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This article proposes a fuzzy state noise-driven Kalman filter for sensor fusion to estimate the instantaneous position and attitude of an unmanned air vehicle for navigation purpose. The formulation of the state noise covariance matrix has been carried out using the fuzzy regression method applied to the state residuals. This algorithm has been embedded in the real-time hardware and tested for performance on ground and not in real flight. A comparative study between the proposed and conventional algorithm illustrates its efficacy. 16 Julier, S., Uhlmann, J., and Durrant-Whyte, H. F. A new method for the nonlinear transformation of means and covariances in filters and estimators.

This paper describes the development and flight testing of a personal air vehicle by team Harmony for the Boeing GoFly X-prize challenge. For the $1mil grand prize, aircraft were scored by compact size, speed, low noise, and endurance. The team chose a coaxial electric helicopter configuration to maximize rotor area and reduce disk loading for efficiency and acoustic benefits. The rotors were designed through an extensive parametric study using an in-house performance code. Air loads were modeled in HPCMP CREATE™-AV Helios for validation, then used in an inhouse acoustics solver to estimate sound pressure levels. A quiet electric power train was developed, as well as a custom 11kWh, 200lb (90.7kg) battery pack. The flight dynamics of the configuration were modeled and the stability analyzed. Structural analysis was utilized in designing key load-bearing parts. Flight control was implemented with dual, independent, electronically coupled swashplates. First, a 1/3rd scale prototype aircraft was developed to validate the design and acoustic predictions. Then a full-scale, 520lb (235.4kg) prototype with an 8.5ft (2.59m) rotor diameter was developed and accumulated 19.5hrs of testing time. During hovering, the sound pressure levels at 50ft (15.24m) were 73dBA, remarkably low for a rotorcraft. The results of this study underscored the endurance limitation of electric flight due to poor battery performance, as well as the need for reliable, lightweight hardware for such applications.

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