Overview

LUST

IPSIT201227. 03. 2012. • Zagreb, Croatia

Autonomous robotic system in underwater mine countermeasures

Autonomous robotic system in underwater mine countermeasures

Laboratory for Underwater Systems and TechnologiesFaculty of Electrical Engineering and ComputingUNIVERSITY OF ZAGREB

Nikola Mišković

NATO Undersea Research Centre

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1. Introduction• System description

2. Mission• Scenario• Execution

3. Results• Simulation• Field test

4. Conclusion

Outline

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1. Introduction

State of the Art• Execution of preplanned missions• Selection of contact to be

investigated, reacquired, and neutralized is done by an operator through a post-mission analysis

Objective• Guide a simple unmanned

underwater vehicle (UUV) from a more capable, sonar equipped, platform, preferably an autonomous underwater or surface vessel (AxV)

Assumption• a survey has been done by an AUV

equipped with SAS sensor and the target has been identified

Motivation• Use collaborative autonomous

vehicles in MCM scenarios autonomous mine neutralization and disposal.

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1. Introduction

Possible solutions• Using LBL/USBL for navigation of UUV• PROS: more precise guidance• CONS: expensive

• Using a forward looking multibeam sonar for UUV guidance• PROS: cheap, UUV is dispensible• CONS: less accurate, UUV has to be in sonar’s field of view

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1. Introduction- System description

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UUV – automatic unmanned underwater vehicle• Equiped with acoustic receiver, compass, pressure sensor• Small, inexpensive, cheap and dispensible

1. Introduction- System description

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AxV – autonomous surface or underwater vehicle• Equiped with acoustic modem, GPS, compass, forward looking

multibeam sonar (BlueView P900)• Guides the UUV using sonar imagery

1. Introduction- System description

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AxV – autonomous surface or underwater vehicle• Equiped with acoustic modem, GPS, compass, forward looking

multibeam sonar (BlueView P900)• Guides the UUV using sonar imagery

1. Introduction- System description

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2. Mission- Scenario

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2. Mission- Scenario

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2. Mission- Scenario

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2. Mission- Scenario

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2. Mission- Scenario

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2. Mission- Scenario

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2. Mission- Scenario

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3. Mission- Execution

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3. Mission- Execution

• Tethered link or• Acoustic link

• transport delay!!• limited bandwith cca 40bit/sec• frequent dropouts

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2. Mission- Execution

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Advantages of the proposed system

• One way communication between the UUV and the AxV• KF enables UUV navigation when measurements are not

available• Only UUV has to be in the field of view (not the target)• If the AxV drifts due to currents, the UUV will not drift

with it but it will stay and the line which has

2. Mission

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- Coupled model of the UUV- Sonar measurement update

every 1 s. - control is performed at 10 Hz.- ASV forward speed u = 0.1m/s- ASV lateral speed due to

currents v = 0.015m/s. - The simulation results show

that the vehicle is behaving as expected even when the multibeam sonar carrier (the reference point) is mobile, as long as the UUV is in the field of view.

4. Results- Simulation

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• July 2010 @NURC• image processing and line-

following implemented

• September 2010 @BtS• the autonomy module

mounted• pool testing

• November 2010 @NURC • acoustic communication

and guidance implemented• Tests in field conditions

4. Results- Field tests

• April 2011 @NURC• Fully autonomous operation

• September 2010 @NURC• Sea tests

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4. Results- Field tests

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4. Results

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4. Results

movie

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4. Results

movie2

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5. Conclusion

What has been done:• Development of the automatic UUV• Sonar image processing• Initial testing with a tether• Preliminary trials with acoustic link

• Simulation results show that the vehicle is behaving as expected even when the multibeam sonar carrier (the reference point) is mobile, as long as the UUV is in the field of view.

• Field experiments have shown that lower resolution (and lower cost) sonar feedback can be used for guiding a simplified mine neutralization UUV to the moored or bottom mine

What we are doing:• Sonar image processing using motion

estimators• Extensive trials with acoustic link• Inclusion of transport delay in KF• System validation

Future plans:• Cooperative MCM scenario using two UUVs

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Thank you for your attention!