Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-26T21:00:57.082Z Has data issue: false hasContentIssue false

A linear-quadratic-Gaussian approach for automatic flight control of fixed-wing unmanned air vehicles

Published online by Cambridge University Press:  27 January 2016

W.-L. Chan
Affiliation:
Institute of Aeronautics and Astronautics, National Cheng Kung University, Taiwan
S.-S. Jan
Affiliation:
Institute of Aeronautics and Astronautics, National Cheng Kung University, Taiwan
F.-B. Hsiao
Affiliation:
Institute of Aeronautics and Astronautics, National Cheng Kung University, Taiwan

Abstract

This paper presents the design and implementation of automatic flight controllers for a fixed-wing unmanned air vehicle (UAV) by using a linear-quadratic-Gaussian (LQG) control approach. The LQG design is able to retain the guaranteed closed-loop stability of the linear-quadratic regulator (LQR) while having incomplete state measurement. Instead of feeding back the actual states to form the control law, the estimated states provided by a separately designed optimal observer, i.e. the Kalman filter are used. The automatic flight controllers that include outer-loop controls are constructed based on two independent LQG regulators which govern the longitudinal and lateral dynamics of the UAV respectively. The resulting controllers are structurally simple and thus efficient enough to be easily realized with limited onboard computing resource. In this paper, the design of the LQG controllers is described while the navigation and guidance algorithm based on Global Positioning System (GPS) data is also outlined. In order to validate the performance of the automatic flight control system, a series of flight tests have been conducted. Significant results are presented and discussed in detail. Overall, the flight-test results show that it is highly feasible and effective to apply the computationally efficient LQG controllers on a fixed-wing UAV system with a relatively simple onboard system. On the other hand, a fully automatic 44km cross-sea flight demonstration was successfully conducted using the LQG-based flight controllers. Detailed description regarding the event and some significant flight data are given.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 2011 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Erdos, D. and Watkins, S.E. UAV Autopilot integration and testing, 2008, IEEE Region 5 Conference, pp 1-6.Google Scholar
2. Beard, R., Kingston, D., Quigley, M., Snyder, D., Christiansen, R., Johnson, W., McLain, T. and Goodrich, M.A. Autonomous vehicle technologies for small fixed-wing UAVs, J Aerospace Computing, Information, and Communication, January 2005, 2, pp 92108.Google Scholar
3. Hsiao, F.B., Hsieh, S.Y., Chan, W.L. and Lai, Y.C. Engine speed and velocity controller development for small unmanned aerial vehicle, J Aircr, 2008, 45, (2), pp 5565.Google Scholar
4. Montgomery, P.Y. Carrier Differential GPS as a Sensor for Automatic Control, 1996, PhD thesis, Stanford University.Google Scholar
5. Cho, A., Kim, J., Lee, S., Choi, S., Lee, B. and Kim, B. Fully automatic taxiing, takeoff and landing of a UAV only with a single-antenna GPS receiver, 2007, Proceedings of AIAA Infotech@Aerospace 2007 Conference and Exhibit, Rohnert Park, California, USA.Google Scholar
6. Tuzcu, I., Marzocca, P., Cestino, E., Romeo, G. and Frulla, G. Stability and control of a high-altitude, long-endurance UAV, J Guidance, Control and Dynamics, May-June 2007, 30, (3), pp 713721.Google Scholar
7. Lee, C.S., Hsiao, F.B. and Jan, S.S. Design and implementation of linear-quadratic-Gaussian stability augmentation autopilot for unmanned air vehicle, Aeronaut J, May 2009, 113, (1143), pp 275290.Google Scholar
8. Lee, C.S., Chan, W.L. and Hsiao, F.B. The Development of Spoonbill UAV and LPV modeling of longitudinal dynamics, 2008, Proceedings of 23rd Bristol International UAV Systems Conference, April 2008, Bristol, UK.Google Scholar
9. Lee, C.S., Chan, W.L. and Hsiao, F.B. Implementation of system identification on unmanned aerial vehicle via subspace and prediction error method, J Aeronautics, Astronautics and Aviation, 2010, Series A, 42, (2), pp 8798.Google Scholar
10. Lee, C.S. The Realization of Optimal Stability Augmentation Autopilot for Unmanned Air Vehicle, 2008, Master thesis, Institute of Aeronautics and Astronautics, National Cheng Kung University, Taiwan.Google Scholar
11. Nelson, R.C. Flight Stability and Automatic Control, 1998, Second edition, (Chapter 4-5), WCB/McGraw-Hill.Google Scholar
12. Ogata, K. Discrete-Time Control Systems, 1987, Prentice-Hall.Google Scholar
13. Stevens, B.L. and Lewis, F.L. Aircraft Control and Simulation, 2003, Second edition, John Wiley & Sons.Google Scholar