[UCI-CalIT2] Seminar February 20: GPS-based control of an autonomous marine c raft

[Stuart A ROSS]

"System Identification for Precision Control of a GPS-autonomous WingSailed
Catamaran"

Dr. Gabriel H. Elkaim

McDonnell-Douglas Auditorium
Thursday, February 20, 2003
11:00 am - 12:00 noon


ABSTRACT:   
Is it a boat, a plane, something in between? This presentation details the
Atlantis project, whose aim is the design, development, and experimental
testing of an autonomous wind-propelled marine craft.  Functionally, such a
vehicle is the marine equivalent of an unmanned aerial vehicle (UAV), and
would serve similar purposes.  The Atlantis project has been able to
demonstrate an advance in control precision of a wind-propelled marine
vehicle from typical commercial autopilot accuracy of 100 meters to an
accuracy of better than one meter with a prototype based on a modified
Prindle- 19 light catamaran.  The project involves substantial innovations
in three areas: wind propulsion system, overall system architecture, and
sensors.  The wind-propulsion system is a rigid wing-sail mounted vertically
on bearings, mass balanced to allow free rotation in azimuth about a
stub-mast.  Aerodynamic torque about the stub-mast is trimmed using a flying
tail mounted on booms aft of the wing.  This arrangement allows the
wing-sail to automatically attain the optimum angle to the wind, and
weathervane into gusts without inducing large heeling moments.  The sensor
system uses differential GPS (DGPS) augmented by a low-cost attitude system
based on accelerometer- and magnetometer-triads for position and velocity
measurements.  Accurate attitude determination is required to create a
synthetic position sensor that is located at the center-of gravity (c.g.) of
the boat, rather than at the GPS antenna location.  A high-performance
estimator/controller was implemented and tested on the full-scale prototype.
The identified controllers were able to perform remarkably well, in the
presence of wind and waves, tracking the line to within 0.3 meters (~1
foot). 


SPEAKER:
Gabriel Elkaim attended Princeton University for his bachelor's degree in
Mechanical and Aerospace Engineering (1990).  Following that he worked for a
French oil field services company, Schlumberger, aiding in oil exploration
on coastal West Africa and in the Sahara.  He started at Stanford in 1993 in
the Aeronautics and Astronautics department, where he finished his master's
degree and then his Ph.D. this past April.  Dr. Elkaim's hobbies include
hang gliding, photography, scuba diving, and flying light airplanes. 

Dr. Elkaim is a candidate for the Cal-(IT)2 Intelligent Transportation
Systems Faculty Position.


Faculty host:  Dr. Will Recker, Civil and Environmental Engineering