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Abstract
Rigid body modeling for estimation of aerodynamic derivatives from the flight responses of a flexible aircraft does not yield the true stability and control parameters of the aircraft, as the estimated derivatives absorb the aeroelastic effects present in the data. The analytical expressions for computing the rigid body derivatives from the flight-estimated values require knowledge of aircraft modal mass and generalized elastic deflections which is not always available. This paper considers a simplified approach based on quasi-steady representation of aeroelastic effects to identify the rigid body parameters from the flexible aircraft responses. Results show that, by combining data at several flight conditions, system identification method can be applied to separate the rigid body derivatives and the dynamic pressure dependent quasi-steady effects caused by structural deformation.
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References
- Waszak, M.R., Buttrill, C.S. and Schmidt, D.K., "Modeling and Model Simplification of AeroelasticVehicles: An Overview", NASA-TM-107691, September 1992.
- Waszak, M.R. and Schmidt, D.K., "Flight Dynamics of Aeroelastic Vehicle", Journal of Aircraft, Vol. 25, No. 6, 1988, pp. 563-571.
- Ghosh, A.K. and Raisinghani, S.C., "Parameter Estimates of an Aeroelastic Aircraft as Affected by Model Simplifications", Journal of Aircraft, Vol. 31, No. 2, March-April 1994, pp. 174-180.
- Schmidt, D.K. and Lee, S.K., "New Methods for Structured Uncertainty Modeling for Flexible Aircraft", AIAA-99-4157.
- Jategaonkar, R., Fischenberg, D. and Gruenhagen, W.V., "Aerodynamic Modeling and System Identification for Flight Data-Recent Application at DLR", Journal of Aircraft, Vol. 41, No. 4, July-August 2004, pp. 681-691.
- Hamel, P.G. and Jategaonkar, R.V., "The Role of System Identification for Flight Vehicle Applications-Revisited", RTO-MP-11, Paper 2, March 1999.
- Maine, R.E. and Iliff K.W., "Application of Parameter Estimation to Aircraft Stability and Control - the
- Output Error Approach", NASA RP 1168, 1986.
- Zerweckh, S.H. and Flotow, A.H, "Flight Testing a Highly Flexible Aircraft: Case Study on the MIT
- Light Eagle", Journal of Aircraft, Vol. 27, No. 4, April 1990, pp. 342-349.
References
Waszak, M.R., Buttrill, C.S. and Schmidt, D.K., "Modeling and Model Simplification of AeroelasticVehicles: An Overview", NASA-TM-107691, September 1992.
Waszak, M.R. and Schmidt, D.K., "Flight Dynamics of Aeroelastic Vehicle", Journal of Aircraft, Vol. 25, No. 6, 1988, pp. 563-571.
Ghosh, A.K. and Raisinghani, S.C., "Parameter Estimates of an Aeroelastic Aircraft as Affected by Model Simplifications", Journal of Aircraft, Vol. 31, No. 2, March-April 1994, pp. 174-180.
Schmidt, D.K. and Lee, S.K., "New Methods for Structured Uncertainty Modeling for Flexible Aircraft", AIAA-99-4157.
Jategaonkar, R., Fischenberg, D. and Gruenhagen, W.V., "Aerodynamic Modeling and System Identification for Flight Data-Recent Application at DLR", Journal of Aircraft, Vol. 41, No. 4, July-August 2004, pp. 681-691.
Hamel, P.G. and Jategaonkar, R.V., "The Role of System Identification for Flight Vehicle Applications-Revisited", RTO-MP-11, Paper 2, March 1999.
Maine, R.E. and Iliff K.W., "Application of Parameter Estimation to Aircraft Stability and Control - the
Output Error Approach", NASA RP 1168, 1986.
Zerweckh, S.H. and Flotow, A.H, "Flight Testing a Highly Flexible Aircraft: Case Study on the MIT
Light Eagle", Journal of Aircraft, Vol. 27, No. 4, April 1990, pp. 342-349.