Integrated speed/synchrophasing control of turboprop engine

Abstract

Propeller synchrophasing control is an active method to reduce the noise and vibration of turboprop aircraft without additional weight and power. Phase control accuracy has a great influence on the noise reduction effect of synchrophasing. An integrated power/speed/synchrophasing control strategy is proposed to improve the control precision. Speed/phase control transformation logic based on a multi-blade phase plane is adopted which can take both the rapidity of speed response and phase control precision into account, but there exists switching oscillation during the mode transform process. In order to suppress the phase fluctuation due to exterior disturbance, a slave-slave control scheme is provided to take place of a master-slave scheme. Simulation results based on an integrated turboprop engine/propeller real-time non-linear model show that speed/phase integration logic can improve the response rapidity of both the speed and phase. The precision of the control system is verified to be in acceptable range.

Machine learning methods for liquid crystal research: phases, textures, defects and physical properties

“…[104][105][106] In a recent study, ML algorithm has been applied to the shear-sensitive liquid crystal coating (SSLCC) used for nonintrusive global wall shear stress measurements. 107 A feedforward back-propagation network predicted the magnitude and direction of shear by mapping the relationship between the SSLCC colors observed at different viewing angles and the corresponding wall shear stress vectors. In the case of a symmetrical flow field, even one image was enough to solve the shear stress vectors.…”

Research on Modeling of a Micro Variable-Pitch Turboprop Engine Based on Rig Test Data

“…A variety of micro turbojet engines have been developed. Rig tests of conventional aeroengine can only be carried out in a few research institutes, while the rig test of micro-engines can be carried out in the laboratory, with a low risk and cost; therefore, micro-engine rig tests can be used for verifying advanced control theory of aeroengines [5][6][7]. Advanced turboprop engines have two independent controlled variables, fuel flow, and propeller pitch angle, which makes it possible to keep the propeller rotating stably at variable speeds.…”

“…Advanced turboprop engines have two independent controlled variables, fuel flow, and propeller pitch angle, which makes it possible to keep the propeller rotating stably at variable speeds. Therefore, the turboprop engine can generate more power with fewer fuel consumption [7].…”