Theoretical Model And Semi-active Damping Control Of Broadband Lever-type Vibration Isolatation

Mechanical vibration is the reciprocating motion of the system near its equilibrium position,which is harmful to most engineering applications and needs to be suppressed to reduce its impact on the main structure.Traditional linear vibration isolators have poor vibration isolation performance and narrow vibration isolation bandwidth.Nonlinear vibration isolators have the characteristics of high static stiffness and low dynamic stiffness,which can effectively broaden the vibration isolation bandwidth and reduce the vibration response.Therefore,they have received extensive attention.Damping is introduced to eliminate chaos and jumping caused by strong nonlinearity.Different from the traditional vibration isolators,this research carried out the theoretical model and semiactive control of broadband lever vibration isolation by introducing the lever structure to achieve high performance and broadband vibration isolation.The main contents of this paper include:1.A new type of broadband lever vibration isolator is designed.Based on the EulerLagrange equation,the motion differential equation of the vibration isolator is derived,and the amplitude frequency response function(FRF)is solved.The effect of the lever ratio,the mass at the end of the lever,lever material,cross-sectional area and other parameters on the vibration isolation performance and vibration isolation bandwidth are analyzed.The experimental system is designed to carry out the experimental research,and the experimental results verify the simulation analysis,which lays the foundation for the research of broadband lever vibration isolation.2.The effect of eddy current damping on the vibration isolation characteristics of broadband lever vibration isolator are studied.The theoretical model of eddy current damping is established,the control equation is derived and the amplitude frequency response function is obtained based on the harmonic balance method.The effect of the lever end mass,cross-sectional area,lever ratio and other parameters on the vibration isolation performance of the vibration isolator are analyzed.The experimental system is designed,and the experimental verification technology research is studied.The research results show that the lever vibration isolator can amplify the eddy current damping effect.Compared with the linear vibration isolator,the vibration isolation bandwidth and vibration isolation performance are greatly improved.This part of the work points out the direction for the design and optimization of the lever vibration isolator by studying the influence law of the parameters of the lever vibration isolator.3.A nonlinear magnetic stiffness lever vibration isolator is designed based on quasizero stiffness.Based on Ampere current model,the expression of nonlinear restoring force of vibration isolator is derived.The influence of geometric parameters between permanent magnets on the nonlinear restoring force and magnetic stiffness is analyzed.The model of nonlinear magnetic stiffness lever vibration isolator is established,and the the amplitude frequency response function is derived by the harmonic balance method.The effect of geometric parameters between permanent magnets,lever ratio,the mass at the end of the lever on the vibration isolation performance and vibration isolation bandwidth of the vibration isolator are studied.The experimental and simulation results show that the lever structure can further improve the vibration isolation performance of the quasi zero stiffness isolator,and the eddy current damping can eliminate the possible jumping phenomenon in the quasi-zero stiffness isolator.4.Research on semi-active control vibration isolation of lever vibration isolator is carried out.According to Kirchhoff law,the electric control equation of the electromagnetic branch circuit is derived,the dynamic model of the semi-active lever vibration isolation coupling system is established,the system response is solved,and the influence of negative resistance on the vibration isolation performance is studied.Research on the vibration isolation characteristics of semi-active lever vibration isolators is carried out.The results show that the negative resistance electromagnetic branch circuit can further reduce the vibration isolation performance of the lever vibration isolator,and the vibration isolation effect increases with the increase of the negative resistance.This paper provides a theoretical analysis and experimental verification method of broadband lever vibration isolator.The vibration isolation characteristics of broadband lever vibration isolator based on eddy current damping effect and nonlinear magnetic stiffness lever vibration isolator are studied.The design and parameter optimization of the lever vibration isolator are systematically analyzed,and the research on semi-active control of vibration isolator is studied based on branch circuit damping technology.The lever vibration isolator designed in this paper has the advantages of simple structure,excellent vibration isolation performance and wide vibration isolation bandwidth and can be applied to various vibration isolation control methods,so it has broad engineering application prospects.