Design And Research Of Load Adaptive Vibration Isolation System Based On Quasi-zero Stiffness Characteristics

With the development of China’s economy,maritime transportation and shipping have played an important role in cargo transportation.Its advantages such as low price and huge carrying capacity have made it the main mode of transportation in international trade.During the course of the ship’s voyage,its speed is determined by the propulsion force,and the thrust is formed through the rotation of the propeller and transmitted to the submarine through the thrust bearing.There is longitudinal vibration of shafting on the propeller shaft connected by propeller.Adding shafting longitudinal vibration isolator can reduce the vibration of the shaft under a constant propulsion force,but it cannot solve the vibration effect after the change of propulsion force.In view of this problem,based on the vibration isolation performance of the quasi-zero stiffness vibration isolation system and the adjustment ability of the control system,this paper studies and builds a new type of vibration isolator of high-precision vibration isolation structure with load adaptive capacity to solve the problem that the load mass changes in the vibration isolation process of the isolator.Professor Qingjie Cao of Harbin industrial university in 2006,according to geometric nonlinear characteristics of SD oscillator theory,established a new type of adaptive system with load combination of quasi zero stiffness characteristics of high precision vibration isolation model.We combined theoretical derivation under simple harmonic excitation,numerical calculation and the virtual prototype simulation to validate the model.According to the result of the argument,they designed a new type of high precision with load adaptive characteristics quasi zero stiffness of isolation system.The main contents of this paper are as follows:First,based on the SD oscillator theory,a theoretical model of a new type model of load adaptive vibration isolation was established.The establishment conditions of the model and the dynamic equation were analyzed.The parameter ratio of quasi-zero stiffness was obtained.The amplitude-frequency and force-transfer characteristics of the system under simple harmonic excitation are derived and analyzed by means of the average method.Meanwhile,the effects of different parameters on the amplitudefrequency and force-transfer characteristics of the system are analyzed.Secondly,according to the design requirements of the load adaptive system and the design process of the system,the method of distinguishing the varying static load and dynamic load in the actual vibration situation is explored to improve the design thinking of the load adaptive system.According to the position,torque and other parameters of the new quasi-zero stiffness isolator,the hardware needed in the system is selected,and the load adaptive system is built to solve the problem of load mass change in the vibration process.We established adaptive system with a load of quasi zero stiffness vibration isolation system.Simulation analysis of quasi zero stiffness vibration isolation system under the condition of not adding load adaptive system and the vibration isolation effect of added load adaptive system quality change after different forms,different sampling parameters,different threshold filter frequency vibration isolation system under the circumstance of the response.The response output of the system under different conditions was compared and analyzed,and the optimal parameters were selected for detailed analysis to verify the vibration isolation capability of the load adaptive quasi-zero stiffness vibration isolation system.