Experimental Validation of GPS-Based Control of an Unmanned Wing-Sailed Catamaran

Gabriel Hugh Elkaim and C.O. Lee Boyce

Abstract:	Precision guidance and control of an autonomous, wingsailed catamaran has been demonstrated by Harbor Wing Technologies’ X-1. Based closely on the Atlantis project, the X-1 is larger, more capable version. The platform is a modified Stiletto, a 9.1 m (30 ft) catamaran, experimentally capable of navigating along straight line segments between GPS waypoints and achieving line tracking with average errors/standard deviations of 1.6 m/1.4 m error in protected water and 3.3 m/1.8 m error in open water, respectively. The X-1 uses a novel hybrid propulsion system consisting of electric motors, powered from an on-board battery bank, and the wing-sail. If the minimum speed required for the current line segment is not achieved under wind power, the electric motors provide the remaining thrust. Power consumed under electric motor power can be in excess of 7 kW (10 HP) for 3 m/s (6 knots) of boat speed. Under hybrid propulsion, power has been shown to be 240 W for similar speeds. X-1’s control system configures the wing for maximum performance based on the estimated polar angle, the angle between the true wind and the vessel’s heading. Currently, travel upwind with a polar angle less than 30 is performed solely under electric motor. Using the line tracking capabilities of the platform, a new test pattern has been developed to derive performance data for the vehicle. Preliminary boat polar data shows X-1 capable of achieving 50% of true wind speed for 10 of tail angle and no flap deflection.
Published in:	Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007) September 25 - 28, 2007 Fort Worth Convention Center Fort Worth, TX
Pages:	1950 - 1956
Cite this article:	Elkaim, Gabriel Hugh, Boyce, C.O. Lee, "Experimental Validation of GPS-Based Control of an Unmanned Wing-Sailed Catamaran," Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007), Fort Worth, TX, September 2007, pp. 1950-1956.
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