DocumentCode :
3084367
Title :
Controlling transient deviations from adaptation lines in turbojet engine compressor fields via sliding mode
Author :
Tournes, Christian ; Shtessel, Yuri B.
Author_Institution :
Alabama Univ., Huntsville, AL, USA
fYear :
1997
fDate :
5-7 Oct. 1997
Firstpage :
791
Lastpage :
796
Abstract :
One possible approach to control turbofan engines is the use of high pressure and low pressure compressor field parameters. The adaptation line represents the locus of intermediate steady states between initial and final states. This is modeled to generate the smooth time varying compressor rates, mass flow rate and rotation rates of high pressure and low pressure compressors. Outer loop controls track the compression rates using the mass flow rates´ differences of operating points with adaptation conditions. High pressure and low pressure inner loops track prescribed mass flow rates using respectively the fuel mixture and the afterburner lid variable section area as controls. This allows the shaping of the transient trajectories, departing from and returning to the adaptation line. It allows safe operation, close to the stall and surging limits, thereby authorizing greater compressors´ accelerations during the transient. In order to overcome the complexity of the nonlinear plant representation and its uncertainty, output tracking in sliding mode is used. It is approximated by a smoothing sliding mode controller. A model of the adaptation line generates the time varying profiles of the high pressure and the fan compression rates associated with the adaptation line. This allows to shape the transient trajectories departing from the adaptation lines and returning to the adaptation lines at a steady state in the compressor fields. Thrust rate changes of a PW-F100 engine type are simulated. They show that both outer and inner loops of high pressure and low pressure spools are perfectly tracked.
Keywords :
acceleration control; aerospace control; aerospace engines; compressors; fuel; nonlinear control systems; position control; pressure control; time-varying systems; tracking; variable structure systems; PW-F100; accelerations; adaptation conditions; adaptation line transient deviation control; afterburner lid; fuel mixture; high pressure compressor field parameters; low pressure compressor field parameters; mass flow rate; nonlinear plant representation; operating points; rotation rates; sliding mode control; smooth time varying compressor rates; steady states; surging limits; thrust rate; time varying profiles; tracking; transient trajectories; turbojet engine compressor fields; uncertainty; Acceleration; Engines; Fuels; Incineration; Pressure control; Sliding mode control; Steady-state; Tracking loops; Uncertainty; Weight control;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Control Applications, 1997., Proceedings of the 1997 IEEE International Conference on
Conference_Location :
Hartford, CT, USA
Print_ISBN :
0-7803-3876-6
Type :
conf
DOI :
10.1109/CCA.1997.627757
Filename :
627757
Link To Document :
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