, the optimum target value is derived along a flow

100 is lowered , the inertial influence becomes smaller.

Therefore , it is considered that the underwater navigationroute may be taken deep from the water surface while
avoiding the collision with the underwater bottom . How

control device 34 , or may be performed by an externalinterface such as the acoustic communication device 36 .
chart of FIG . 3 normally by the support ship 300 or
according to an observation plan before the support ship 300
puts out to sea , and the optimum target value is input to thecontrol device 34 . However, the optimum target value mayUS 2019 /0155310 A1
be derived by performing the route setting method when the

May 23, 2019
underwater navigation . On the other hand , in a case wherecontrol device 34 of the underwater vehicle 100 starts theno obstacle is detected , the process proceeds to step S52 .

underwater navigation .

With this process, the underwater vehicle 100 serves as an(0112 ] In a case where the underwater vehicle 100 is

applied to the autonomous underwater vehicle (AUV ), theunderwater vehicle 100 may receive a predetermined opti
mum target value (optimum target depth ) and conditions
from a ship on the sea , and submerge into the sea toautonomously navigate . As a merit on the control of theunderwater vehicle 100 by inputting the predetermined

optimum target value (optimum target depth ), the underwa

ter vehicle 100 can be accurately controlled without being
affected by a delay on time taken when the underwaternavigation route is repeatedly simulated .

[0113] In step S42 , the position of the underwater vehicle

100 is measured by the inertial navigation device 32 and theacoustic communication device 36 . The control device 34

acquires the position information of the underwater vehicle
100 which is obtained by the inertial navigation device 32 .

In this process , the underwater vehicle 100 serves as a

subject vehicle motion detection unit 76 . As describedabove , the control device 34 may be configured to correct
the position information of the underwater vehicle 100
which is obtained by the inertial navigation device 32 on thebasis of the position information obtained from the acoustic

emergency surfacing determination unit 82 . Further, theemergency surfacing may be performed by a command froma ship on the sea through the acoustic communication device

36 .

[0117] In step S52, it is determined whether the hull
reaches a final underwater waypoint. The control device 34

determines whether the hull 10 reaches the final underwater

waypoint of the underwater navigation route among thepredetermined underwater waypoints. If the hull reaches the

final underwater waypoint, the process proceeds to step S54
to normally float the underwater vehicle 100 , and the underwater navigation is ended . If the hull 10 does not reach the
middle underwater waypoint, the process returns to step S44

to keep the navigation control toward the next underwater

waypoint.
0118 ] As described above, the underwater vehicle 100
can navigate along an underwater navigation route and in anunderwater navigation attitude which are appropriate to a
purpose by performing the navigation control of the underwater vehicle 100 to realize the underwater navigation route(the target values at the respective underwater waypoints )set by the route setting method for the underwater vehicle .

communication device 36 . In this process, the underwaterWith this configuration , an observation of the underwater

vehicle 100 serves as a subject vehicle position calculation
unit 78 .

FIG . 5 illustrates a diagram for describing the route setting[0114 ] In step S44 , the underwater navigation of theunderwater vehicle 100 is controlled . The control device 34

vehicle 100 can be realized in an optimum state . Further ,process of the underwater vehicle according to the embodi

ment of the invention , which is an example when the routecontrols the navigation of the underwater vehicle 100 tosetting method and the underwater vehicle 100 of thisget depths ) at the underwater waypoints from the current

resources were surveyed at Myojin knoll caldera located insequentially trace the optimum target values (optimum tar
position of the underwater vehicle 100 using the position
information acquired in step S42 . The control device 34

outputs a drive control signal, a vertical steering control
signal, and a horizontal steering control signal to the main

embodiment are applied to a real sea area. Submarine

the sea near the Izu islands of Japan in June , 2015 using theunmanned underwater vehicle “URASHIMA ” for navigation (developed by Japan Agency for Marine- Earth Scienceand Technology ) as the underwater vehicle 100 . The

propeller drive motor 14 , the vertical rudder drive motor 18 ,“ URASHIMA ” navigated in the entire underwater naviga

and the horizontal rudder drive motor 22 respectively so as
to control the driving thereof. Thus, the main propeller 12 ,the vertical rudder 16 , and the horizontal rudder 20 move toof 39 m ( a minimum setting height was 40 m ). The“URASHIMA ” is a large underwater vehicle (AUV ) having

control the behavior of the hull 10 . In addition , themotionof the hull 10 is detected by the acceleration sensor and the

gyro sensor of the inertial navigation device 32 to obtain theposition information from the behavior of the hull 10 . With
such a process , the control device 34 controls the motion of

the underwater vehicle 100 such that the hull 10 has the
optimum target values (optimum target depth ) at each underwater waypoint. In this process , the underwater vehicle 100
serves as a hull motion control unit 74 .
[0115 ] In step S46 , a necessary observation is performedby the observation sensor 30 . In other words, there is

performed , for example , the observation of the submarine

topography 400 which is the purpose of the underwaternavigation of the underwater vehicle 100 . The control device
34 may transmit an observation result to the outer side of thehull 10 through the acoustic communication device 36 . In

this process, the underwater vehicle 100 serves as an obser
vation execution unit 80 .
[0116 ] In step S48 , it is determined whether there is a needfor emergency surfacing. In a case where the obstacle sensor
28 detects an obstacle against the navigation of the underwater vehicle 100, the control device 34 causes the processproceed to step S50 to float the hull 10 urgently and ends thetion area at an average height of67 m and a minimum heightan overall length of 8 m . Assuming Myojin knoll caldera has

an extremely rugged underwater bottom which has a steep
slope of 53 degrees at maximum , the result shows that anextremely high degree of difficulty has been cleared . Whenan appropriate route point is derived , an initialdepth at eachroute point is set at 120 m above from the underwater depthof the corresponding coordinates (latitude /longitude ) , and an

appropriate depth ( optimum target value ) at each route point
is derived using the route setting method of the embodiment.
In this way , according to the route setting method for theunderwater vehicle 100 of this embodiment, it is possible toreduce the height (increase the target depth ) to an average of

67 m down to 39 m at minimum with respect to the initial
target value of 120 m . Further, it is proved that the navigation along a predetermined underwater navigation route canbe made even in the navigation of a real sea area .
INDUSTRIAL APPLICABILITY[0119 ] The invention is able to be applied to a route setting
and a navigation control of an underwater vehicle as well asa movement route and a movement control of a moving bodyaccording to a predetermined condition such as topography

data and a reference attitude. For example , the invention isUS 2019 /0155310 A1able to be applied to a movement route setting and amovement control of an airplane and a drone .

REFERENCE SIGNS LIST
0120 ) 10 : hull

[0121] 12: main propeller
0122 ] 14 : main propeller drive motor[0123 ] 14a : battery[0124 ] 16 : vertical rudder[0125 ] 18 : vertical rudder drive motor
0126 ] 20 : horizontal rudder[0127] 22 : horizontal rudder drive motor
10128 ] 24 : depth indicator[0129 ] 26 : height indicator[0130 ] 28 : obstacle sensor[0131 ] 30 : observation sensor

01321 32 : inertial navigation device

0133 ] 34 : control device[0134 ] 36 : acoustic communication device[0135 ] 38 : acoustic positioning device[0136 ] 40 : processing unit
[0137] 42: storage unit
10138 44 : input unit
[0139 ] 46 : output unit
[0140 ] 50 : initial setting unit
10141 ] 52 : underwater waypoint setting unit
[0142 ] 54 : target value setting unit
[0143 ] 56 : hull dynamic model setting unit

[0144) 58 : target value following simulation unit
10145 ] 60: underwater navigation height confirming

May 23, 20192 . The route setting method for an underwater vehicleaccording to claim 1 ,wherein the target value is a target depth on the underwater waypoint.
3 . The route setting method for an underwater vehicleaccording to claim 2 , further comprising :setting a minimum allowable height of the underwater
vehicle ,wherein , in the simulation of the underwater navigation ,a calculated underwater navigation height of the underwater vehicle with respect to the target depth is simu
lated on the basis of the dynamic model of the underwater vehicle using the data of the submarine

topography and the target depth , and the calculated

underwater navigation height and the minimum allow
able height are compared to derive the optimum target
depth .
4 . The route setting method for an underwater vehicleaccording to claim 3,
wherein , in the updating of the target value, the target
depth is updated such that a minimum value of thecalculated underwater navigation height approaches theminimum allowable height in a case where there is adifference between the minimum value of the calcu
lated underwater navigation height and the minimum

allowable height.
5 . The route setting method for an underwater vehicleaccording to claim 3 ,wherein a value of the objective function is a total sum ofabsolute values of differences between the calculated

unit

underwater navigation heights at a plurality of the101471 64 : target value updating unit

height, or a total sum of squares of the differences, and[0146] 62 : repetition count confirming unit
[0148 ) 66 : optimum target value setting unit
101491 68 : optimum target value output unit

[0150 ] 70 : optimum target value input unit

[0151] 72 : storage unit
10152 ] 74 : hull motion control unit
[0153 ] 76 : subject vehicle motion detection unit
10154 ) 78 : subject vehicle position calculation unit
[0155 ] 80 : observation execution unit
[0156 ] 82: emergency surfacing determination unit
[0157 ] 100 : underwater vehicle[0158 ] 200 : route setting device
10159 ) 300 : support ship
[0160 ] 400 : submarine topography
10161 ] 500 : satellite
1 . A route setting method for an underwater vehicle ,comprising:
inputting an underwater waypoint of an underwater
vehicle ;setting an initial target value on the underwater waypoint;
simulating an underwater navigation route of the underwater vehicle with respect to the target value on thebasis of a dynamic model of the underwater vehicle
using data of a submarine topography as a reference
and the target value ; andupdating the target value on the basis of an objectivefunction which is calculated on the basis of the underwater navigation route obtained in the simulating of theunderwater navigation ,wherein the target value is optimally derived by repeat
edly performing the simulation of the underwater navi
gation and the updating of the target value .

underwater waypoints and the minimum allowablein the updating of the target value , the target depth is
updated such that the value of the objective function isdecreased .

6 . The route setting method for an underwater vehicleaccording to claim 1 ,wherein the target value is a target height at the underwater waypoint .

7 . The route setting method for an underwater vehicleaccording to claim 6 , further comprising:setting a minimum allowable height of the underwater
vehicle,wherein , in the simulation of the underwater navigation ,a calculated underwater navigation height of the underwater vehicle with respect to the target height is simu
lated on the basis of the dynamic model of the underwater vehicle using the data of the submarine
topography and the target height, and the calculated

underwater navigation height and the minimum allow
able height are compared to derive the optimum target
height.

8 . The route setting method for an underwater vehicleaccording to claim 7 ,wherein , in the updating of the target value, the target
height is updated such that a minimum value of thecalculated underwater navigation height approaches theminimum allowable height in a case where there is adifference between the minimum value of the calcu

lated underwater navigation height and the minimum

allowable height.
9 . The route setting method for an underwater vehicleaccording to claim 7 ,US 2019 /0155310 A1

May 23, 201911

wherein a value of the objective function is a total sum of

15 . The route setting method for an underwater vehicle
wherein a reference route is used instead of the data of theabsolute values of differences between the calculated

according to claim 1 ,underwater waypoints and the minimum allowableheight, or a total sum of squares of the differences, andsubmarine topography.
16 . The route setting method for an underwater vehicleaccording to claim 1 ,wherein reference attitude angles of the underwater
vehicle at the underwater waypoint is used instead ofthe data of the submarine topography.

underwater navigation heights at a plurality of thein the updating of the target value, the target height isupdated such that the value of the objective function isdecreased.
10 . ( canceled )11 . The route setting method for an underwater vehicleaccording to claim 1 , further comprising:setting a minimum allowable height of the underwater
vehicle ,wherein , in the simulation of the underwater navigation,a calculated underwater navigation height of the underwater vehicle with respect to the target reference atti

tude is simulated on the basis of the dynamic model ofthe underwater vehicle using the data of the submarine

topography and the target reference attitude , and thecalculated underwater navigation height and the mini
mum allowable height are compared to derive theoptimum target reference attitude.

12 . The route setting method for an underwater vehicleaccording to claim 11 ,wherein , in the updating of the target value , the target
reference attitude is updated such that a minimum valueof the calculated underwater navigation heightapproaches the minimum allowable height in a casewhere there is a difference between the minimum valueof the calculated underwater navigation height and theminimum allowable height.
13 . The route setting method for an underwater vehicleaccording to claim 11,

wherein a value of the objective function is a total sum ofabsolute values of differences between the calculated

17 . An optimum control method for an underwater vehicle
comprising:
controlling the underwater vehicle using the optimum
target value obtained in the route setting method for anunderwater vehicle according to claim 1 .
18 . The optimum control method for an underwater
vehicle according to claim 17 ,wherein the optimum target value and a position of theunderwater vehicle are compared to control a motion

control system of the underwater vehicle according to

a comparison result.
19 - 20 . ( canceled )21 . An underwater vehicle, comprising:a target value acquisition unit which acquires the opti
mum target value acquired in the route setting method
for an underwater vehicle according toa storage unit which stores the acquired target value ; anda motion control unit which controls a drive unit using thetarget value stored in the storage unit .

22 . The underwater vehicle according to claim 21, further
comprising:at least one of a depth measuring unit , a heightmeasuring
unit, and a attitude measurement unit,
wherein the motion control unit compares a measurement
value of at least one of the depth measuring unit, theunderwater navigation heights at a plurality of theheight measuring unit, and the attitude measurement

underwater waypoints and the minimum allowable

control the drive unit.
23 . The underwater vehicle according to claim 21 , further

height, or a total sum of squares of the differences, andin the updating of the target value , the target reference
attitude is updated such that the value of the objectivefunction is decreased .

14 . The route setting method for an underwater vehicleaccording to claim 1 ,wherein the number of repetitions of the simulation of theunderwater navigation and the updating of the target
value is set in advance .

unit with the target value stored in the storage unit tocomprising :an obstacle detection unit ,wherein the motion control unit controls the drive unit
according to a detection result of the obstacle detectionunit.

24 - 25 . (canceled )