US011048274B2( 12 ) United States Patent( 10 ) Patent No.: US 11,048,274 B2(45 ) Date of Patent :Jun . 29 , 2021

Kim(52) U.S. CI.

( 54 ) ROUTE SETTING METHOD FOR

CPC

UNDERWATER VEHICLE , UNDERWATERVEHICLE OPTIMUM CONTROL METHODUSING SAME , AND UNDERWATERVEHICLE( 71 ) Applicant: NATIONAL INSTITUTE OF
MARITIME , PORT AND AVIATIONTECHNOLOGY, Tokyo (JP)( 72 ) Inventor: Kangsoo Kim , Tokyo (JP)(Continued )( 58 ) Field of Classification Search
CPC
G05D 1/10 ; G05D 1/048 ; GO5D 1/0875 ;B63C 11/00 ; B63C 11/48 ; B63G 8/001 ;(Continued )References Cited(56)
U.S. PATENT DOCUMENTS( 73 ) Assignee : National Institute of Maritime , Port,and Aviation Technology , Tokyo (JP)( * ) Notice : Subject to any disclaimer, the term of thispatent is extended or adjusted under 35
U.S.C. 154 ( b ) by 462 days .
15 /781,566(21 ) Appl. No .:Dec. 9 , 2016(86) PCT No .:$ 371 (c ) ( 1 ) ,( 2 ) Date :PCT / JP2016 / 086723

H04B 13/02
367/134
B63B 27/36
114/3226,390,012 B1 * 5/2002 Watt

( Continued )FOREIGN PATENT DOCUMENTS
104180804 A
63-273797

12/2014
11/1988(Continued )OTHER PUBLICATIONS

Jun . 5 , 2018

International Search Report for corresponding International Application No. PCT/ JP2016 /086723 , dated Feb. 14 , 2017 .

( 87 ) PCT Pub . No .: WO2017/099219(65 )5,894,450 A * 4/1999 Schmidt

CNJP(22) PCT Filed :G05D 1/10 (2013.01 ) ; B63C 11/00( 2013.01 ) ; B636 8/001 ( 2013.01 ) ; GOIC
21/005 (2013.01 ) ;PCT Pub . Date : Jun . 15 , 2017

( Continued )Primary Examiner Ronnie M Mancho

Prior Publication Data
US 2019/0155310 A1
May 23 , 2019(74 ) Attorney, Agent, or Firm -Jason H. Vick ; Sheridan
Ross , PC
ABSTRACT( 57 )

Foreign Application Priority Data

( 30 )

Dec. 9 , 2015 ( JP )JP2015-240252( 51 ) Int . Ci.

G06F 17700
G05D 1/10( 2019.01 )water bottom topography data and the target values on the(Continued )( 2006.01 )(Continued )36

The route setting method is provided with : an underwater
waypoint input step for inputting underwater waypoints of
the underwater vehicle ; a target value setting step for setting
initial target values at the underwater waypoints ; an underwater navigation simulation step for simulating an underwater navigation route of the underwater vehicle by using

34

28
20

32

20

22

14

12

US 11,048,274 B2
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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 thebasis 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 .

2015/0000582 A1 *1/2015 Lelaurin

B63G 8/001
114/257

2016/0046358 A1 *2/2016 Lelaurin

GOIV 1/3852
405/158
GO5D 1/0027
701/2
GOIV 1/3852

2016/0050030 A1 *2/2016 Riedl

G08C 23/02

2016/0076892 A1 *3/2016 Zhou

2016/0097875 A1 *4/2016 Kowalczyk

B64D 47/08
701/3
G05D 1/048
701/21

2016/0244135 A1 *2016/0251944 A1 *8/2016 Farber
9/2016 Carminati

B63G 8/001

2016/0253906 A1 *9/2016 Celikkol

E21B 43/36
114/321
G08C 23/00

2016/0341554 A1 * 11/2016 Hillier

701/21
GO8G 5/0013

2015/0331130 A1 * 11/2015 Henman
2015/0346722 A1 * 12/2015 Herz

114/312367/133

20 Claims , 8 Drawing Sheets(51 ) Int. Ci.
B63C 11/00
GOIC 21/20
G01C 21/00
B63G 8/00
G05D 1/04

G05D 1/08(52) U.S. Ci .
CPC

(2006.01 )( 2006.01 )( 2006.01 )( 2006.01)( 2006.01 )(2006.01 )FOREIGN PATENT DOCUMENTS

GO1C 21/20 (2013.01 ) ; GOIC 21/203

JP
JP
JP

( 2013.01 ) ; G05D 1/048 ( 2013.01 ) ; G05D
1/0875 (2013.01 ) ; B63G 2008/004 (2013.01 )JP

CPC .. B636 2008/004 ; B63G 8/00 ; G01C 21/005 ;JP( 58 ) Field of Classification Search
USPC

GO1C 21/20 ; G01C 21/203 ; GO1V 1/38 ;B63B 27/16 ; B63B 25/00 ; B63B 25/0002

JP
JP
JP
JP

701/21

See application file for complete search history .
( 56 )

References Cited

8,300,499 B2 * 10/2012 Coleman
8,305,840 B2 * 11/2012 Maguire

GOIS 15/8902
367/88GO1S 15/96

8,463,458 B2 * 6/2013 Wood
9,013,953 B2 * 4/2015 Brizard

G06T 11/206

2004/0030571 A1

2/2004 Solomon

2005/0270905 A1 * 12/2005 Patterson

367/88701/2
GOIV 1/186
367/15
GO1S 15/8902

GO1V 8/02
GOIV 1/3852
GO1S 5/183
F41H 13/00
700/248
GO1S 15/8902

367/88
2008/0300821 A1 * 12/2008 Frank

2007-292729
2008-265651 A
2013-141916

2014-121927
2015-063181

1/19935/20037/20059/2005
11/2007
11/2008
7/20137/20144/2015OTHER PUBLICATIONS

Written Opinion for corresponding International Application No.
PCT/JP2016/086723 , dated Feb. 14 , 2017 .

U.S. PATENT DOCUMENTS

9,182,486 B2 * 11/2015 Brown
9,829,602 B2 * 11/2017 Bond
9,969,470 B2 * 5/2018 Brizard
9,995,824 B2 * 6/2018 Harvey

05-016878
2003-127983
2005-193767
2005-239027

GO1V 1/201
702/150

2009/0076670 A1

3/2009 Bandyopadhyay et al .

2009/0231953 A1 *9/2009 Welker

Chen , Chen -Wei et al . “ Modeling and Simulation of an AUV
Simulator with Guidance System ” IEEE Journal of Oceanic Engi
neering , vol . 38 , No. 2 , Apr. 2013 : pp . 211-225 .

Houts, Sarah E. et al . “ Aggressive Terrain Following for Motion
Constrained AUVs” 2012 IEEE /OES Autonomous Underwater Vehicles( AUV ); XP055597332 ; Sep. 1 , 2012 ; pp . 1-7 .

Hyakudome, Tadahiro et al . “ The Experimental Results About
Maneuverability and Survey Ability of AUV “ Urashima?"" Oceans
2010 ; IEEE , Piscataway, NJ , USA ; XP031832793 ; Sep. 20 , 2010 ;pp. 1-6.

Yoerger, Dana R. , et al . “ Fine - Scale Survey in Rugged Deep - Ocean
Terrain with an Autonomous Robot” Robotics and Automation ,2000 Proceedings , ICRA '00 , IEEE International Conference; XP055597455 ; Jan. 2000 ; pp . 1787-1792 .
Yoerger, Dana R. , et al . “ Techniques for Deep Sea Near Bottom
Survey Using an Autonomous Underwater Vehicle” Robotics Research ;Springer Berlin Heidelberg , Berlin , Heidelberg; XP055597461 ; Jan.
2007 ; pp . 416-429 .
European Search Report for corresponding European Patent Application No. 16873112.3 , dated Jun . 28 , 2019 .
Notice of Reasons for Refusal ( Including Translation ) for corre
sponding Japanese Patent Application No. 2015-240252 , dated Nov.
26 , 2019 .
Chinese Office Action ( including translation ) for corresponding

2011/0313655 A1 * 12/2011 Litvack

GO1V 1/3835
367/19B63H 25/42
114/330
G01C 21/20

2012/0020185 A1 *1/2012 Welker

701/426
GOIV 1/3826

International Application No. PCT/JP2016/ 086723 , dated Jun . 21 ,2012/0143808 A1 *6/2012 Karins

367/16
GOON 7/005
706/46
B63G 8/08

Office Action for corresponding European Patent Application No.
16873112.3 , dated May 20 , 2020 .
Chinese Office Action ( including translation ) for corresponding

2011/0297070 A1 * 12/2011 Riggs

2013/0269585 A1 * 10/2013 Kim

114/3312014/0177387 A1 *6/2014 Brizard

GOIV 1/3808
367/15

2014/0301161 A1 * 10/2014 Brizard

GOIV 1/3835
367/15Chinese Application No. 2016800723050 dated Jul. 3 , 2020 .

International Preliminary Report on Patentability for corresponding

2018 .

Chinese Application No. 2016800723050 dated Sep. 12 , 2019 .

Chinese Office Action ( including translation ) for corresponding

Chinese Application No. 2016800723050 dated Dec. 21 , 2020 .
* cited by examiner

U.S. Patent

US 11,048,274 B2

Sheet 1 of 8

Jun . 29 , 2021

12

14

26

20

14a
$
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FIG
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1

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U.S. Patent

Jun . 29 , 2021

US 11,048,274 B2

Sheet 2 of 8

200
42
I

PROCESSING
UNIT

STORAGE UNIT

46
INPUT UNITOUTPUT UNIT

FIG . 2

U.S. Patent

Jun . 29 , 2021
9

Sheet 3 of 8

US 11,048,274 B2

START

S10
SET INITIAL VALUES12INPUT UNDERWATER WAYPOINTS14
SET INITIAL TARGET VALUES16
SET HULL DYNAMIC MODEL

S18

S20

S22

S28
UPDATE TARGET VALUE AT EACH
UNDERWATERWAYPOINT

SIMULATE UNDERWATER NAVIGATIONS24
IS THERE HEIGHT LOWER THANYESMINIMUM ALLOWABLE HEIGHT ( ha) ?
S26
DOES IE REACH MAXIMUM NUMBER

OF REPETITIONS ( Ne) ?

NO

S30
OPTIMUM TARGET VALUES CURRENTTARGET VALUES32OUTPUT OPTIMUM TARGET VALUEEND

FIG . 3

U.S. Patent

Jun . 29 , 2021

US 11,048,274 B2

Sheet 4 of 8

HDMYOUNALMEIC USENTITG
56

TOVPARLIGMUET SUETNITG VTOPARLIGMUET OUNTIPUVTARLGUET USENTITG

UFVTOALRGWUIENT SIMNLATIG54WUNADYEPROIT

SUENTITG

52200

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4
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FIG

UUNADVEIRGWTO CHOENFIRGMT CREOPUTIN UCONFIRMTG
62

U.S. Patent

Jun . 29 , 2021

Sheet 5 of 8

US 11,048,274 B2

1200
10 0
INRN(UO:AVDEIBGWATLOENRU:NSO()AIDVMREUGLBWATIEOTRN

TIDNAERPGITAHL DTOPAERIGMTUH

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FIG
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600
S

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400
.

200
v
0

10

120

DEPTH
m
(
)

130

140

U.S. Patent

Jun . 29 , 2021

US 11,048,274 B2

Sheet 6 of 8

S40
INPUT OPTIMUM TARGET VALUE
S42

MEASURE POSITION OF
UNDERWATER VEHICLE
S44

CONTROL TRACING OF
UNDERWATER NAVIGATION ROUTEPERFORM OBSERVATIONPROCESSS48

IS EMERGENCY SURFACING
NEEDED ?
S52

IS IT FINAL UNDERWATER

WAYPOINT ?
S50

YES

S54

FLOAT URGENTLYFLOAT NORMALLY

FIG . 6

U.S. Patent20

Jun . 29 , 2021

HORIZNTAL RUDER

MAIN
12

HROUIDZNETARL MDORTIVRE

Sheet 7 of 8

PROEL VERTICAL RUDERRVEUDTICARL MDORNITVER

MPROAEILNR MDORNITVER

7
.
FIG

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22

OBSERVATIN

US 11,048,274 B2OEXNCUITODSEUMRFAGCINY UETNRMIAOUMHOVUTEILON CONTIROL

80
14

72

PVSEUOHBIJCLET UCTALINOT N

STORAGE UNT
78

OTVPARLIGMUET IUNPIUT SVEUHBIJCLT MDUEOTNCITON
70

76

U.S. Patent

Jun . 29 , 2021

SC(AO-ONE)MTUHPNLIRCOATPEHN

US 11,048,274 B2

Sheet 8 of 8

WSUARTFEC
320

10ACOMUNIST

AUV

8
.
FIG

SUHPIORPT20

APOCSIUTNG

SUBMARINE TOPGRAHY

US 11,048,274 B2
1

2

ROUTE SETTING METHOD FOR

mation , and the underwater vehicle is controlled to navigate
in the safety region (Patent Document 5 ) .

UNDERWATER VEHICLE , UNDERWATERVEHICLE OPTIMUM CONTROL METHODUSING SAME , AND UNDERWATERVEHICLE

CITATION LIST
5

CROSS REFERENCE TO RELATEDAPPLICATIONSThis application is a national stage application under 35 10
U.S.C. 371 of PCT Application No. PCT/JP2016 /086723
having an international filing date of 9 Dec. 2016 , which
designated the United States , which PCT application
claimed the benefit of Japanese Application No. 2015 15240252 filed 9 Dec. 2015 , each of which are incorporated

herein by reference in their entirety .

Patent Literature

Patent Document 1 : JP 63-273797 A
Patent Document 2 : JP 05-016878 A
Patent Document 3 : JP 2003-127983 A
Patent Document 4 : JP 2007-292729 A
Patent Document 5 : JP 2015-063181 A

SUMMARY
Technical Problem

A reflection intensity of an inspection signal such as asonic wave is in inverse proportion to an incident angle to
20 the underwater bottom . In other words, the reflection inten
The present invention relates to a route setting method for sity is remarkably weakened compared to a normal inci
an underwater vehicle, an optimum control method for an dence ( an incident angle of “ O ” ) when the incident angle isunderwater vehicle using the same , and an underwater large at a region which is shallow with respect to thevehicle.
underwater bottom . Therefore, in a case where a submarine
25 topography has complicate ups and downs, an intensity of a
BACKGROUND
reflection signal is correlated to the topography and is weakcompared to a case where the submarine topography is flat.
In recent years, the underwater bottom is drawing atten- Further, in a complicated submarine topography the problem
tion as a supply source of all resources ranging from mineral of multipath is remarkable compared to a flat underwater
TECHNICAL FIELD

resources . Accordingly, there has been an increasing neces- 30 bottom . As a result , a height of a vehicle measured by asity for inspecting the underwater bottom . In the inspection height indicator is lowered in reliability.
of the underwater bottom , a remote sensing method using
For such a reason , a height-based vertical control of asignals such as sonic waves , lasers , visible light, and elec- vehicle is rarely employed in view of the safe navigation
tromagnetic waves is normally employed. However, since except a case where information of the height is stably
these signals suffer a propagation loss , these signals are used 35 obtained with high accuracy similarly to the flat underwaterat positions as close as possible to the underwater bottom in bottom , but a depth -based vertical control of a vehicle isorder to obtain information of high resolution and high employed in many cases .
accuracy . Therefore, there is a need for a technology that
In an actual situation , when the depth control is applied toenables an underwater vehicle ( for example , a submersible underwater vehicle navigation , a target depth is set such thatvessel ) to navigate ( sails ) on a desired route and in a desired 40 the underwater vehicle is controlled to be safe from theattitude near the underwater bottom .
bottom collision . However, a relation between a submarine
There is disclosed a technique that the underwater vehicle topography and the dynamics of an underwater vehicle isis provided with a depth setting unit to set a depth thereof, extremely difficult to be evaluated in setting the target depth .
and performs control on driving of stern steering on the basis Further, in a rough submarine topography there is a concernof a predetermined depth (Patent Document 1 ) . Herein , a 45 of bottom collision . On the other hand, when the target depth
limit circuit is provided between the depth setting unit and is set to make the underwater vehicle separated from thea depth control unit such that the underwater vehicle is underwater bottom by a sufficient distance in order to avoid
controlled so as not to come into contact with the underwater bottom collision, the quality of data obtained from thebottom .
underwater bottom and the resolution are remarkably
In relation to an automatic pilot of the underwater vehicle, 50 degraded . Therefore , in practice, the target depth is set tothere is disclosed a technique that an estimation accuracy of make the underwater vehicle appropriately separated froma dynamic state quantity is improved using a dynamic model the underwater bottom on the basis of experience andto trace a dynamic characteristic of the underwater vehicle intuition . In addition, the underwater vehicle may take ain order to estimate its dynamic state ( Patent Document 2 ) . specific attitude ( for example, an attitude parallel to the
In addition, there is disclosed a technique of controlling the 55 underwater bottom ) according to a type of sensor used in thesteering of the underwater vehicle in consideration of an inspection of the underwater bottom . In this case , it isdesirable that the underwater vehicle navigate on a routeinfluence of tidal currents ( Patent Document 3 ) .
In addition, there is a need to acquire an accurate position approximating most to the slopes of the underwater bottomof the underwater vehicle to control the navigation of the while avoiding collision with the underwater bottom .
underwater vehicle . Moreover, there is disclosed a position- 60 There is no consideration in all of Patent Documents 1 toing technique in which the depths are measured at a plurality 5 about a configuration that an underwater waypoint isof positions using a multi - beam depth sounder to specify the determined in order to obtain an optimum underwater navi
position of the underwater vehicle ( Patent Document 4 ) . gation route which can make the underwater vehicle
There is disclosed technique in which the vehicle state approach the underwater bottom while preventing collision
information such as a speed, a depth , a height, and an 65 with the underwater bottom .
attitude of the underwater vehicle is acquired, a safety region
The invention has been made in view of at least one of thefor a safe navigation is set on the basis of the state infor- above problems , and an object thereof is to provide a routeUS 11,048,274 B2
3

4

setting method for an underwater vehicle , an optimum

difference between the minimum value of the calculated

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

underwater navigation height and the minimum allowableheight.
Furthermore , a value of the objective function is prefer
controlled to navigate.
5 ably a total sum of absolute values of differences between
the calculated underwater navigation heights at a plurality of
Solution to Problem
the underwater waypoints and the minimum allowableheight, or a total sum of squares of the differences , and in the
A route setting method for an underwater vehicle accord- updating of the target value , the target height is preferably
ing to the present invention includes: inputting an underwa- 10 updated such that the value of the objective function is
ter waypoint of an underwater vehicle ; setting an initial decreased .
target value in the underwater waypoint; simulating an
Here, the target value is preferably a target reference
underwater navigation route of the underwater vehicle with attitude of the underwater vehicle at the underwater way
respect to the target value on the basis of a dynamic model point.
of the underwater vehicle using data of a submarine topog- 15 Furthermore, the route setting method for an underwater
raphy as a reference and the target value ; and updating the vehicle preferably further includes: setting a minimum
target value on the basis of an objective function which is allowable height of the underwater vehicle, and in thecalculated on the basis of the underwater navigation route simulation of the underwater navigation , a calculated underobtained in the simulating of the underwater navigation, water navigation height of the underwater vehicle with
wherein the target value is optimized by repeatedly perform- 20 respect to the target reference attitude is preferably simu
ing the simulation of the underwater navigation and the lated on the basis of the dynamic model of the underwater
updating of the target value .
vehicle using the data of the submarine topography and theHere, the target value is preferably a target depth in the target reference attitude, and the calculated underwaternavigation height and the minimum allowable height areunderwater waypoint.
Furthermore, the route setting method for an underwater 25 preferably compared to derive the optimum target reference
vehicle preferably further includes : setting a minimum attitude.
allowable height of the underwater vehicle, and in the
Furthermore, in the updating of the target value , the target
simulation of the underwater navigation , a calculated under- reference attitude is preferably updated such that a minimum
water navigation height of the underwater vehicle with value of the calculated underwater navigation heightrespect to the target depth is preferably simulated on the 30 approaches the minimum allowable height in a case wherebasis of the dynamic model of the underwater vehicle using

there is a difference between the minimum value of thethe data of the submarine topography and the target depth , calculated underwater navigation height and the minimum
and the calculated underwater navigation height and the allowable height.
minimum allowable height are preferably compared toFurthermore , a value of the objective function is preferderive the optimum target depth .
35 ably a total sum of absolute values of differences between
Furthermore, in the updating of the target value , the target the calculated underwater navigation heights at a plurality of
depth is preferably updated such that a minimum value of the underwater waypoints and the minimum allowable
the calculated underwater navigation height approaches the height, or a total sum of squares of the differences, and in theminimum allowable height in a case where there is a updating of the target value , the target reference attitude isdifference between the minimum value of the calculated 40 preferably updated such that the value of the objective

underwater navigation height and the minimum allowableheight.

function is decreased .

Furthermore, the number of repetitions of the simulation

Furthermore, a value of the objective function is prefer- of the underwater navigation and the updating of the target
ably a total sum of absolute values of differences between value is preferably set in advance .
the calculated underwater navigation heights at a plurality of 45 Furthermore, a reference route is preferably used instead
the underwater waypoints and the minimum allowable of the data of the submarine topography. In addition, aheight , or a total sum of squares of the differences, and in the reference attitude of the underwater vehicle at the underwa
updating of the target value , the target depth is preferably ter waypoint is preferably used instead of the data of the
updated such that the value of the objective function is submarine topography. Furthermore, reference attitudedecreased .
50 angles of the underwater vehicle at the underwater waypoint
Furthermore , the target value is preferably a target height are preferably used instead of the data of the submarine

topography
at the underwater waypoint.
Furthermore, the route setting method for an underwater
An optimum control method for an underwater vehicle
vehicle preferably further includes : setting a minimum according to the present invention includes controlling theallowable height of the underwater vehicle, and in the 55 underwater vehicle using the optimum target value obtained
simulation of the underwater navigation , a calculated under- in the route setting method for an underwater vehicle
water navigation height of the underwater vehicle with described above.
respect to the target height is preferably simulated on the
Furthermore , the optimum target value and a position ofbasis of the dynamic model of the underwater vehicle using the underwater vehicle are preferably compared to control athe data of the submarine topography and the target height, 60 motion control system of the underwater vehicle according
and the calculated underwater navigation height and the to a comparison result .
minimum allowable height are preferably compared toFurthermore , the underwater vehicle preferably surfaces
derive the optimum target height.
urgently in a case where the optimum target value and the
Furthermore, in the updating of the target value , the target position of the underwater vehicle deviate from a predeter
height is preferably updated such that a minimum value of 65 mined condition .
the calculated underwater navigation height approaches the
Furthermore, an observation control is preferably per
minimum allowable height in a case where there is a formed to observe a submarine topography.

US 11,048,274 B2
56

An underwater vehicle according to the present invention underwater to be the optimum target depth at the underwater
preferably includes : a target value acquisition unit which waypoint while avoiding the underwater vehicle fromacquires the optimum target value acquired in the route approaching the underwater bottom below the minimum
setting method for an underwater vehicle described above ; a 5 allowable height.
storage unit which stores the acquired target value ; and a
In addition , in the updating of the target value , the target
motion control unit which controls a drive unit using the depth is updated such that a minimum value of the calculated
underwater navigation height approaches the minimum
target value stored in the storage unit .
Here , the underwater vehicle preferably further includes: allowable height in a case where there is a difference
at least one of a depth measuring unit, a height measuring between the calculated underwater navigation height and theunit , and a attitude measurement unit, and the motion control 10 minimum allowable height. Therefore , it is possible to set
unit preferably compares a measurement value of at least the optimum target depth such that the underwater vehicle
one of the depth measuring unit , the height measuring unit, approaches the underwater bottom as close as possible at theand the attitude measurement unit with the target value underwater waypoint while avoiding the underwater vehicle
from approaching the underwater bottom below the mini
stored in the storage unit to control the drive unit .

Furthermore, the underwater vehicle preferably further 15 mum allowable height .

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.

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

Furthermore, the underwater vehicle preferably further waypoints and the minimum allowable height, or a total sum
includes : an inertial navigation unit, and the motion control 20 of squares of the differences. In the updating of the target
unit preferably controls the drive unit on the basis of an value, the target depth is updated such that the objectivefunction is decreased . Therefore, it is possible to set theoutput of the inertial navigation unit .
Furthermore, the underwater vehicle preferably further optimum target depths at the plurality of underwater way
includes : an observation unit which observes a submarine points such that a total sum of absolute values of differences
topography.
25 between the calculated underwater navigation heights at theplurality of underwater waypoints and the minimum allow
Advantageous Effects of Invention
able height, or a total sum of squares of the differences isminimized .
A route setting method for an underwater vehicle accordIn addition, the target value is a target height at theing to claim 1 includes inputting an underwater waypoint of 30 underwater waypoint. Therefore, it is possible to set an
an underwater vehicle, setting an initial target value in the optimum target height which is optimized to the submarine
underwater waypoint, simulating an underwater navigation topography at the underwater waypoint. With this configu
route of the underwater vehicle with respect to the target ration , the underwater vehicle can navigate to be the opti
value on the basis of a dynamic model of the underwater mum target height at the underwater waypoint. Further, it isvehicle and the data of a submarine topography as a refer- 35 possible to set a route which can realize the navigation of theence and the target value , and updating the target value on optimum underwater navigation height according to a pur
the basis of an objective function which is calculated on the pose such as observation .
basis of the underwater navigation route obtained in the
In addition , the route setting method for an underwater
simulation of the underwater navigation. The target value is vehicle includes setting a minimum allowable height of the
optimized by repeatedly performing the simulation of the 40 underwater vehicle. In the simulation of the underwater
underwater navigation and the updating of the target value . navigation , a calculated underwater navigation height of the
Therefore , it is possible to set an optimum target value which underwater vehicle with respect to the target height is

is optimized to the submarine topography at the underwater simulated on the basis of the dynamic model of the under
waypoint. With this configuration, the underwater vehicle water vehicle using the data of the submarine topography
can navigate underwater with an optimum target value at the 45 and the target height, and the calculated underwater navi
underwater waypoint. Further, it is possible to set a route gation height and the minimum allowable height are com
which can realize the navigation in an optimum navigation pared to derive the optimum target height. Therefore, it isstate according to a purpose.
possible to set a route in which the underwater vehicle
Herein , the target value is a target depth at the underwater navigates underwater to be the optimum height at the
waypoint. Therefore, it is possible to set an optimum target 50 underwater waypoint while avoiding the underwater vehicle
depth which is optimized to the submarine topography at the from approaching the underwater bottom below the mini
underwater waypoint. With this configuration, the underwa- mum allowable height.
ter vehicle can navigate to be the optimum target depth at theIn addition , in the updating of the target value , the target
underwater waypoint. Further, it is possible to set a route height is updated such that a minimum value of the calcu
which can realize the navigation of the optimum depth 55 lated underwater navigation height approaches the minimum
according to a purpose such as observation .
allowable height in a case where there is a difference
In addition , the route setting method for an underwater between the calculated underwater navigation height and thevehicle includes setting a minimum allowable height of theunderwater vehicle . In the simulation of the underwater

minimum allowable height. Therefore, it is possible to set
the optimum target height such that the underwater vehicle

navigation , a calculated underwater navigation height of the 60 approaches the underwater bottom as close as possible at theunderwater vehicle with respect to the target depth is simu- underwater waypoint while avoiding the underwater vehicle
lated on the basis of the dynamic model of the underwater from approaching the underwater bottom below the minivehicle using the data of the submarine topography and the mum allowable height.
target depth , and the calculated underwater navigation
In addition , the objective function is a total sum ofheight and the minimum allowable height are compared to 65 absolute values of differences between the calculated underderive the optimum target depth . Therefore, it is possible to water navigation heights at a plurality of the underwater
set a route in which the underwater vehicle navigates waypoints and the minimum allowable height, or a total sumUS 11,048,274 B2
7

8

of squares of the differences. In the updating of the target the underwater vehicle approaches the reference route or thevalue , the target height is updated such that the objective reference attitude angles at the underwater waypoint.
function is decreased . Therefore , it is possible to set theAn optimum control method for an underwater vehicle
optimum target heights at the plurality of underwater way- according to the present invention preferably controls thepoints such that a total sum of absolute values of differences 5 underwater vehicle using the optimum target value obtained
between the calculated underwater navigation heights at the in the route setting method for the underwater vehicle .
plurality of underwater waypoints and the minimum allow Therefore, it is possible that the underwater vehicle naviable height, or a total sum of squares of the differences is gates underwaterwith the optimum target value which isminimized .
optimizedtothesubmarine
topography at the underwater
Herein , the target value is a target reference attitude of the 10 waypoint. Further, it is possible
to set a route which canunderwater vehicle at the underwater waypoint. Therefore, it realize the navigation in an optimum
navigation stateis possible to set an optimum target reference attitude which according to a purpose.
is optimized to the submarine topography at the underwater
Herein , the optimum target value and a position of the
waypoint. With this configuration, the underwater vehicle
can navigate to be the optimum target reference attitude at 15 underwater
vehicle are compared to control a motion control
the underwater waypoint. Further, it is possible to set a route system of the underwater vehicle according to a comparison
which can realize the navigation of the optimum underwater result. Therefore, it is possible to specifically realize thenavigation attitude according to a purpose such as observa optimum control method for the underwater vehicle .
tion .

In addition , the underwater vehicle urgently in a caseIn addition, in the simulating of the underwater naviga- 20 where the optimum target value and the position of thetion, a calculated underwater navigation height of the under- underwater vehicle deviate from a predetermined condition .
water vehicle with respect to the target reference attitude is Therefore, it is possible to avoid a risk such as a case where
simulated on the basis of the dynamic model of the under- the underwater vehicle is about to collide with an obstacle .
water vehicle using the data of the submarine topography
In addition , an observation control is performed toand the target reference attitude, and the calculated under- 25 observe a submarine topography. Therefore, it is possible towater navigation height and the minimum allowable height perform observation while navigating in the underwater
are compared to derive the optimum target reference atti navigation state which is appropriate to the observation .
tude. Therefore, it is possible to set a route in which theAn underwater vehicle according to the present invention
underwater vehicle navigates underwater to be the optimum preferably
a target value acquisition unit whichtarget reference attitude at the underwater waypoint while 30 acquires theincludes
optimum
value acquired in the route
avoiding the underwater vehicle from approaching the setting method for the target
underwater
vehicle , a storage unit
underwater bottom below the minimum allowable height.
stores the acquired target value , and a motion control
In additi in the updating of the target value , the target which
which controls a drive unit using the target value storedreference attitude is updated such that a minimum value of unit
in the storage unit . Therefore, it is possible to perform thethe calculated underwater navigation height approaches the 35 underwaterwith the optimum target value which
minimum allowable height in a case where there is a is optimizednavigation
to the submarine topography at the underwater
difference between the minimum value of the calculated
underwater navigation height and the minimum allowable waypoint. Further, it is possible to set a route which canheight. Therefore, it is possible to set the optimum target realize the navigation in an optimum navigation statereference attitude such that the underwater vehicle 40 according to a purpose.
approaches the underwater bottom as close as possible at thefrom approaching the underwater bottom below the mini-

Herein , the underwater vehicle includes at least one of a
attitude measurement unit . The motion control unit com
mum allowable height.
pares a measurement value of at least one of the depth
In addition , a value of the objective function is a total sum 45 measuring unit , the height measuring unit , and the attitude
of absolute values of differences between the calculated measurement unit with the target value stored in the storage

underwater waypoint while avoiding the underwater vehicle

depth measuring unit , a height measuring unit, and anunderwater navigation heights at a plurality of the under- unit to control the drive unit . Therefore, it is possible towater waypoints and the minimum allowable height, or a specifically realize the optimum control method for the
total sum of squares of the differences . In the updating of the underwater vehicle which obtains the optimum target value .
target value , the target reference attitude is updated such that 50 In addition, the underwater vehicle includes an obstacle
the value of the objective function is decreased . Therefore , detection unit . The motion control unit controls the drive
it is possible to set the optimum target reference attitude at unit according to a detection result of the obstacle detection
the plurality of underwater waypoints such that a total sum unit. Therefore, it is possible to avoid a risk such as a caseof absolute values of differences between the calculated where the underwater vehicle is about to collide with anunderwater navigation heights at the plurality of underwater 55 obstacle .
waypoints and the minimum allowable height, or a total sum
In addition , the underwater vehicle includes an inertial
navigation unit. The motion control unit controls the driveof squares of the differences is minimized .
In addition, the number of repetitions of the simulating of unit on the basis of an output of the inertial navigation unit.
the underwater navigation and the updating of the target Therefore, it is possible to set the optimum target value
value is set in advance. Therefore, it is possible to complete 60 which is optimized to the submarine topography at thean underwater navigation simulation an appropriate number underwater waypoint only by the subject vehicle withoutof times .

In addition , a reference route is used instead of the data ofacquiring the position information from the outer side .

In addition , the underwater vehicle includes an observa

the submarine topography. Alternatively, reference attitude tion unit which observes a submarine topography. Therefore ,angles of the underwater vehicle in the underwater waypoint 65 it is possible to perform observation while navigating in theare used instead of the data of the submarine topography. underwater navigation state which is appropriate to the
Therefore, it is possible to optimize the target value such that observation .

US 11,048,274 B2
109BRIEF DESCRIPTION OF DRAWINGS

position detection unit, a control device 34 , an acoustic
communication device 36 , and an acoustic positioning
FIG . 1 is a conceptual diagram illustrating a configuration device 38. The underwater vehicle 100 is , for example , anof an underwater vehicle according to an embodiment of the 5 autonomous underwater vehicle ( AUV ) , but the invention isinvention .

FIG . 2 is a diagram illustrating a configuration of a routesetting device of the underwater vehicle according to theembodiment of the invention .

FIG . 3 is a flowchart of a route setting method for theunderwater vehicle according to the embodiment of the 10
invention .

not limited thereto .

The hull 10 is a sealable structure which makes spaces
such as cabins . The hull 10 is configured by a metal orreinforced plastic material, and also serves to mechanicallysupport components of the underwater vehicle 100 .

The main propeller 12 is a component which generates adriving force to propel the underwater vehicle 100. The main
propeller 12 is configured by a propeller and a rotation shaft,for example. The main propeller drive motor 14 is a motor

FIG . 4 is a functional block diagram of the route setting
device of the underwater vehicle according to the embodi
ment of the invention .
FIG . 5 is a diagram for describing a route setting process 15 to apply the driving force to the main propeller 12. The main
propeller drive motor 14 receives a drive control signal fromof the underwater vehicle according to the embodiment of thecontrol device 34 to rotatably drive the rotation shaft of
the invention .
FIG . 6 is a flowchart of an optimum navigation control of the main propeller 12 by power from a battery 14a at thethe underwater vehicle according to the embodiment of the rotation number and torque according to the drive control
20 signal. With this configuration , the propeller connected toinvention .
FIG . 7 is a functional block diagram of the underwater the drive shaft is rotated , and applies a propulsive force tovehicle according to the embodiment of the invention .
the underwater vehicle 100 .
FIG . 8 is a diagram illustrating an observation system of
The vertical rudder 16 is a rudder to turn (revolve) the hulla submarine topography using the underwater vehicle 10 in the right and left direction . The hull 10 can be revolved
25 to the left or right side by inclining the vertical rudder 16 toaccording to the embodiment of the invention .
the right or left side with respect to the hull 10. The vertical
DESCRIPTION OF EMBODIMENTS
rudder drive motor 18 is a motor to generate a driving force
to rotate the vertical rudder 16. The vertical rudder drive< System Configuration >motor 18 receives a vertical steering control signal from the

FIG . 8 is a diagram illustrating an observation system of 30 control device 34 to rotatably drive the vertical rudder 16 toa submarine topography using an underwater vehicle form attitude angles corresponding to the vertical steering

according to an embodiment of the invention . The observa- control signal.
tion system is configured by an underwater vehicle 100
Fur the hull 10 may be configured to turn ( revolve) inwhich submerges into the water, a route setting device 200 , the right and left direction such that the main propellers 12
and a support ship 300 on the water, on which the route 35 are individually provided on the right and left sides tosetting device is mounted . The underwater vehicle 100 balance the propulsive force of the right and left mainnavigates along an optimum underwater navigation route propellers 12 without depending on the vertical rudder 16 .
which is set to make a closest approach to the underwater

The horizontal rudder 20 is a rudder to raise and fall thebottom while preventing collision in order to observe a hull 10. The hull 10 can pitch up or down by inclining up or
submarine topography 400 at an underwater waypoint. The 40 down the horizontal rudder 20 with respect to the hull 10 .
support ship 300 receives a GPS signal from a satellite 500 The horizontal rudder drive motor 22 is a motor to generate
to determine its own geographical position . Therefore , a a driving force to rotate the horizontal rudder 20. The
geographical position of the underwater vehicle 100 can be horizontal rudder drive motor 22 receives a horizontal
known. In the support ship 300 , an acoustic positioning steering control signal from the control device 34 to rotat
device 310 is mounted, so that a relative position of the 45 ably drive the horizontal rudder 20 to form attitude angles
underwater vehicle 100 in the water from the support ship corresponding to the horizontal steering control signal.
300 can be ascertained . In addition, the underwater vehicle
The depth indicator 24 is a device which measures a
100 can detect the relative position to the support ship 300 distance (depth ) from the water surface of the underwaterusing a position detection unit mounted in the underwater vehicle 100 and outputs the distance . The depth indicator 24

vehicle 100. The support ship 300 and the underwater 50 measures a depth from a water pressure applied to the hullvehicle 100 both can ascertain the relative position throughan acoustic communication device 320. Therefore, the geographical position of the underwater vehicle 100 can be

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 whichascertained in the support ship 300 and / or the underwatermeasures a distance (height) from the underwater bottom toposition detection unit of the underwater vehicle 100 .
< Configuration of Underwater Vehicle >of a time taken until the sonic waves reflected on thesensor 30 , an inertial navigation device 32 which is athereto on the basis of a time taken until the sonic waves

vehicle 100 by combining the geographical position 55 the underwater vehicle 100 , and outputs the distance . The
obtained in the support ship 300 and the relative position height indicator 26 outputs sonic waves to the lower side ofobtained in the acoustic positioning device 310 or the the hull 10 for example, and measures the height on the basis

underwater bottom are received . The height indicator 26
As illustrated in a conceptual diagram of FIG . 1 , the 60 outputs the measured height to the control device 34 .
underwater vehicle 100 according to the embodiment of the
The obstacle sensor 28 is a sensor to detect an obstacle
invention is configured by a hull 10 , a main propeller 12 , a which exists in an advancing direction ( front side ) of themain propeller drive motor 14 , a vertical rudder 16 , a underwater vehicle 100. The obstacle sensor 28 outputs thevertical rudder drive motor 18 , a horizontal rudder 20 , a sonic waves to the front side (or in a slightly lower direction
horizontal rudder drive motor 22 , a depth indicator 24 , a 65 on the front side) of the hull 10 , for example. The obstacleheight indicator 26 , an obstacle sensor 28 , an observation sensor measures the presence of an obstacle and a distanceUS 11,048,274 B2
11reflected on the obstacle on the front side are received . The

obstacle sensor 28 outputs a detection result of the obstacle

12larger than a predetermined value . The inertial navigation

device 32 keeps estimating the position of the underwater
vehicle 100 using the corrected position as a new initial
The observation sensor 30 is a sensor for the observation value .
of the underwater vehicle 100. The observation sensor 30 5 <Route Setting Method for Underwater Vehicle >may be configured by various sensors according to the
A route setting process of the underwater vehicle 100
purpose of the observation . The observation sensor 30 may according to this embodiment will be described below. In
be configured by a sonic wave sensor, an electromagnetic this embodiment, the description will be given about a casewave sensor, an optical sensor, a pressure sensor, and a where the route setting is performed by the route setting
thermal sensor, for example. The observation sensor 30 10 device 200 separated from the underwater vehicle 100. In
outputs an observed result to the control device 34 .
this case , the invention is not limited to the above configu
The inertial navigation device 32 includes an acceleration ration , and the route setting device 200 may be mounted into the control device 34 .

sensor and a gyro sensor which measure an acceleration
when the hull 10 moves . Position information of the hull 10

the underwater vehicle 100 .
As illustrated in FIG . 2 , the route setting device 200 is a

is obtained by twice integrating the accelerations measured 15 computer which includes a processing unit 40 , a storage unit

by these sensors with respect to time . The position infor- 42 , an input unit 44 , and an output unit 46. The processing
mation of the underwater vehicle 100 obtained by the unit 40 is configured by a CPU . The processing unit 40
performs the route setting process ( described below ) by
control device 34 is output to the control device 34 .
The control device 34 receives information from the depth executing a route setting program which is stored in theindicator 24 , the height indicator 26 , the obstacle sensor 28 , 20 storage unit 42 in advance. The storage unit 42 is a storage
the observation sensor 30 , and the inertial navigation device device to store the route setting program , a hull motion
32 , and controls the navigation of the underwater vehicle calculation model , and various types of data. The storage
100 on the basis of the information . The control device 34 unit 42 may be a semiconductor memory and a hard disk , forcontrols the main propeller 12 , the vertical rudder drive example. The input unit 44 includes a device which inputs
motor 18 , and the horizontal rudder drive motor 22 on the 25 information to the route setting device 200 to perform thebasis of the position information from the inertial navigation route setting process . The input unit 44 may be a keyboard ,device 32 , the depth from the depth indicator 24 , and height a mouse , and a touch panel. In addition, the input unit 44
information from the height indicator 26. Therefore, the hull may acquire information from other devices through a
10 approaches a predetermined underwater waypoint and a network interface . The output unit 46 includes a device totarget value (a target depth, a target height, a target attitude, 30 output information of a route obtained by the route setting
a target attitude angle, etc. ) which is set by a route setting device 200. The output unit 46 may be a display and amethod ( described below ) . Navigation control of the control printer. In addition, information may be output to the control
device 34 will be described below.

device 34 of the underwater vehicle 100 through the output

The acoustic communication device 36 is a device which unit 46 as the network interface.
communicates with the outer side of the underwater vehicle 35 The route setting process is performed along a flowchart

100 through the sonic waves . The acoustic communication of FIG . 3. The route setting device 200 serves as therespective units illustrated in a functional block diagram ofnavigation from the control device 34 which are measured FIG . 4 by executing the route setting process .
by the depth indicator 24 , the height indicator 26 , theIn step S10 , an initial setting is performed . In this process ,obstacle sensor 28 , the observation sensor 30 , and the 40 the route setting device 200 serves as an initial setting unit
inertial navigation device 32. The acoustic communication 50. In the initial setting, information of the submarine
device 36 transmits the information to the outer side of the topography 400 is input, the maximum number of repeti
underwater vehicle 100 ( for example, a ship on the sea) . In tions (Ne ) is set, and a minimum allowable height (ha) is set
addition, the acoustic communication device receives an as a reference using the input unit 44. The information of theabsolute position which is measured by a GPS in the outer 45 submarine topography 400 is information indicating a heightof topography at every coordinate of the underwater bottomside ( for example, a ship on the sea ) .
The acoustic positioning device 38 receives the relative in a navigation target region of the underwater vehicle 100
position between the underwater vehicle 100 and a ship on as illustrated with a thick solid line of FIG . 5. The maximum
the outer side. When being provided in a ship on the sea , the number of repetitions (Ne) is a maximum number of rep
acoustic positioning device 38 acquires information of the 50 etitions in the route setting process. The minimum allowable
relative position of the underwater vehicle 100. The relative height ( ha ) is a minimum allowable height from the underdevice 36 receives information about the results and theposition information is input to the control device 34. The
control device 34 acquires information of an absolute posi-

water bottom to set a route so that the underwater vehicle
100 does not come into contact with the underwater bottom .

underwater vehicle 100. The control device 34 can correct
the position information acquired from the inertial naviga-

coordinates on a navigation route of the underwater vehicle
100 in a plane ( the water surface; a surface parallel to the sea

tion of the ship on the sea which is acquired by the acoustic
In step S12 , an input process of the underwater waypoint
communication device 36. The control device can obtain an 55 is performed . In this process, the route setting device 200
absolute position of the underwater vehicle 100 from the serves as an underwater waypoint setting unit 52. The
absolute position of the ship and the relative position of the underwater waypoints are information indicated by discretetion device 32 using the absolute position information of the 60 surface ). In other words , the underwater waypoints areunderwater vehicle 100 thus acquired. For example, the sequentially connected to obtain a two - dimensional naviga
control device 34 corrects the position of the inertial navi- tion route of the underwater vehicle 100. The underwater
gation device 32 using the position of the acoustic position- waypoints are set according to an entire underwater navi
ing device 38 in a case where a difference between the gation route plan based on an observation plan in advance .
position calculated from the relative position information 65 In step S14 , initial target values at the respective underacquired from the acoustic positioning device 38 and the water waypoints are set . In this process, the route setting
position acquired from the inertial navigation device 32 is device 200 serves as a target value setting unit 54. In thisUS 11,048,274 B2
13

14

embodiment, the target value is a target depth of the underwater vehicle 100. In other words , as illustrated in FIG . 5 , an

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

processing unit 40 simulates the underwater navigation routewith the underwater bottom when the underwater vehicle

initial value ( illustrated as a white triangle in the drawing) ofa target depth of the underwater navigation route of theunderwater
vehicle 100 is set for every the underwater 5 underwater navigation depth ), and an underwater navigation
waypoint which is input in step S12 .
height (a distance from the underwater bottom to the hull 10 ,In step S16 , the hull dynamic model is set. In this process , hereinafter, referred to as a calculated underwater navigation
the route setting device 200 serves as a hull dynamic model height) at each underwater waypoint.
setting unit 56. The hull dynamic model is also called AUV
In step S24 , it is determined whether a distance (calcu
dynamics
in
which
the
motion
of
the
hull
10
(
or
the
10
lated
underwater navigation height) from the underwater
underwater vehicle 100 ) in the water is obtained on the basis bottom at each underwater waypoint in the new underwaterof calculation . Equations of motion represented by differ navigation route obtained in the simulation in step S22 isential equations in a time domain are a typical example. Asa general solution, a speed and an angular speed component larger than the minimum allowable height (ha ). In thisas unknown quantities in the equations of motion are found 15 process, the route setting device 200 serves as an underwaterusing a force applied to an object and a moment component navigation height confirming unit 60. In a case where there
is an underwater waypoint where the calculated underwater
as inputs. In many cases , an initial condition is given by an navigation
height is lower than the minimum allowable
analytic procedure to obtain a general solution, and aheight(ha),
the simulation is ended and the process proceeds
numerical procedure is used to obtain a time sequence of
speeds and angular speeds as time passes . Specifically , the 20 to step S30 . In a case where there is no underwater waypoint
solution is determined on the basis of response characteris- where the calculated underwater navigation height is lower
tics of the main propeller 12 , the vertical rudder 16 , and the than the minimum allowable height (ha ), the process pro
horizontal rudder 20 , and a movement characteristic of the ceeds to step S26 .
hull 10. When an optimum target value (the depth and the
In step S26 , it is determined whether the counter ie isheight) in the invention is obtained, there is used a procedure 25 equal to the maximum number of repetitions (Ne ) . In thisof updating the target value by a sequential method as process, the route setting device 200 serves as a repetition
illustrated in FIG . 3. However, the hull dynamic model is count confirming unit 62. In a case where the counter ie isused as a tool for obtaining a behavior of the hull 10 ( AUV ) less than the maximum number of repetitions (Ne) , thein a numerical manner by an underwater navigation simu- process proceeds to step S28 and , if not , the process pro
lation in the procedure. A coefficient term in the equations of 30 ceeds to step S30 .
motion is a function of a fluid force operating on the hull 10 ,In step S28 , an optimization procedure is applied on theand is frequently called a hydrodynamic coefficient. The basis of the objective function to update the target depth athydrodynamic coefficient can be obtained by a tank test each underwater waypoint. In this process , the route setting
using a scale model of the hull or a numerical calculation device 200 serves as a target value updating unit 64. The
using a procedure of a computational fluid dynamics. In the 35 objective function is set with respect to a specific target inequations of motion , items other than the hydrodynamic the navigation of the underwater vehicle 100. For example,
coefficient are variables and an external force item , so that in a case where the hull 10 is intended to submerge from thethe equations of motion are completed by obtaining the water surface as deep as possible , a total sum of thehydrodynamic coefficient.
calculated underwater navigation depths of the hull 10 in the
In steps S18 to S32 , there are performed the underwater 40 entire underwater navigation route is set to the objective
navigation simulation in which the underwater navigation function . Then, the processing unit 40 updates the target
route of the underwater vehicle 100 with respect to the target value at each underwater waypoint such that the value of thevalue is simulated on the basis of the dynamic model of the objective function is minimized . Thereafter, the process
underwater vehicle 100 using data and the target depth of the returns to step S20 to repeat the simulation of the underwatersubmarine topography 400 , and an optimization analysis in 45 navigation route again using the new target value .
which a target value updating process is repeatedly perIn a case where the process proceeds to step S30 , anformed to update the target depth and the target value (target optimum target value ( optimum target depth ) is set . In thisdepth ) at the underwater waypoint is optimized on the basis process, the route setting device 200 serves as an optimumof an objective function which is calculated on the basis of target value setting unit 66. In step S32 , the processing unit
the underwater navigation route obtained in the underwater 50 40 sets and outputs the current target depth as the optimum
navigation simulation .
target depth ( depicted with a black circle in the drawing) as
In step S18 , a counter ie is set to an initial value “ o . ” The illustrated in FIG . 5. In this process , the route setting device
counter ie is used to count the number of repetitions of the 200 serves as an optimum target value output unit 68. The
simulation . In step S20 , “ 1 ” is added to the counter ie .
optimum target depth is a target depth at each underwater
In step S22 , the underwater navigation simulation is 55 waypoint to take the underwater navigation route as deep
performed . In this process , the route setting device 200 from the water surface as possible while keeping the mini
serves as a target value following simulation unit 58. The mum allowable height (ha) so as not to come into contactof the underwater vehicle 100 using the information of the 100 navigates underwater.
submarine topography 400 input in step S10 , the underwater 60 With the above process , when a navigation control of the

waypoint input in step S12 , and the target depths of the underwater vehicle 100 is performed , the target depth (target
current underwater waypoints such that the hull 10 depth ) at each underwater waypoint is optimized . Therefore ,approaches the submarine topography 400 at each under- the underwater vehicle 100 can navigate underwater in an
water waypoint on the basis of the hull dynamic model set appropriate underwater navigation route by controlling a
in step S16 . In addition, the underwater navigation route of 65 motion control system of the underwater vehicle 100 suchthe underwater vehicle 100 may be simulated such that thehull 10 approaches the minimum allowable height ( ha ). With

that the target depth at each underwater waypoint is opti
mized .

US 11,048,274 B2
15

16

Further, in a case where the hull 10 is intended toapproach the underwater bottom as close as possible , a total

vehicle 100 serve as the respective units illustrated in afunctional block diagram of FIG . 7 so as to realize thesum of the calculated underwater navigation heights of the navigation control.
In step S40 , the optimum target value ( optimum target
hull 10 in the entire underwater navigation route may be set
to the objective function in step S28 . Then , the processing 5 depth) is input and set. In this process , the control device 34
unit 40 updates the target value at each underwater waypoint of the underwater vehicle 100 serves as an optimum target
such that the value of the objective function is minimized . value input unit 70. The optimum target value ( optimum
Thereafter, the process returns to step S20 to repeat the target depth ) set by the route setting method for the undervehicle 100 is input to the control device 34 throughsimulation of the underwater navigation route again using water
input unit (not illustrated ) of the control device 34 , andthe new target value . Then, in a case where the process 10 isanstored
storage unit 72 of the control device 34. Herein ,proceeds to step S30 , an optimum target value ( optimum the inputintoa theunderwater vehicle 100 may be performed
target height) is set.
using
an
input
deviceis laid on the control device 34 ,With the above process , when the navigation control of or may be performedwhichby an external interface such as thethe underwater vehicle 100 is performed , the target depth at 15 acoustic communication device 36. Further, the optimum
each underwater waypoint is optimized . Therefore , the target value is derived along a flowchart of FIG . 3 normally
underwater vehicle 100 can navigate underwater in an by the support ship 300 or according to an observation plan
appropriate underwater navigation route by controlling the before the support ship 300 puts out to sea , and the optimum
motion control system of the underwater vehicle 100 such target value is input to the control device 34. However, thethat the target height at each underwater waypoint is opti- 20 optimum target value may be derived by performing themized . Further, when the speed of the underwater vehicle route setting method when the control device 34 of the
100 is lowered, the inertial influence becomes smaller. underwater vehicle 100 starts the underwater navigation .
Therefore , it is considered that the underwater navigation
In a case where the underwater vehicle 100 is applied toroute may be taken deep from the water surface while the autonomous underwater vehicle (AUV ), the underwater
avoiding the collision with the underwater bottom . How- 25 vehicle 100 may receive a predetermined optimum target
ever, when the speed is lowered , the vertical rudder 16 and value ( optimum target depth ) and conditions from a ship on
the horizontal rudder 20 are degraded in effectiveness. the sea , and submerge into the sea to autonomously navigate.
Further, efficiency in inspection on the underwater bottom is As a merit on the control of the underwater vehicle 100 byalso degraded, and thus there is a limitation . In addition, if inputting the predetermined optimum target value ( optimum
the speed is increased excessively, there occur a limitation in 30 target depth ), the underwater vehicle 100 can be accurately
the control system and problems in resolution and accuracy controlled without being affected by a delay on time taken

at the time of observation. Therefore, there is an appropriate
speed range for every underwater vehicle 100 .

when the underwater navigation route is repeatedly simu
lated .

In addition, in this embodiment, the objective function has
In step S42 , the position of the underwater vehicle 100 is
been set to a total sum of the depths or the heights of the hull 35 measured by the inertial navigation device 32 and the
10 in the entire underwater navigation route , but the inven- acoustic communication device 36. The control device 34
tion is not limited thereto . For example , in a case where the acquires the position information of the underwater vehicle
hull 10 is intended to approach a reference route (a reference 100 which is obtained by the inertial navigation device 32 .

depth and a reference height) as a predetermined reference In this process , the underwater vehicle 100 serves as aof the submarine topography 400 , a total sum of absolute above , the control device 34 may be configured to correct
values of differences between the depths of the hull 10 in the the position information of the underwater vehicle 100
entire underwater navigation route and the reference route which is obtained by the inertial navigation device 32 on the( the reference depth and the reference height) or a total sum basis of the position information obtained from the acoustic
of squares of the differences is set to the objective function . 45 communication device 36. In this process, the underwater
The target value (the target depth and the target height) may vehicle 100 serves as a subject vehicle position calculation
unit 78 .
be optimized on the basis of the objective function .
In addition, in a case where the hull 10 is intended to be
In step S44 , the underwater navigation of the underwater
controlled in its attitude, an attitude ( for example , an angle vehicle 100 is controlled . The control device 34 controls theof the hull to make the hull 10 parallel to an inclined angle 50 navigation of the underwater vehicle 100 to sequentiallyof the underwater bottom ) at each underwater waypoint is trace the optimum target values ( optimum target depths) at
set in advance as a reference. In step S28 , a total sum of the underwater waypoints from the current position of theabsolute values of differences between the attitudes ( angles underwater vehicle 100 using the position informationof the hull) of the hull 10 in the entire underwater navigation acquired in step S42 . The control device 34 outputs a drive
route and the reference attitude or a total sum of squares of 55 control signal , a vertical steering control signal, and athe differences may be set to the objective function. Then , horizontal steering control signal to the main propeller drive
the processing unit 40 updates the target value at each motor 14 , the vertical rudder drive motor 18 , and theunderwater waypoint such that the value of the objective horizontal rudder drive motor 22 respectively so as tofunction is minimized . Then , in a case where the process control the driving thereof. Thus, the main propeller 12 , theproceeds to step S30 , an optimum target value is set .
60 vertical rudder 16 , and the horizontal rudder 20 move to< Optimum Navigation Control of Underwater Vehicle >control the behavior of the hull 10. In addition, the motion
Hereinafter, the navigation control of the underwater of the hull 10 is detected by the acceleration sensor and thevehicle 100 will be described on the basis of the optimum gyro sensor of the inertial navigation device 32 to obtain thetarget value which is set in the route setting process of the position information from the behavior of the hull 10. With

instead of approaching the underwater bottom on the basis 40 subject vehicle motion detection unit 76. As describedunderwater vehicle 100 .

A navigation control process is progressed along a flow-

chart of FIG . 6. The respective units of the underwater

65 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 underUS 11,048,274 B2
18

17

water waypoint. In this process , the underwater vehicle 100

underwater vehicle 100 of this embodiment, it is possible toreduce the height ( increase the target depth ) to an average ofIn step S46 , a necessary observation is performed by the 67 m down to 39 m at minimum with respect to the initialobservation sensor 30. In other words, there is performed , target value of 120 m . Further, it is proved that the naviga
for example , the observation of the submarine topography 5 tion along a predetermined underwater navigation route canserves as a hull motion control unit 74 .

400 which is the purpose of the underwater navigation of theunderwater vehicle 100. The control device 34 may transmit
an observation result to the outer side of the hull 10 throughthe acoustic communication device 36. In this process , theunderwater vehicle 100 serves as an observation execution 10
unit 80 .

be made even in the navigation of a real sea area .
INDUSTRIAL APPLICABILITY

The invention is able to be applied to a route setting anda navigation control of an underwater vehicle as well as amovement route and a movement control of a moving body

In step S48 , it is determined whether there is a need for
emergency surfacing. In a case where the obstacle sensor 28 according to a predetermined condition such as topography
detects an obstacle against the navigation of the underwater data and a reference attitude. For example, the invention isvehicle 100 , the control device 34 causes the process pro- 15 able to be applied to a movement route setting and aceed to step S50 to float the hull 10 urgently and ends the movement control of an airplane and a drone .
underwater navigation . On the other hand, in a case where
REFERENCE SIGNS LIST
no obstacle is detected, the process proceeds to step S52 .
With this process, the underwater vehicle 100 serves as an
emergency surfacing determination unit 82. Further, the 20 10 : hull
emergency surfacing may be performed by a command from12 : main propellera ship on the sea through the acoustic communication device
14 : main propeller drive motor
36 .

In step S52 , it is determined whether the hull reaches a

14a : battery

16 : vertical rudder
18 : vertical rudder drive motor

final underwater waypoint. The control device 34 deter- 25 20 : horizontal rudder
22 : horizontal rudder drive motor
waypoint of the underwater navigation route among thepredetermined underwater waypoints. If the hull reaches the
24 : depth indicator
26 : height indicator
final underwater waypoint, the process proceeds to step S54
to normally float the underwater vehicle 100 , and the under- 30 28 : obstacle sensor
30 : observation sensor
water navigation is ended . If the hull 10 does not reach the
32 : inertial navigation device
middle underwater waypoint, the process returns to step S44
34 : control device
to keep the navigation control toward the next underwater
36 : acoustic communication device
waypoint.
As described above , the underwater vehicle 100 can 35 38 : acoustic positioning device
navigate along an underwater navigation route and in an
40 : processing unit
42 : storage unit
underwater navigation attitude which are appropriate to a
purpose by performing the navigation control of the under44 : input unit
46 : output unit
water vehicle 100 to realize the underwater navigation route( the target values at the respective underwater waypoints) 40 50 : initial setting unit
set by the route setting method for the underwater vehicle .
52 : underwater waypoint setting unit
With this configuration , an observation of the underwater
54 : target value setting unit
56 : hull dynamic model setting unit
vehicle 100 can be realized in an optimum state . Further,
FIG . 5 illustrates a diagram for describing the route setting
58 : target value following simulation unit
process of the underwater vehicle according to the embodi- 45 60 : underwater navigation height confirming unit
62 : repetition count confirming unit
ment of the invention , which is an example when the routesetting method and the underwater vehicle 100 of this
64 : target value updating unit
embodiment are applied to a real sea area . Submarine
66 : optimum target value setting unit
resources were surveyed at Myojin knoll caldera located in
68 : optimum target value output unit
70 : optimum target value input unit
the sea near the Izu islands of Japan in June, 2015 using the 50 72: storage unit
unmanned underwater vehicle “URASHIMA” for naviga
74 : hull motion control unit
tion ( developed by Japan Agency for Marine- Earth Science
76 : subject vehicle motion detection unit
and Technology ) as the underwater vehicle 100. The“ URASHIMA ” navigated in the entire underwater naviga78 : subject vehicle position calculation unit
tion area at an average height of 67 m and a minimum height 55 80 : observation execution unitof 39 m ( a minimum setting height was 40 m) . The
82 : emergency surfacing determination unit
“ URASHIMA ” is a large underwater vehicle ( AUV ) having
100 : underwater vehicle
200 : route setting device
an overall length of 8 m . Assuming Myojin knoll caldera has
300 : support ship
an extremely rugged underwater bottom which has a steep
400 : submarine topographyslope of 53 degrees at maximum , the result shows that an 60 500: satellite
extremely high degree of difficulty has been cleared . Whenan appropriate route point is derived , an initial depth at each
The invention claimed is :route point is set at 120 m above from the underwater depth
1. A route setting method for an underwater vehicle ,of the corresponding coordinates ( latitude / longitude ), and an comprising:appropriate depth ( optimum target value ) at each route point 65 inputting an underwater waypoint of an underwater
is derived using the route setting method of the embodiment.
vehicle :In this way, according to the route setting method for thesetting an initial target value on the underwater waypoint;
mines whether the hull 10 reaches the final underwaterUS 11,048,274 B2
19

20

simulating an underwater navigation route of the under-

wherein , in the updating of the target value , the target

water 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 reference5
and the target value ;updating 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 ,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 ,wherein the target value is optimally derived by repeat- 10 wherein a value of the objective function is a total sum ofabsolute values of differences between the calculated
edly performing the simulation of the underwater navi
underwater navigation heights at a plurality of thegation and the updating of the target value ; andcontrolling, by a control device , navigation of the underunderwater waypoints and the minimum allowable
water vehicle at least based on the target value .
height, or a total sum of squares of the differences, and
2. The route setting method for an underwater vehicle 15 in the updating of the target value , the target height isaccording to claim 1 , wherein the target value is a target
updated such that the value of the objective function isdecreased .
depth on the underwater waypoint.
3. The route setting method for an underwater vehicle
10. The route setting method for an underwater vehicleaccording to claim 1 , further comprising:according to claim 2 , further comprising:setting a minimum allowable height of the underwater 20 setting a minimum allowable height of the underwater
vehicle ,vehicle ,updated such that the value of the objective function is

attitude is updated such that the value of the objective

wherein , in the simulation of the underwater navigation ,a calculated underwater navigation height of the underwater vehicle with respect to the target depth is simulated on the basis of the dynamic model of the under- 25
water 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

wherein , in the simulation of the underwater navigation,a calculated underwater navigation height of the underwater vehicle with respect to target reference attitude issimulated on the basis of the dynamic model of theunderwater 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 the30
depth .
optimum target reference attitude.
4. The route setting method for an underwater vehicle
11. The route setting method for an underwater vehicleaccording to claim 3 ,according to claim 10 ,wherein , in the updating of the target value , the target
wherein , in the updating of the target lue, the target
depth is updated such that a minimum value of thereference attitude is updated such that a minimum value
calculated underwater navigation height approaches the 35of the calculated underwater navigation heightminimum allowable height in a case where there is aapproaches the minimum allowable height in a casedifference between the minimum value of the calcu
where there is a difference between the minimum value
lated underwater navigation height and the minimumof the calculated underwater navigation height and theminimum allowable height.
allowable height.
5. The route setting method for an underwater vehicle 40 12. The route setting method for an underwater vehicleaccording to claim 3 ,according to claim 10 ,wherein a value of the objective function is a total sum of
wherein a value of the objective function is a total sum ofabsolute values of differences between the calculated
absolute values of differences between the calculated
underwater navigation heights at a plurality of theunderwater navigation heights at a plurality of theunderwater waypoints and the minimum allowable 45
underwater waypoints and the minimum allowableheight, or a total sum of squares of the differences, andheight, or a total sum of squares of the differences, andin the updating of the target value , the target depth isin the updating of the target value , the target reference
decreased.

function is decreased .

6. The route setting method for an underwater vehicle 50 13. The route setting method for an underwater vehicleaccording to claim 1 , wherein the target value is a target according to claim 1 ,height at the underwater waypoint.
wherein the number of repetitions of the simulation of the
7. The route setting method for an underwater vehicle
underwater navigation and the updating of the target
value is set in advance .
according to claim 6 , further comprising:setting a minimum allowable height of the underwater 55 14. The route setting method for an underwater vehicle

vehicle ,according to claim 1 , wherein a reference route is used
wherein , in the simulation of the underwater navigation , instead of the data of the submarine topography.
a calculated underwater navigation height of the under15. The route setting method for an underwater vehicle
water vehicle with respect to the target height is simu- according to claim 1 , wherein reference attitude angles oflated on the basis of the dynamic model of the under- 60 the underwater vehicle at the underwater waypoint is usedwater vehicle using the data of the submarine instead of the data of the submarine topography.
topography and the target height, and the calculated
16. The route setting method for an underwater vehicle
underwater navigation height and the minimum allow- according to claim 1 , further comprising:able height are compared to derive the optimum target
controlling the underwater vehicle using an optimum
65
height.
target value obtained by the simulation .
8. The route setting method for an underwater vehicle
17. The route setting method for an underwater vehicleaccording to claim 7 ,according to claim 16 ,

US 11,048,274 B2
21

wherein the optimum target value and a position of theunderwater vehicle are compared to control a motion

22

wherein the target value is optimally derived by repeat
edly performing the simulation of the underwaternavigation and the updating of the target value ;control system of the underwater vehicle according toa storage unit which stores the acquired optimum target
a comparison result.
5value ; and
18. An underwater vehicle comprising :amotioncontrol unit which controls a drive unit using thea target value acquisition unit which acquires an optimum
optimumtarget value stored in the storage unit.
target value , the optimum target value determined by :19. The underwater vehicle according to claim 18 , further
inputting an underwater waypoint of the underwater comprising:at least one of a depth measuring unit , a height measuring
vehicle ;10unit, and an attitude measurement unit,
setting an initial target value on the underwater way
wherein the motion control unit compares a measurement
point ;
value of at least one of the depth measuring unit, thesimulating an underwater navigation route of the underheight measuring unit, and the attitude measurement
water vehicle with respect to the target value on theunit with the optimum target value stored in the storagebasis of a dynamic model of the underwater vehicle 15unit to control the drive unit.
using data of a submarine topography as a reference
20. The underwater vehicle according to claim 18 , further
comprising :and the target value ; andan obstacle detection unit, wherein the motion control unit
updating the target value on the basis of an objective
controls the drive unit according to a detection result offunction which is calculated on the basis of the 20
the obstacle detection unit.
underwater navigation route obtained in the simu
lating of the underwater navigation,