Virtual Environment for Ships and Ship-Mounted Cranes

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Virtual Environment for Ships and Ship-Mounted
Cranes

• Ali H. Nayfeh
• Lance Arsenault, Dean Mook, and Ron Kriz
• Virginia Polytechnic Institute
• and State University
• DURIP
• Supported by the Office of Naval Research
• Dr. Kam Ng, Technical Monitor

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MURI on Nonlinear Active Control of Dynamical
Systems

• Supported by the
• Office of Naval Research
• Dr. Kam Ng
• Technical Monitor

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Objectives of the MURI

• Develop a unified control methodology and control
  strategy for nonlinear dynamical systems and
  processes
• Develop controller architecture and control
  algorithms for both high- and low-level controls
  for undersea vehicles, shipboard crane operation,
  and large-scale power electronic systems
• Develop simulations of ship hydrodynamics and
  control methodologies that can be used to
  conceptualize advanced hull forms

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Concentration Areas
Unmanned Undersea Vehicles (UUV)
Power Electronics Building Blocks (PEBB)
Control Algorithms
Control Methodology Controller Architecture
Shipboard Crane Operation
Ship Motion Prediction Simulation Control
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Simulator Objectives

• State-of-the-art physical models are used to
  develop a state-of- the-art Ship and Crane
  Simulator Testbed at the Virginia Tech CAVE
• Testbed serves as a platform for testing ship and
  crane technologies
• Testbed can be used to test the boresight of
  sensors and data-link margins

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Virginia Tech CAVE

• Visual image generation system with three pipes
• Image generation computer
• Head motion tracking system
• Image display system
• Four high-resolution projectors
• Three projection walls and one projection floor
• Liquid crystal eyes stereoscopic system
• Sound simulation system
• Six-degree-of-freedom motion base

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CAVE Capability

• Computer-generated multi-sensory information is
  rear projected in stereo onto the walls and floor
  of the CAVE and viewed with stereo glasses
• Head motion tracking system allows the viewer to
  walk around the system
• The viewer could see what amounts to an action
  theatre of one or more ships
• The theatre extends beyond the walls of the CAVE
• The viewer experiences all design variables in
  concert
• Engineers can create and evaluate system
  prototypes

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Simulator Characteristics

• Moving platform
• Simulates the motion of a ship
• Permits a virtual movement about and inspection
  of the ship and experiencing its motion in high
  sea states
• Crane operator functions in a highly realistic
  virtual environment complete with
• High-fidelity 270 degree scene visualization
• Ambient sound
• Base motion
• Physical control console
• Chair and cupola

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Visualization of Ship Motion and Control

• Large-amplitude (nonlinear) ship motion
• Simulations of ship hydrodynamics
• Motion control systems
• Anti-roll tanks
• Anti-roll weights
• Hull-mounted fins
• Hull-mounted cavitating spoilers
• Hybrid designs with rudder action and course
  keeping
• Evaluation of different hull designs

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Destroyer Model in a Regular Head Sea-Only Pitch
Motion is Directly Excited
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Cargo Transfer at Sea
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3D Uncontrolled Response

• Animation is faster than real time.
• 2 Roll at wn.
• 1 Pitch at wn.
• 1 ft Heave at 2wn.

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3D Controlled Response

• Animation is faster than real time.
• 2 Roll at wn.
• 1 Pitch at wn.
• 1 ft Heave at 2wn.

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3D Controlled ResponseSlew Maneuver

• Animation is faster than real time.
• 2 Roll at wn.
• 1 Pitch at wn.
• 1 ft Heave at 2wn.

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Experimental Demonstration

• Built 3-DOF Ship Motion Simulation Platform
• General Pitch, Roll, and Heave capability
• Sinusoidal excitations in present results
• Equipped 1/24th scale model of T-ACS crane (NSWC)
  with motor and cable
• Crane control executed on PC

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Uncontrolled Response

• 1 Roll at wn.
• 0.5 Pitch at wn.
• 0.5 in Heave at 2wn.

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Controlled Response

• 1 Roll at wn.
• 0.5 Pitch at wn.
• 0.5 in Heave at 2wn.

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Controlled Response

• 2 Roll at wn.
• 1 Pitch at wn.
• 0.5 in Heave at 2wn.

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Controlled ResponseSlew Maneuver

• 1 Roll at wn.
• 0.5 Pitch at wn.
• 0.5 in Heave at 2wn.

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Controlled ResponseSlew Maneuver

• 2 Roll at wn.
• 1 Pitch at wn.
• 0.5 in Heave at 2wn.

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Motion Base
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System Software Design
complete
Motion Base controller
sensors
Crane Model crane dynamics
LAMP ship dynamics
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VT CAVE
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Desktop simulator of the VR Crane Ship Simulator
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Progress

• CAVE running in new building

• With motion base
• Or flat floor
• Crane motion

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Platform for Testing Technologies

• Response of (individual and multiple) ships in a
  dynamic sea environment
• Integrated ship-motion prediction and control
• Determination of how different hull forms operate
  in various sea states
• Control of cargo handling aboard ships in high
  sea states
• Animation and visualization of ship and crane
  systems in a dynamic sea environment
• Virtual prototyping of ships and cranes,
  including the input of operators
• Ship- and crane-operator training
• Collaborative environment

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http//thor.sv.vt.edu/crane/