Comprehensive Investigation On Active-passive Hybrid Isolation And Tunable Dynamic Vibration Absorption

Researchs on noise and vibration control for submarine have been attracted a great deal of attention.Sound caused by machine,hydrodynamic and propeller are three major noise sources in vessels.Hydrodynamic and propeller noise are coverd by mechanical noise when vessels sail in low-middle speed.As a result,control of machines and piping's noise plays a key role in realizing vessels' stealth.Traditional measures to control vibration and noise are not applicable in controlling low frequency vibration and noise because of physical limitations.While active control is feasible for this through introducing external energy or changing characters adaptively such as stiffness or damping.This paper tried to control diesel and piping's vibration with active-passive hybrid isolation and tunable dynamic vibration absorption techniques so as to reduce vibration transmitted through base or other supporting sets to hull or deck.Habach array was used to research active-passive hybrid isolation technique.Isolators developed by this new magnetic array could be much smaller and lighter than those by normal maget with the same output force requirement.What's more,digital power amplify technique was researched.This kind of amplifier has far less weight,dimension and radiates much less energy.Thereby increase the applicable capabilities in engeering.Then Leaky-LMS algorithm was adapted basesd on Genetic Algorithm to overcome its filters' coeffcients overflow problem so as to improve control algorithm's steady and control effection.The results of single frequency isolation test showed that 11 d B isolation effect was achieved by active-passive hybrid method compared with passive method.Targeted at WD618 diesel's vibration character,adaptive feed-forward control stratigy was developed.And decentralized feedforward control hardware was researched.The test of diesel isolation in realization showed that the vibration of base reduced substantially under 70 Hz,about 4d B more than that of passive isolation.And the vibration of deck reduced about 7d B more than that of passive isolation under 100 Hz.Design method about 3 degree-of-freedom dynamic vibration absorption was developed based on piping's dynamic behavior.Then 3 degree-of-freedom adaptive absorber was designed.Tunable frequency domain of 40 Hz,17Hz and 50 Hz could be acquired respectively in X,Y and Z directions.The control stratigy based on machine learning used to tune absorber's natural frequency could reduce system's tuning time and keep high operation precision.Apply this original adaptive absorber to tipical submarine piping,6d B vibration reduction could be acquired in three directions.Vibration of other frequencies was also attenuated,in which 9d B vibration reduction was achieved at most.Frequency band of low frequency was reduced about 3d B as well.The vibration of hull decreased slightly in correspongding frequencies,in which 15 d B vibration absorption could be watched at 250 Hz.