Effects of Pitch Instantaneous Center of Rotation Location on Flying Qualities

Field, Edmund; Armor, James; Rossitto, Kenneth F.; Mitchell, David G. M.

doi:10.2514/6.2002-4799

Cited by 9 publications

(5 citation statements)

References 1 publication

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“…and heave motion with respect to the c.g. could alternatively have been performed using the instantaneous center of pitch rotation as described in [11]. However, due to the modest size of the aircraft considered in this study, a Cessna Citation I, the difference between both definitions is small.…”

Section: A Heave Motion Componentsmentioning

confidence: 99%

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Effects of Heave Washout Settings in Aircraft Pitch Disturbance Rejection

Pool

Zaal

Paassen

et al. 2010

Journal of Guidance, Control, and Dynamics

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In most moving-base flight simulators, the simulated aircraft motion needs to be filtered with motion washout filters to keep the simulator within its limited motion envelope. Translational motion in particular requires filtering, as the low-frequency components of the vehicle motion tend to quickly drive simulators toward their motion bounds. Commonly, linear washout filters are therefore used to attenuate the simulated motion in magnitude and in phase. It is found in many studies that the settings of these washout filters affect pilot performance and control behavior. In most of these studies, no comparison to a case with one-to-one motion cues is performed as a result of the limited motion envelope of the simulators used. In the current study, an experiment was performed in the SIMONA Research Simulator at the Delft University of Technology to investigate the effects of heave washout settings on pilot performance and control behavior in a pitch attitude control task. In addition to rotational pitch motion, heave accelerations at the pilot station that result directly from aircraft pitch were evaluated. This heave motion component could be supplied one-to-one in the simulator due to the modest size of the aircraft model, a Cessna Citation I business jet. The experiment revealed that pilot performance and control activity both increased significantly with increasing heave motion fidelity. An analysis of pilot control behavior using pilot models indicated that the enhanced performance was caused by an increase in the magnitude with which pilots responded to visual and physical motion stimuli and a decrease in the amount of visual lead that was generated by the pilots. Nomenclature A = sinusoid amplitude, deg a z cg = c.g. heave acceleration, m s 2 a z = pitch-heave acceleration, m s 2 e = tracking error signal, deg f d = disturbance forcing function, deg f t = target forcing function, deg H nm = neuromuscular system dynamics H ol = open-loop response H sc = semicircular canal dynamics H p e = pilot visual response H p az = pilot heave motion response H p = pilot pitch motion response Hj! = frequency response function Hs = transfer function H ; e = controlled system dynamics j = imaginary unit, -K = gain, -K m = motion perception gain, -K v = visual perception gain, -k = sinusoid index, -l = pitch-heave arm length, m N = number of points, -n = forcing function frequency integer factor, -S = power spectral density s = Laplace variable T I = visual lag time constant, s T L = visual lead time constant, s T sc 1 , T sc 2 , T sc 3 = semicircular canal model time constants, s t = time, s u = pilot control signal, deg z = vertical position, m Symbols e = elevator deflection, deg = damping factor, -nm = neuromuscular damping, -= pitch angle, deg 2 = variance m = motion perception time delay, s v = visual perception time delay, s = sinusoid phase shift, rad ' m = phase margin, deg ! = frequency, rad s 1 ! c = crossover frequency, rad s 1 ! nm = neuromuscular frequency, rad s 1 ! sp = short period frequency, rad s 1 Subscri...

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Section: A Heave Motion Componentsmentioning

confidence: 99%

“…The combination of heave filter break frequency and gain that was used for the experiment described in [11] is depicted by condition F0.6. Heave filter F1.0 has the same break frequency as used for F0.6 but has unity gain.…”

Section: Independent Variablesmentioning

confidence: 99%

Effects of Heave Washout Settings in Aircraft Pitch Disturbance Rejection

Pool

Zaal

Paassen

et al. 2010

Journal of Guidance, Control, and Dynamics

View full text Add to dashboard Cite

show abstract

“…It is recommended in MIL-STD-1797B 6 and WL-TR-97-3100, 12 and is widely used in handling-qualities research studies (e.g., Ref. 25,Ref. 26,Ref.…”

Section: Offset Precision Landingmentioning

confidence: 99%

Handling Qualities Flight Test Assessment of a Business Jet N _zU P-β Fly-By-Wire Control System

Berger

Tischler

Hagerott³

et al. 2017

AIAA Atmospheric Flight Mechanics Conference

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Fly-by-wire control laws for a business jet were developed and a handling qualities assessment flight test was conducted on the Calspan Variable Stability System Learjet-25. The control laws, which provide an nzu-command response type in the longitudinal axis and a p-β-command response type in the lateral/directional axes, were optimized to meet Level 1 requirements for a comprehensive set of stability, handling qualities, and performance specifications. The control laws were evaluated in flight by USAF Test Pilot School and Textron Aviation test pilots using a series of handling qualities demonstration maneuvers. These included pitch and roll capture and tracking tasks and an offset landing task. Quantitative performance metrics were collected, in addition to pilot handling qualities ratings and comments. Several modifications were made to the control laws based on initial pilot comments and ratings. The final results show that the optimized fly-by-wire control laws provided assigned Level 1 handling qualities for discrete tracking and offset landing tasks.

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“…(PH). As explained in detail by Field et al, 27 for a conventional aircraft the pitch rotation that occurs upon a longitudinal column input does not occur around the aircraft center of gravity, but rather around a location commonly referred to as the instantaneous center of rotation (ICR), which is typically located closer to the pilot station than the aircraft c.g. By definition, the ICR is the longitudinal along the aircraft longitudinal axis that does not initially move in vertical direction upon a step pitch control input.…”

Section: Iiic Heave Responsementioning

confidence: 99%

Effects of Heave Washout Filtering on Motion Fidelity and Pilot Control Behavior for a Large Commercial Airliner

Wieringen

Pool

Paassen

2011

AIAA Modeling and Simulation Technologies Conference

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Due to the significant translational heave motion at the pilot station associated with changes in aircraft pitch attitude, the motion cueing for aircraft pitch maneuvering typically requires significant heave washout filtering. Previous studies that attempted to motivate choices in the motion cueing strategy for pitch maneuvering based on measurements of pilot behavior. For the small conventional aircraft considered in these studies, the results indicated that, despite the fact that pilots were found to adapt their control strategy to changes in heave cueing, the pitch rotation had a dominant influence on pilot behavior during pitch tracking. For large commercial airliners, a relevant application of this research as a lot of commercial pilot training occurs on moving-base simulators, the location of the pilot station is significantly further from the center of aircraft pitch rotation, yielding more pronounced heave motion cues during changes in pitch attitude. This difference, in addition to typically slower pitch dynamics that require more lead equalization, implies the best choice in motion cueing for large aircraft may be significantly different from what would be optimal for smaller aircraft. In this paper, an experiment is described in which pilot behavior is measured in a pitch attitude disturbance-rejection task with a controlled element and motion cueing conditions that are representative for a Boeing 747 aircraft. Different third-order heave washout filter settings were considered, in addition to a variation in the presence of 1-to-1 rotational pitch motion. Significant effects of the applied variation in pitch and heave motion cueing are observed, even though the effect of heave motion feedback is indeed found to be comparatively more important for larger aircraft. Furthermore, a heave motion filter that combined a low gain with low filter phase distortion was found to yield the least effect on pilot behavior, while for heave motion filters with a relatively high gain and high break frequency significantly larger contributions of motion feedback to pilot behavior were observed.

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Effects of Pitch Instantaneous Center of Rotation Location on Flying Qualities

Cited by 9 publications

References 1 publication

Effects of Heave Washout Settings in Aircraft Pitch Disturbance Rejection

Effects of Heave Washout Settings in Aircraft Pitch Disturbance Rejection

Handling Qualities Flight Test Assessment of a Business Jet N _zU P-β Fly-By-Wire Control System

Effects of Heave Washout Filtering on Motion Fidelity and Pilot Control Behavior for a Large Commercial Airliner

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Effects of Pitch Instantaneous Center of Rotation Location on Flying Qualities

Cited by 9 publications

References 1 publication

Effects of Heave Washout Settings in Aircraft Pitch Disturbance Rejection

Effects of Heave Washout Settings in Aircraft Pitch Disturbance Rejection

Handling Qualities Flight Test Assessment of a Business Jet N zU P-β Fly-By-Wire Control System

Effects of Heave Washout Filtering on Motion Fidelity and Pilot Control Behavior for a Large Commercial Airliner

Contact Info

Product

Resources

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Handling Qualities Flight Test Assessment of a Business Jet N _zU P-β Fly-By-Wire Control System