Research On Design And Control Of Magnetic-air Hybrid Vibration Isolation System Of Quasi-zero Stiffness

The traditional linear vibration isolation system only has the vibration isolation effect on the frequency band with more 2 times than the natural frequency.The Quasi-zero stiffness vibration isolation system has high dynamic and low static stiffness characteristics,which can solve this problem.When the system is under static load,the system has higher rigidity and can provide sufficient support force for the system;when the system is vibrated at static load,the system stiffness is approximately zero,and the vibration isolation bandwidth is expanded to achieve low frequency,ultra low frequency vibration isolation.At present,most of the vibration isolation systems based on quasi-zero stiffness theory have problems such as single object and narrow range of approximate zero stiffness.In order to solve this problem,combining with electromagnetic technology and air spring technology,a quasi-zero stiffness vibration isolation system is design in this paper.The air spring is used to adjust the positive stiffness and provide stable and variable static force for the whole system.Electromagnetic technology is used to adjust negative stiffness.When subjected to dynamic load,the whole system has nearly zero dynamic stiffness under the interaction of negative stiffness and positive stiffness.At the same time,a control strategy suitable for this vibration isolation system is proposed.The research mainly includes below:(1)Based on the analysis and summary of current electromagnetic technology and air spring technology,a double-symmetrical structure electromagnetic spring based on electromagnetic technology is designed,and the stiffness characteristic model of the electromagnetic spring is derived.The theoretical analysis and experiment are combined to derive the stiffness characteristic model of air spring.(2)According to the quasi-zero stiffness "parallel" structure theory,a magnetic-air hybrid vibration isolation system of quasi-zero stiffness is design and the system static model is established.The static analysis of the vibration isolation system without air spring and with air spring is carried out and the law between the electromagnetic spring parameters and the air spring parameters is researched.(3)The dynamic model of magnetic-air hybrid vibration isolation system of quasi-zero stiffness is established.The system's dimensionless amplitude-frequency characteristic equation is obtain using harmonic analysis method.The frequency hopping phenomenon and the influencing factors is analyzed in the amplitude-frequency characteristics.Finally,the force transfer rate and displacement transfer rate of the quasi-zero stiffness vibration isolation system are analyzed,and the corresponding transfer rate equation is obtained.(4)Based on the characteristics of magnetic-air hybrid vibration isolation system of quasi-zero stiffness,the control strategy system based on Type-2 fuzzy controller is design,and the quasi-zero stiffness characteristics of the vibration isolation system is analyzed by simulations;An experimental platform of magnetic-air hybrid vibration isolation system of quasi-zero stiffness is built and the experiment of system vibration isolation effects of top-down and bottom-up is carried out to analysis low frequency vibration isolation performance of the system.