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dc.rights.licenseRestricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.
dc.contributorGandhi, Farhan
dc.contributorJulius, Anak Agung
dc.contributorHicken, Jason
dc.contributorMishra, Sandipan
dc.contributor.authorReddinger, Jean-Paul Francis
dc.date.accessioned2021-11-03T08:51:06Z
dc.date.available2021-11-03T08:51:06Z
dc.date.created2017-07-27T09:37:44Z
dc.date.issued2017-08
dc.identifier.urihttps://hdl.handle.net/20.500.13015/2005
dc.descriptionAugust 2017
dc.descriptionSchool of Engineering
dc.description.abstractA 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.
dc.description.abstractA 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.
dc.description.abstractA 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.
dc.language.isoENG
dc.publisherRensselaer Polytechnic Institute, Troy, NY
dc.relation.ispartofRensselaer Theses and Dissertations Online Collection
dc.subjectAeronautical engineering
dc.titlePerformance, vibrations, and survivability of a compound helicopter with control redundancy
dc.typeElectronic thesis
dc.typeThesis
dc.digitool.pid178424
dc.digitool.pid178425
dc.digitool.pid178426
dc.rights.holderThis electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
dc.description.degreePhD
dc.relation.departmentDept. of Mechanical, Aerospace, and Nuclear Engineering


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