H∞ Control of the NRC Bell 205 Fly-by-Wire Helicopter

Postlethwaite, Ian; Smerlas, Alex; Walker, Daniel J.; Gubbels, Arthur; Baillie, Stewart; Strange, M. E.; Howitt, J.

doi:10.4050/jahs.44.276

Cited by 32 publications

(15 citation statements)

References 5 publications

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“…Over the past several years, it has been established that successful nonlinear simulation, conforming to the above rules, leads to successful flight tests. This contrasts sharply to earlier work where stabilty was not certain from test to test (Postlethwaite et al, 1999;Walker et al, 1999).…”

Section: Nonlinear Simulationscontrasting

confidence: 55%

“…It builds upon work reported in Postlethwaite et al (2002) and Postlethwaite et al (2005) where results on H ∞ control of the Bell 205 from flight tests in 2001 were reported. In turn that work progressed the work reported in Postlethwaite et al (1999) and Walker et al (1999) and references therein. Postlethwaite et al (2002) and Postlethwaite et al (2005) described several controllers which yielded Level 1 behaviour, in terms of their achieved bandwidths and, essentially, borderline Level 1/2 behaviour handling qualities ratings from testpilots.…”

mentioning

confidence: 59%

“…The model (Howell and communication, 2001), provided by QinetiQ (formerly DERA) was a 32-state nonlinear flight mechanic model of the Bell 205. This was an improved version of the model (Strange and Howitt, 1998) used for the flight tests described in (Postlethwaite et al, 1999) and and simulation results from the former model proved to be close to those obtained in-flight.…”

Section: Modelmentioning

confidence: 99%

See 2 more Smart Citations

Robust Control Applications

Postlethwaite

Turner

Herrmann

2006

IFAC Proceedings Volumes

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This paper (first presented as a plenary lecture at the 5th IFAC Symposium on Robust Control Design, Toulouse, July 2006) demonstrates the practical importance of robust control theory by describing its application to two non-trivial practical control problems. Part 1 considers helicopter control and Part 2 addresses saturation problems in high-performance head-positioning servo systems in high-density hard-disk drives.In Part 1, we present the design and flight test of a new batch of H ∞ controllers for the Bell 205 helicopter. At the heart of each controller is an H ∞ loop-shaping controller, augmented with a hand-tuned reference filter to improve tracking performance and to reduce a perceived phase lag which pilots had complained of previously. Flight testing revealed that, with such an architecture, it was relatively easy to get Level 1 handling qualities ratings in low aggression manoeuvres. Further fine tuning resulted in Level 1 qualities for high aggression manoeuvres and one controller performed to Level 1 standard in all manoeuvres tested.In Part 2, we consider how robust control techniques can be used to design anti-windup compensators to counter performance and stability problems associated with saturating actuators in state-of-the-art hard-disk drive servo systems. A promising two-stage approach is given and illustrated with experimental results.

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Section: Nonlinear Simulationscontrasting

confidence: 55%

mentioning

confidence: 59%

Section: Modelmentioning

confidence: 99%

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Robust Control Applications

Postlethwaite

Turner

Herrmann

2006

IFAC Proceedings Volumes

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“…[30]. The first helicopter flight-test of an H ∞ controller was conducted in 1997 by the Control Group of the University of Leicester, UK, [26], [25], [22] with subsequent flight tests reported in [29]. More recently, the application of loop-shaping procedures to a new non-linear model of the Bell 205 has led to several improvements [27], [21].…”

Section: Introductionmentioning

confidence: 99%

Static H/sub /spl infin// loop shaping control of a fly-by-wire helicopter

Prempain

Postlethwaite²

2004

2004 43rd IEEE Conference on Decision and Control (CDC) (IEEE Cat. No.04CH37601)

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This paper introduces a novel static output feedback version of the design procedure of McFarlane and Glover [18]. Existence conditions for a static output loop shaping controller are given in terms of two coupled matrix inequalities. Simple linear sufficient conditions can be derived from these coupled nonlinear inequalities and the determination of a static, sub-optimal, H ∞ loop shaping controller reduces to an optimization problem over Linear Matrix Inequalities. The new procedure is demonstrated by its application to the design of a flight control system for the Canadian fly-by-wire research Bell 205 helicopter. The resulting H ∞ controller has just 3 states and would appear to be the simplest flight control system used on this helicopter. The system was successfully flight-tested and high levels of performance were achieved.

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“…6 Decoupling of helicopter dynamics tempts (6) - (8) to apply modern control theories to the helicopter control problem because the modern control approach offers many superior features over classical controls such as: decoupling, robustness, and sophisticated performance specification, although it has not won many practitioners in the industries yet. Our goal in this research is to design a proper controller for a working autopilot system for a model helicopter.…”

Section: Controller Designmentioning

confidence: 99%

System Identification and 6-DOF Hovering Controller Design of Unmanned Model Helicopter

Kim

Chang

Lee

2006

JSME Int. J., Ser. C

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For a maneuvering unmanned autonomous helicopter, it is necessary to design a proper controller for each flight mode. In this paper, the overall helicopter dynamics is derived and a hovering model is linearized and transformed into a state-space form. However, since it is difficult to obtain parameters for stability derivatives in the state-space directly, a linear control model is derived by a time-domain parametric system identification method with real flight data of a model helicopter. Then, two different controllers (a linear feedback controller with the proportional gain and a robust controller) are designed and their performances are compared. The simulation results show outstanding performance. The validated controllers can be utilized to enable autonomous flight of a RUAV (Rotorcraft-based Unmanned Aerial Vehicle).

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H∞ Control of the NRC Bell 205 Fly-by-Wire Helicopter

Cited by 32 publications

References 5 publications

Robust Control Applications

Robust Control Applications

Static H/sub /spl infin// loop shaping control of a fly-by-wire helicopter

System Identification and 6-DOF Hovering Controller Design of Unmanned Model Helicopter

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