This study presented results from the pilot-in-the-loop simulated flight tests of an LoC prediction and prevention system for NASA’s Transport Class Model. The purpose of these tests is to determine whether or not the LoC prediction and prevention system is capable of detecting and arrest- ing the development a sequence of events that may lead to an aircraft loss of control or initiating a recovery procedure to bring the aircraft back to a safe flight condition. The proposed LoC prediction and prevention system has been integrated to the simulation environment at the Illinois Simulator Laboratory at the University of Illinois at Urbana-Champaign. A test plan has been developed and several tests have been conducted for the preliminary assessment of the LoC prediction and prevention system. The test results have shown that the LoC prediction and prevention system does not affect the execution of standard maneuvers in normal flight operation and it is able prevent the aircraft loss of control based on the quantitative definition intro- duced by Wilborn and Foster. However, in the scenario where the aircraft experienced adverse environmental conditions at lower altitude, the system appears to be over-restricting the pilot from performing required maneuvers for the recovery.
Future work will include modifications to LoC prediction algorithm such that altitude is taken into consideration to prevent the system from constrain- ing the pilot from performing required maneuvers to avoid ground contact. Besides the altitude, the simulation results from the microburst scenario have also shown the need to take the rate of change of the angle of attack into account as the rapid changes of the wind direction may affect the value of angle of attack read by the sensor. Moreover, the FEP-limit adjustment logic will have to be modified such that it takes flight envelope priorities into account instead of the current implementation, which uses the chronological
more test scenarios will be conducted for the handling qualities assessment and validation of the LoC prediction and prevention control system. A more rigorous approach will be taken to evaluate the performance of the overall control system to ensure that it meets the pilots’ acceptance of the han- dling qualities, and to investigate potential adverse interactions between the LoC prevention system and the test pilots. Finally, the baseline flight con- trol law developed under the iReCoVeR framework will be augmented with an L1 adaptive controller, which guarantees robustness of the closed-loop
system with fast adaption in the presence of uncertainties and disturbances. An in-depth description of the L1 adaptive-control theory is available in [21]
REFERENCES
[1] P. Russell and J. Pardee, “JSAT Loss of Control Final Report: Results and Analysis,” Federal Aviation Administration, Commercial Aviation Safety Team, Washington D.C., Tech. Rep., December 2000.
[2] “Statistical summary of commercial jet airplane acci- dents, worldwide operations, 1959-2012,” Boeing Com- mercial Airplanes, August 2013. [Online]. Available: http://www.boeing.com/news/techissues/pdf/statsum.pdf
[3] C. M. Belcastro and J. V. Foster, “Aircraft loss-of-control accident anal- ysis,” in AIAA Guidance, Navigation and Control Conference, Toronto, Canada, August 2010, AIAA 2010–8004.
[4] C. M. Belcastro and S. R. Jacobson, “Future integrated systems concept for preventing aircraft loss-of-control accidents,” in AIAA Guidance, Navigation and Control Conference, Toronto, Ontario, Canada, August 2010, AIAA 2010–8142.
[5] N. Hovakimyan, “iReCoVeR Executive Summary,” 2012, –available on demand.
[6] J. E. Wilborn and J. V. Foster, “Defining commercial transport loss- of-control: A quantitative approach,” in AIAA Atmospheric Flight Mechanics Conference and Exhibit, Providence, RI, August 2004, AIAA 2004–4811.
[7] R. M. Hueschen, “Development of the Transport Class Model (TCM) aircraft simulation from a sub-scale Generic Transport Model (GTM) simulation,” NASA, Technical Memorandum 217169, August 2011. [8] K. A. Ackerman, S. T. Pelech, R. S. Carbonari, N. Hovakimyan, and
A. Kirlik, “Pilot-in-the-loop flight simulator for NASA’s Transport Class Model,” in AIAA Guidance, Navigation and Control Conference, Na- tional Harbor, MD, January 2014.
[9] J. Chongvisal, N. Tekles, E. Xargay, D. A. Talleur, A. Kirlik, and N. Ho- vakimyan, “Loss-of-control prediction and prevention for NASA’s Trans- port Class Model,” in AIAA Guidance, Navigation and Control Confer- ence, National Harbor, MD, January 2014.
[10] B. L. Stevens and F. L. Lewis, Aircraft Control and Simulation. Hobo- ken, NJ: John Wiley & Sons, 1992.
[11] M. V. Cook, Flight Dynamics Principles. Oxford, UK: Butterworth- Heinemann Ltd, 1997.
[12] B. L. Stevens and F. L. Lewis, Dynamics of Atmospheric Flight. New York, NY: John Wiley & Sons, 1972.
[13] The Boeing Company, “Angle of attack,” AERO Magazine, vol. 12, Oct. 2000.
[14] J. D. Anderson, Jr., Introduction to Flight. New York, NY: McGraw- Hill, 2008.
[15] G. Avanzini, “Dynamics of Flexible Aircraft,” November 2012, Lecture Note.
[16] “Airplane upset recovery training aid,” Federal Aviation Administra- tion, Tech. Rep., October 2008.
[17] N. Tekles, E. Xargay, R. Choe, N. Hovakimyan, I. M. Gregory, and F. Hozapfel, “Flight envelope protection for NASA’s Transport Class Model,” in AIAA Guidance, Navigation and Control Conference, Na- tional Harbor, MD, January 2014.
[18] “Illinois simulator laboratory,” Beckman Institute Illinois Simula- tor Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, http://www.isl.uiuc.edu/index.htm [Online; accessed 27 November 2013].
[19] National Transportation Safety Board, “Aircraft Accident Report,” Tech. Rep. NTSB/AAR-86/05.
[20] J. A. A. Fernando Caracena, Robert Ortiz, “The Crash of Delta Flight 191 at Dallas-Fort Worth International Airport on 2 August 1985 : Mul- tiscale Analysis of Weather Conditions,” Tech. Rep. ERL 430-ESG 2. [21] N. Hovakimyan and C. Cao, L1 Adaptive Control Theory. Philadelphia,
PA: Society for Industrial and Applied Mathematics, 2010.
[22] N. Hovakimyan, C. Cao, E. Kharisov, E. Xargay, and I. M. Gregory, “L1 adaptive control for safety-critical systems,” IEEE Control Systems