Marine Cybernetics Laboratory

The Marine Cybernetics Laboratory is a quite small wave basin, located in what was originally a storage tank for ship models made of paraffin wax.

As the name indicates, the facility is especially suited for tests of marine control systems, due to the relatively small size and advanced instrumentation package. It is also suitable for more specialized hydrodynamic tests, mainly due to the advanced towing carriage, which has capability for precise movement of models in 6 degrees of freedom.

The MCLab is operated by the Department of Marine Technology, and has been a Marie Curie EU Training Site since 2002. It is mainly used by Master and PhD-students, but it is also available for MARINTEK and external users.

The software in use was developed using rapid prototyping techniques and automatic code generation under Matlab/Simulink and Opal. The target PC onboard the vessel runs the QNX real-time operating system while experimental results are presented in real-time on a host PC using Labview.

Capacities
 

  • Tank Dimensions: L x B x D = 40m x 6.45m x 1.5m
  • Wave maker
  • Carriage : towing speed 2 m/s, 5 (6) DOFs forced motions
  • Computer system for control, data recording and analysis
  • Typical scaling ratios: l = 50-150
  • Typical ship model lengths:1-3m
  • Positioning System measure 6DOF in Real-Time

Experimental Set-ups
 

  • DP and way-point tracking (wireless control) of ships and semi-submersibles
  • Crane operations
  • Propulsor and thruster control
  • Rapid control prototyping
  • Planar motion mechanism (PMM) and vertical motion mechanism (VMM) tests
  • Calibration of transducers
  • Hardware-In-the-Loop (HIL) Experiment Laboratory.

Real-Time Positioning System

Qualisys supplies a range of hardware and software products for motion capture and analysis of movement data. The key components of the system are the Oqus cameras and the Qualisys Track Manager (QTM) software. For advanced analysis of the movement data Qualisys supplies third party software products such as Visual3D from C-Motion, Inc.

Measurement data can be exported in different standard formats for use in customer-developed and other third party software. The Qualisys products are designed to meet the highest demands for quality, simplicity, speed and precision. Systems, built from the Qualisys products, are flexible, mobile and expandable and are therefore easy to adapt to varying needs in industry, research and clinical use.

Tracking a model vessel’s motions under different wave, current or wind conditions is one of the fundamental tasks at a hydrodynamics lab or a naval test site. Traditionally, this has been accomplished with potentiometer systems attached to a model or with bulky and expensive gyroscopes and accelerometers. Qualisys AB offers a easy, quick and functional way to obtain accurate 3D and 6 DOFs. With optical capture technology, your models remain completely unburdened by heavy sensors. Thanks to the low-mass optical targets, even very small and light models can be used.

Towing tank - In a towing tank, as few as 2 or 4 cameras can suffice, depending on the configuration. The cameras can be put on the towing carriage, which puts the model and the markers in the line of sight.

Oqus specifications

Camera output modes

Marker coordinates, high speed video*, streaming video*

Built-in camera display

128 x 64 graphical high contrast OLED

Camera body

Custom, die-cast aluminum

Camera size Oqus 100

185 × 110 × 124 mm (7.3 × 4.3 × 4.9 inches)

Camera size Oqus 300/500

200 × 145 × 155 mm (7.9 × 5.7 × 6.1 inches)

Weight including optics

1.9 kg Oqus 100 – 2.1 kg Oqus 300/500 (4.2 – 4.6 lbs)

Cooling

Convection cooling

Camera protection level*

Water resistant IP67 housing available

Operating temperature

0-35 °C

Firmware

Upgradeable from host computer

Position data noise level

+/- 1 camera units

Adjustable threshold

Yes

Frame buffer speed

12.9 Gbyte/second

Maximum frame buffer size

1152 Mbyte

Cabling

Hybrid cable with Ethernet and power

Wired communication

Hubless daisy-chained Ethernet 802.3@100Mbps

Wireless communication*

WLAN 802.11b/g@54Mbps

Power supply

Daisy-chained power from mains adaptor

Power

36-72 VDC, 10-16 VDC (battery) at 30 W maximum

Battery*

Available Q4-2008

Lens types*

Standard 40 degrees HFOV (many other options available)

Strobe types supported*

Infrared, red and blue/green

   
 

3-SERIES

CMOS sensor size (pixels)

1280×1024

Maximum frame rate at full resolution and field-of-view

500 fps

Maximum frame rate at full resolution and reduced field-of-view

10000 fps

x-coordinate full scale range (camera units)

82000

y-coordinate full scale range (camera units)

65000

Maximum video frame rate (full resolution)

500 fps

Maximum video buffer capacity (full resolution)

900 frames

Maximum video buffer capacity (full resolution and frame rate)

1.8 s

* Optional accessory/feature - Qualisys reserves the right to change specifications without notice

Three of these cameras together with a PC are installed in McLab pr. 2010.

Wave Maker with AWACS

- Delivered by DHI.

The wave maker is a 6 meter width single paddle and is operated with a electrical servo actuator. The system is equipped with a Active Wave Absorption Control System (AWACS 2). The system has a DHI Wave Synthesizer which can produce regular and irregular waves.

Capacity of the wave maker:

  • Regular waves H < 0.25, T = 0.3 – 3 s.
  • Irregular waves Hs < 0.15 m, T = 0.6 – 1.5 s.
  • Available Spectrums: JONSWAP, Pierson-Moskowitz, Bretschneider, ISSC, ITTC, …
  • Wave controller update rate = 10 Hz
  • No. wave gauge on paddle = 4
  • Stroke length on actuator = 590 mm.
  • Speed limit = 1.2 m/s.

Towing Carriage

The carriage can be operated in manual or computer controlled mode. The manual operation is done from the consol on the carriage. There is made a special Labview and Opal application to setup regular or irregular movement of the different axes.

Axes

The axis limits given in the table refers to the absolute coordinates in the remote control system. The ranges are the safe and practical limits, as of May 2005. These may be subject to change. Normal Speed is the speed used when returning to reference position.

Axis

Min
[m]

Max  [m]

Pos Error
[mm]

Normal Speed
[m/s]

Max Speed
[m/s]

Max Acc
[m/s^2]

X

Main Carriage (Gantry)

-15.5

8.5

±20

0.5

2.0

0.5

Y

Transverse carriage

-2.4

2.4

±5

0.2

1.0

1

U

small Carriage in X direction

-0.4?

0.4?

±1

0.2

1.0

1

C

Rotation Table

 

 

±.1°

 

 

 

Z

Vertical Axis

-0.2?

0.2?

±0.5

0.1

0.5

2

W

Vertical Axis

-0.2?

0.2?

±0.5

0.1

0.5

2

Positive direction is based on a maneuvering type coordinates with Z and W positive downwards.

Wavemaker - diagramWavemaker - photo

Mechanism wall, with waves clearly visible in pool
Wave maker

Hall with towing sledge at far end
Marine cybernetics basin

Model ship cresting wave
Scaled models can be run without cables thanks to a wireless ethernet connection and a micro-PC onboard.