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

MURI on Nonlinear Active Control of Dynamical Systems Supported by the Office of Naval Research Dr. Kam Ng Technical Monitor

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

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

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

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

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

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

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

Destroyer Model in a Regular Head Sea- Only Pitch Motion is Directly Excited

Cargo Transfer at Sea

3D Uncontrolled Response Animation is faster than real time. 2° Roll at  n. 1° Pitch at  n. 1 ft Heave at 2  n.

3D Controlled Response Animation is faster than real time. 2° Roll at  n. 1° Pitch at  n. 1 ft Heave at 2  n.

3D Controlled Response Slew Maneuver Animation is faster than real time. 2° Roll at  n. 1° Pitch at  n. 1 ft Heave at 2  n.

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

Uncontrolled Response 1° Roll at  n. 0.5° Pitch at  n. 0.5 in Heave at 2  n.

Controlled Response 1° Roll at  n. 0.5° Pitch at  n. 0.5 in Heave at 2  n.

Controlled Response 2° Roll at  n. 1° Pitch at  n. 0.5 in Heave at 2  n.

Controlled Response Slew Maneuver 1° Roll at  n. 0.5° Pitch at  n. 0.5 in Heave at 2  n.

Controlled Response Slew Maneuver 2° Roll at  n. 1° Pitch at  n. 0.5 in Heave at 2  n.

Motion Base

System Software Design DTK Server memory manager SharedMemory system state Motion Base com motion base Motion Base controller command base state LAMP ship dynamics ship Fun Filter motion filter motion graphics Render draw visual Crane Model crane dynamics crane Crane Control operator filter Operator Input joysticks/buttons joysticks buttons sensors MotionTracker non-magnetic head wand *complete

Sound simulator driven SharedMemory system state command base state ship motion graphics crane joysticks buttons head wand

VT CAVE

Desktop simulator of the VR Crane Ship Simulator GUIs emulate real devices Powered by DIVERSE

Progress CAVE running in new building With motion base Or flat floor Crane motion

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