Research On Vibration Isolation Performance Of Suspension Seat With Inerter

In order to solve the contradiction between reducing the natural frequency and ensuring the stiffness of the system in the design of the suspension seat,and further improving the comfort of the suspension seat,the inerter was applied to the suspension seat system.The research model of human-seat system were established because of the coupling motion between the human and the seat in the vibration environment.The seat bench test was carried out for the purpose of identifying the parameters of the suspension seat and the human model.Based on the vibration isolation performance evaluation index of the suspension seat,the vibration isolation performance of the two main vibration isolation structures were analyzed and compared.And based on the optimum isolation structure,a shear seat with an inerter was designed.In this paper,a suspension seat structure with a spring,a inerter and a damper is discussed,taking into account the suspension seat space constraints and the difficulty of project implementation and cost constraints.Two kinds of main ISD(inerter-spring-damper)vibration isolation structures are selected based on the series parallel connection of the spring,shock absorber and the inerter.The human body and the seat is a pair of coupled motion model,in order to study the dynamic response characteristics of the seat can’t be separated from the human body model.Therefore by combining with three degrees of freedom human body model(ISO 5982-2001),the four degrees of freedom Human-Seat systems were established.By means of shaking table experiment of suspension seat,the excitation and response acceleration signals are obtained.The transfer function curve of suspension seat human is obtained by the signal processing.Then,the model parameters are identified by using the transfer function curve and the theoretical model of the human chair system.The goodness of fit of the model is 98%.The dynamic responses of the models under different excitations,the influence of inertance on seat comfort and the matching relation between inertance and damping were analyzed,based on the evaluation index mean square value of weighted acceleration,the effective amplitude transmissibility and the maximum dynamic deflection.The results show that the use of the inerter in the suspension seat can significantly reduce the natural frequency of the system and improve the comfort of the seat.The parallel structure of the inerter,the spring and the damper is the most suitable structure for the suspension seat.The improvement degree of comfort and the optimal value of the inertance are all related to the excitation characteristics.The arrangement of the parallel structures of the inerter,the spring and the damper was analyzed in this paper,combining with the specific structure of the scissor seat.An inerter was applied to a scissor suspension seat to build ISD suspension seat.The differential equation of motion of the scissor seat was established,and the formulas for calculating the natural frequency,damping ratio,vibration transmissibility and dynamic deflection amplitude frequency characteristic of the vibration parameters were derived.The influence of the inertance and the seat structure parameters on the vibration characteristic parameters were analyzed.The results show that in a reasonable range,the larger the inertance,The larger the inclination angle of the integral structure of the damper and the inerter and the upper plate of the seat,the smaller the angle between the connecting rod and the seat base,the better the performance of vibration isolation.