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Performance, Vibrations, and Survivability of a Compound Helicopter with Control Redundancy.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Performance, Vibrations, and Survivability of a Compound Helicopter with Control Redundancy./
Author:	Reddinger, Jean-Paul Francis.
Description:	1 online resource (227 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
Contained By:	Dissertation Abstracts International79-01B(E).
Subject:	Aerospace engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9780355115970

Performance, Vibrations, and Survivability of a Compound Helicopter with Control Redundancy.
Reddinger, Jean-Paul Francis.

Performance, Vibrations, and Survivability of a Compound Helicopter with Control Redundancy. - 1 online resource (227 pages)

Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

A fully compounded helicopter includes the full set of controls present on a conventional helicopter (collective, longitudinal cyclic, lateral cyclic, and tail rotor pitch) in addition to fixed-system control surfaces (stabilator pitch and differential ailerons) and compound-specific auxiliary controls (propeller thrust and main rotor speed). The control redundancy allows an infinite number of potential steady-state trimmed flight conditions, over which the controls can be optimized to achieve a target such as low power. Using a rigid blade analysis with linear inflow, parametrically varied trim states are examined in detail to extract the relevant physical phenomena and corresponding rotor aeromechanics of the minimum power trim states at 225 kts. An elastic blade model with prescribed wake inflow modeling is developed to examine blade loads and rotor vibrational characteristics. Important design considerations such as blade twist are considered by comparing -8° linearly twisted blades and untwisted blades. The minimum power and vibration states corresponded to different redundant control settings and main rotor behavior for the twisted blade, but for the untwisted blade, the settings for minimum power and vibrations are similar.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9780355115970Subjects--Topical Terms:

686400
Aerospace engineering.
Index Terms--Genre/Form:

554714
Electronic books.

Performance, Vibrations, and Survivability of a Compound Helicopter with Control Redundancy.
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100 1 $a Reddinger, Jean-Paul Francis. $3 1179221
245 1 0 $a Performance, Vibrations, and Survivability of a Compound Helicopter with Control Redundancy.
264 0 $c 2017
300 $a 1 online resource (227 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
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500 $a Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
500 $a Adviser: Farhan Gandhi.
502 $a Thesis (Ph.D.) $c Rensselaer Polytechnic Institute $d 2017.
504 $a Includes bibliographical references
520 $a A fully compounded helicopter includes the full set of controls present on a conventional helicopter (collective, longitudinal cyclic, lateral cyclic, and tail rotor pitch) in addition to fixed-system control surfaces (stabilator pitch and differential ailerons) and compound-specific auxiliary controls (propeller thrust and main rotor speed). The control redundancy allows an infinite number of potential steady-state trimmed flight conditions, over which the controls can be optimized to achieve a target such as low power. Using a rigid blade analysis with linear inflow, parametrically varied trim states are examined in detail to extract the relevant physical phenomena and corresponding rotor aeromechanics of the minimum power trim states at 225 kts. An elastic blade model with prescribed wake inflow modeling is developed to examine blade loads and rotor vibrational characteristics. Important design considerations such as blade twist are considered by comparing -8° linearly twisted blades and untwisted blades. The minimum power and vibration states corresponded to different redundant control settings and main rotor behavior for the twisted blade, but for the untwisted blade, the settings for minimum power and vibrations are similar.
520 $a A range of failed main rotor swashplate actuators (by piston impingement) are simulated in RCAS at hover, 100 kts, and 200 kts, to show the extent to which the compound effectors can generate additional forces and moments to maintain trimmed flight. After the loss of control of any of the three main rotor actuators in hover, the compound helicopter is capable of trimming for a small subset of servo positions by replacing control of the locked servo with control of rotor speed. At forward flight speeds, each of the three actuators produces a different result on the trimmed aircraft due to the non-axisymmetry of the rotor. Reconfiguration is accomplished through use of the ailerons, stabilator pitch, wings, and wing-mounted propellers, and the additional effectors with authority in forward flight increases the range of tolerable failures.
520 $a A knowledge-based concept for allocating the power minimum controls as an alternative to a Fly-to-Optimal approach is then considered. A predictive neural network is trained to be used as a surrogate model for a gradient based optimization to find the redundant control settings that produce a trim state with a minimized power requirement. When used appropriately, the models demonstrate the ability to allocate redundant controls such that the power requirement is within 1-3% of the true minimum power. A demonstration of using neural network models of main rotor actuation height shows how these surrogate modeling approaches can be used to allocated redundant controls to maintain trimmed flight to a pilot despite a pinned-in-place main rotor actuator failure.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Aerospace engineering. $3 686400
650 4 $a Mechanical engineering. $3 557493
655 7 $a Electronic books. $2 local $3 554714
690 $a 0538
690 $a 0548
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Rensselaer Polytechnic Institute. $b Aeronautical Engineering. $3 1179171
773 0 $t Dissertation Abstracts International $g 79-01B(E).
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10599717 $z click for full text (PQDT)