This paper describes an analytical investigation into synchrophasing,a vibration control strategy on a machinery installation in which two rotational machines are attached to a beam-like raft by discrete resilient iso...This paper describes an analytical investigation into synchrophasing,a vibration control strategy on a machinery installation in which two rotational machines are attached to a beam-like raft by discrete resilient isolators.Forces and moments introduced by sources are considered,which effectively represent a practical engineering system.Adjusting the relative phase angle between the machines has been theoretically demonstrated to greatly reduce the cost function,which is defined as the sum of velocity squares of attaching points on the raft at each frequency of interest.The effect of the position of the machine is also investigated.Results show that altering the position of the secondary source may cause a slight change to the mode shape of the composite system and therefore change the optimum phase between the two machines.Although the analysis is based on a one-dimensional Euler– Bernoulli beam and each machine is considered as a rigid-body,a key principle can be derived from the results.However,the factors that can influence the synchrophasing control performance would become coupled and highly complicated.This condition has to be considered in practice.展开更多
Turboprop engine has the advantages of high efficiency and high thrust, but it has not been widely used in the civil field because of the noise excited by the low speed propellers. Propeller synchrophasing control is ...Turboprop engine has the advantages of high efficiency and high thrust, but it has not been widely used in the civil field because of the noise excited by the low speed propellers. Propeller synchrophasing control is an active noise control method without increasing the weight of the airframe, which can attenuate the noise level in the cabin by controlling the relative phase among multiple propellers. It is generally accepted that altitude and airspeed have a great influence on the noise reduction effect of propeller synchrophasing, but there is no theoretical research about how these two factors affect the noise level. Therefore, flight experiment is considered to be a credible way. However, flight experiments of propeller synchrophasing control in turboprop aircraft have been accomplished in few countries due to enormous cost and inconvenience. An experimental platform of synchrophasing control based on a two-propeller small unmanned air vehicle(UAV) is proposed which can carry out the flight experiment research in a low-cost way. The phase angle sensor, the FOC-based scheme of motor driving, the all-slave synchrophasing control and the coordination between speed and phase difference control are presented in the UAV platform to meet its synchrophasing control precision requirement, experimental results prove that all of them can significantly enhance the performance of synchrophasing control. Noise characteristics of propellers are studied in the flight experiments, the noise predicted by the noise model is highly consistent with the actual measured noise, which verifies that the noise characteristics of small UAV accord with propeller signature theory. Based on the noise model, propeller synchrophasing has a steady effect to minimizing noise in the UAV platform. These show that the UAV platform is a feasible solution for propeller synchrophasing research.展开更多
文摘This paper describes an analytical investigation into synchrophasing,a vibration control strategy on a machinery installation in which two rotational machines are attached to a beam-like raft by discrete resilient isolators.Forces and moments introduced by sources are considered,which effectively represent a practical engineering system.Adjusting the relative phase angle between the machines has been theoretically demonstrated to greatly reduce the cost function,which is defined as the sum of velocity squares of attaching points on the raft at each frequency of interest.The effect of the position of the machine is also investigated.Results show that altering the position of the secondary source may cause a slight change to the mode shape of the composite system and therefore change the optimum phase between the two machines.Although the analysis is based on a one-dimensional Euler– Bernoulli beam and each machine is considered as a rigid-body,a key principle can be derived from the results.However,the factors that can influence the synchrophasing control performance would become coupled and highly complicated.This condition has to be considered in practice.
基金supported by the National Natural Science Foundation of China(Grant No.51576097)
文摘Turboprop engine has the advantages of high efficiency and high thrust, but it has not been widely used in the civil field because of the noise excited by the low speed propellers. Propeller synchrophasing control is an active noise control method without increasing the weight of the airframe, which can attenuate the noise level in the cabin by controlling the relative phase among multiple propellers. It is generally accepted that altitude and airspeed have a great influence on the noise reduction effect of propeller synchrophasing, but there is no theoretical research about how these two factors affect the noise level. Therefore, flight experiment is considered to be a credible way. However, flight experiments of propeller synchrophasing control in turboprop aircraft have been accomplished in few countries due to enormous cost and inconvenience. An experimental platform of synchrophasing control based on a two-propeller small unmanned air vehicle(UAV) is proposed which can carry out the flight experiment research in a low-cost way. The phase angle sensor, the FOC-based scheme of motor driving, the all-slave synchrophasing control and the coordination between speed and phase difference control are presented in the UAV platform to meet its synchrophasing control precision requirement, experimental results prove that all of them can significantly enhance the performance of synchrophasing control. Noise characteristics of propellers are studied in the flight experiments, the noise predicted by the noise model is highly consistent with the actual measured noise, which verifies that the noise characteristics of small UAV accord with propeller signature theory. Based on the noise model, propeller synchrophasing has a steady effect to minimizing noise in the UAV platform. These show that the UAV platform is a feasible solution for propeller synchrophasing research.
