Experimental Study On Active Control Of Longitudinal Vibration Of Propulsion Shafting

Submarine plays an important role in the defense of national sea area.Vibration and noise are a key reference index of submarine performance.The dynamic shafting of a submarine provides propulsion for the submarine.In this process,the longitudinal vibration of the shafting caused by the external exciting force exerts a great influence on the concealment and dynamic performance of the submarine.Therefore,the study of the longitudinal vibration control of the shafting is particularly critical.At present,the passive control is the most widely used method to control the longitudinal vibration of shafting,while the active control research is less,and most of them are still in the theoretical stage.In this thesis,aiming at the problem of longitudinal vibration control of shafting,starting from the active control of vibration,the application of piezoelectric materials in this field is explored.A test platform for active vibration control of shafting based on stacked piezoelectric actuators is built and experimental research is carried out.The details are as follows:(1)The physical model of shafting system is established,and the distributed parameter method and lumped mass method are introduced respectively.The shafting model is analyzed by these two methods,and the low-order natural frequencies,which play a major role in shafting vibration characteristics,are obtained.(2)An active control test platform based on piezoelectric material is designed,and a driving structure with piezoelectric actuator as the driving force is built.The active control method is introduced.The active control scheme based on classical control theory,which is the active control scheme based on PID algorithm,is proposed in this paper.The design of the whole experimental platform is described in detail,including the structure design of the active test platform and the design of the control system.(3)The simulation and experiment of the active control test platform based on piezoelectric materials are completed.Through the analysis of the vibration characteristics of the test platform,the system response relationship of the shafting system at the reference plane is deduced.By using MATLAB programming,the vibration reduction effect of the system is simulated and analyzed,and two frequency points withbetter vibration reduction effect are obtained,which are 161 HZ and 362 HZ respectively.According to the two frequencies obtained by simulation,fixed frequency excitation is carried out and active control experiments are completed respectively.The experimental results show that the effect of active control on reducing the longitudinal vibration of test platform can reach 16.6% and 28.2% respectively.Therefore,it can be known that the active control of longitudinal vibration of shafting based on PID algorithm has better effect.