Development and Initial Testing of an Autonomous Surface Vehicle for Shallow Water Mapping

Presenter : Mohamad Hilmi Mat Idris

M.H. Mat Idris *, M.I. Sahalan,M.A. Abdullah, Z.Z. AbidinAutonomous Agent Research Group (AARG), Department of Mechatronics Engineering.

Kulliyyah of Engineering, International Islamic University of Malaysia, 53100 Selangor Malaysia

Presentation Outline

• Introduction• System Design• Mechanical consideration• On-board computer and communication• Power supply• Navigation• Sensors Integration• Data Logging• Payload

• Result• Conclusion and Future Work

Introduction• Shallow water mapping - process to measure and map

the shape of the coastal, lake, dam or waterway.• Importance of ‘shallow water mapping’• Marine and freshwater resources and ecosystems are now recognized

as ranking among the world’s most valuable assets.• We need bathymetry/depth information to

• Manage environmental hazards (from coastal erosion to tsunami).• Sedimentation monitoring, volume calculation (river, dam).• Underwater construction (dams, bridges, marinas, coastal

protection)

• Conventional method• 1) Hydrography ship 2) Satellite 3) LiDaR

• Drawback of current method aka ‘gap’• Non capable for shallow and high turbidity and tight area.

• Proposed solution• Small portable Autonomous Surface Vessel ( which later called ‘ASV’).

System development

• ASV Initial SpecificationItem Specification

Hull Configuration Catamaran

Dimension 1170mm x 360mm x 150mm

Turning diameter 2mMax Payload 10kgAverage speed 4.5ktOperation time 3hours

• Mechanical consideration• Hull Type Selection (Catamaran vs Monohull)• Better Roll and pitch stability.

Catamaran (top) vs Monohull (bottom) stability comparison

System development

• Mechanical consideration• Hull Type Selection (Catamaran vs. Mono-hull)• Easy access to water ( for underwater

sensors)• Less drag force compare to mono-hull (more

energy saving)• Hull Material type(fiber glass)• Robust for field deployment

System development

• On-board computer and communicationBase station (autonomous)• Laptop (Matlab GUI)• BlackBox RF Modem

Base station (manual)• Futaba RC Transmitter

On-board Electronics• Blackbox RF modem• Futaba RC Receiver• Arduino Mega

Payload Sensor• GPS, Sonar, Compass,

Probes (Serial RS232-NMEA 1803)

System development

• Power supply• Two types of batteries (estimate 3 hours operation*)• 12V/4000mAH LiPo batteries connected in series,

providing 24V nominal voltage for propeller• 12V 9800mAH battery pack. Additional DC/DC

converter is used to provide power sharing between the devices.

12V Litium-Ion Capacity : 9800mAH

12V Litium Polimer Capacity : 4000mAH

System development

• Navigation• Garmin eTrex® H, a high-sensitivity

GPS receiver that can to lock onto satellite signals quickly and maintain accuracy up to ±3m during clear view sky.

• KVH C100 Fluxgate Industrial-grade compass module that has accuracy up to 0.1°, ±0.5° resolution, ±45° tilt angle compensation and 1 second response time

• Both sensors are RS-232 and NMEA 0183 compatible for easy integration.

Waypoint navigation flowchart

System development

• Payload and Sensors Integrations• AtlasScientific water probes (e.g. pH, conductivity, dissolve

oxygen, and oxidation reduction potential)

Water Probes

Sonar Sensor

GPS

NMEA 1803

NMEA 1803

NMEA

1803

NMEA DATACOMBINER Micro Controller

Data Parsing and data logging

SD card module

RF Transceiver

System development

• Maneuvering Test• Straight line test• Using RC operation• Max speed : 8m/s• Bad reverse thrust

• Circle Maneuver• Minimum turning diameter : 4meter• Fairly enough for survey operation (lawn mower)• 360 rotation if more preferable for very tight area.

Result of Experimentation Test

• Sensors Reading and Logging

$GPGSV,3,3,11,30,30,175,35,07,05,153,00,09,13,119,00*4B $PENV,7.00,8.19,272.28,12.36,6,0.00,1.000*51 $SDMTW,023.1,C*34

//Channel 0 @ pH 7.00 //Channel 1 @ Dissolve Oxygen 8.19 //Channel 2 @ Oxidation Reduction Potential 272.28 //Channel 3 @ Conductivity 12.36,6,0.00,1.00

Raw Data

Excel Format Data

Result of Experimentation Test

• Field Test (Plot of data)• Swimming Pool Test, IIUM Sport Complex• Small Pond, NAHRIM• Maryam Lake, IIUM

Person Monitoring Data at Base Station

Field test devices setup

Result of Experimentation Test

Depth Swimming Pool, IIUM Sport Complex

Depth plot Small Pond, NAHRIM

Result of Experimentation Test

Depth plot at Maryam Lake, IIUM

Result of Experimentation Test

• Conclusion• Small portable ASV had proven to fill the gap between LIDAR,

satellite bathymetry and hydrographic vessel.• The catamaran hull provide platform stability to enhance

performance of data measurement.• The mission test and real scenario trial proved the operability of

the ASV for a shallow water mapping operation.• In its current form, the boat meets its design objectives by its

capability of safely maneuver at a very shallow and tight area while collecting bathymetry data.

• Future work• Development of additional payload modules.• upgrade of navigation sensors• incorporation of robust navigational controller to enhance

performance in strong current and wind• the used of vision-based navigation system in negotiation above

and below water obstacles

Conclusion and Future Work