Zhao, Xiaonan (2016)
Transmission of Vibration Caused by Unbalance in an Aircraft Engine with Active Control Strategies.
Buch, Erstveröffentlichung
Kurzbeschreibung (Abstract)
This work was initiated by the ideas of employing active systems inside the aircraft engine to actively reduce the vibration transmitted from the engine into the fuselage. Focusing on the vibration caused by the rotor unbalance and the comfort inside the fuselage, potential positions for actuators were identified along the vibration transmission path from the rotor to the fuselage: (1) at the bearing of the rotor, (2) inside the struts or along the links of the internal suspension of the engine, and (3) along the links of the mount system between the engine and the fuselage.
A finite element reference model of a twin-spool engine attached to a section of the fuselage was investigated. To evaluate the active systems with these three actuator placement approaches, a model generation procedure was developed and state space models of different bearing configurations were created from this model. Three suspension systems were defined according to these actuation approaches, and their performances and different control strategies were compared based on the optimization results, which were generated in the frequency domain by minimizing different cost functions. The results were presented in terms of the average mechanical power transmitted through the suspension, indicating the vibrational energy emitted into the receiver structure. It was found that a good reduction level could be achieved, when the first approach was applied (12.4 dB during the cruise) or the current passive damping technique at the rotors, namely, squeeze film dampers, worked together with the other two approaches (5.0 dB with the second approach and 10.3 dB with the third). Subsequently, several control algorithms were investigated on four active systems: three systems corresponding to the three actuation approaches in which actuators and sensors were collocated and one system with the second approach controlling the vibration on the fuselage. FxLMS proved to be capable to realize the ideal effectiveness, except for the collocated system with the second approach, under the condition of an accurate estimation of the secondary path. This algorithm was robust to an amplitude error of the secondary path model, and a phase error up to ca. 20% during the cruise, for example, could be tolerated with a compromise of ca. 3 dB less reduction. Worse stability arose with the increase of the phase error, and thus required smaller step sizes and resulted in slower converging speed. It was easy to find the optimal gain of an IFF controller, even if it was applied in such a large and complex system, due to its advantage of unconditional stability in collocated systems.
These conclusions based on numerical results were discussed and most of them were verified by comparing them with those in past studies, in which the same methods were applied or similar systems were under investigation. At the end, suggestions were given for the selection and packaging of actuators, the selection and placement of sensors and the implementation of controllers.
Typ des Eintrags: | Buch | ||||
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Erschienen: | 2016 | ||||
Autor(en): | Zhao, Xiaonan | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Transmission of Vibration Caused by Unbalance in an Aircraft Engine with Active Control Strategies | ||||
Sprache: | Englisch | ||||
Referenten: | Rinderknecht, Prof. Dr. Stephan ; Schweizer, Prof. Dr. Bernhard | ||||
Publikationsjahr: | 2016 | ||||
Ort: | Darmstadt | ||||
Datum der mündlichen Prüfung: | 14 Oktober 2015 | ||||
URL / URN: | http://tuprints.ulb.tu-darmstadt.de/5361 | ||||
Kurzbeschreibung (Abstract): | This work was initiated by the ideas of employing active systems inside the aircraft engine to actively reduce the vibration transmitted from the engine into the fuselage. Focusing on the vibration caused by the rotor unbalance and the comfort inside the fuselage, potential positions for actuators were identified along the vibration transmission path from the rotor to the fuselage: (1) at the bearing of the rotor, (2) inside the struts or along the links of the internal suspension of the engine, and (3) along the links of the mount system between the engine and the fuselage. A finite element reference model of a twin-spool engine attached to a section of the fuselage was investigated. To evaluate the active systems with these three actuator placement approaches, a model generation procedure was developed and state space models of different bearing configurations were created from this model. Three suspension systems were defined according to these actuation approaches, and their performances and different control strategies were compared based on the optimization results, which were generated in the frequency domain by minimizing different cost functions. The results were presented in terms of the average mechanical power transmitted through the suspension, indicating the vibrational energy emitted into the receiver structure. It was found that a good reduction level could be achieved, when the first approach was applied (12.4 dB during the cruise) or the current passive damping technique at the rotors, namely, squeeze film dampers, worked together with the other two approaches (5.0 dB with the second approach and 10.3 dB with the third). Subsequently, several control algorithms were investigated on four active systems: three systems corresponding to the three actuation approaches in which actuators and sensors were collocated and one system with the second approach controlling the vibration on the fuselage. FxLMS proved to be capable to realize the ideal effectiveness, except for the collocated system with the second approach, under the condition of an accurate estimation of the secondary path. This algorithm was robust to an amplitude error of the secondary path model, and a phase error up to ca. 20% during the cruise, for example, could be tolerated with a compromise of ca. 3 dB less reduction. Worse stability arose with the increase of the phase error, and thus required smaller step sizes and resulted in slower converging speed. It was easy to find the optimal gain of an IFF controller, even if it was applied in such a large and complex system, due to its advantage of unconditional stability in collocated systems. These conclusions based on numerical results were discussed and most of them were verified by comparing them with those in past studies, in which the same methods were applied or similar systems were under investigation. At the end, suggestions were given for the selection and packaging of actuators, the selection and placement of sensors and the implementation of controllers. |
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URN: | urn:nbn:de:tuda-tuprints-53611 | ||||
Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 600 Technik, Medizin, angewandte Wissenschaften > 600 Technik | ||||
Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Institut für Mechatronische Systeme im Maschinenbau (IMS) |
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Hinterlegungsdatum: | 17 Apr 2016 19:55 | ||||
Letzte Änderung: | 29 Mai 2016 21:19 | ||||
PPN: | |||||
Referenten: | Rinderknecht, Prof. Dr. Stephan ; Schweizer, Prof. Dr. Bernhard | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 14 Oktober 2015 | ||||
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