Simulation Study On Adaptive Vibration Isolation Of Car Seat Load Based On The Mechanical Characteristics Of Air Spring

Automobiles are playing an increasingly important role in people’s lives.With the improvement of the quality of life and the development of the automobile industry,people have put forward higher requirements for the comfort of vehicles.Being in a lowfrequency vibration environment for a long time will make people sore back and spine,so low-frequency vibration isolation is a problem that must be solved in the car.In recent years,domestic and foreign scholars have proposed many high-static and low-dynamic quasi-zero stiffness seat suspensions,but most of them are not suitable for changing loads.Based on the SD vibrator theory proposed by Professor Qingjie Cao of Harbin Institute of Technology in 2006,and combined with the adjustable stiffness characteristics of air springs,this paper proposes a quasi-zero stiffness automobile seat suspension with load adaptive adjustment function.Firstly,establish the mechanical model of the air spring.In order to simplify the calculation,rationally simplify the theory,put forward the hypothesis that the effective area is basically constant,test its rationality through experiments,and give the method and initial conditions to control the effective area change rate within 5%,and finally verify the correctness of the entire theory.Secondly,air springs are used to establish a new type of quasi-zero stiffness vibration isolator,and the negative stiffness characteristics and system stiffness characteristics are studied.Solve the response of the system under simple harmonic excitation,conduct amplitude-frequency response analysis,analyze the influence of main parameters damping and excitation amplitude on the amplitude-frequency response curve.Solve the system transfer rate,and analyze the influence of the main parameters damping and excitation amplitude on the transfer rate.Then use the SIMPACK multi-body dynamics simulation software to use the air spring force and displacement data obtained from the experiment for dynamic simulation,and compare it with the quasi-zero stiffness vibration isolator of the traditional coil spring structure to inspect whether the quasi-zero stiffness vibration isolator constructed by the air spring has the characteristics of high static and low dynamic quasi-zero stiffness.The simulation and comparison of the vibration isolation effect of the seat without offset,offset of 1cm and offset of 2cm illustrate the necessity of adaptive load adjustment.The simulation and comparison of the vibration isolation effect when the human body weight is 50 kg,70kg and 90 kg show that the new quasi-zero stiffness vibration isolator has a good load adaptive adjustment function.Finally,the realization mechanism of load adaptive adjustment is explained,the flow chart of using PID control method to adjust the height of the system is given,and the influence of temperature on the stiffness of the air spring is discussed,and how to configure the stiffness at different temperatures to make the system have Quasi-zero stiffness characteristics.When the temperature is higher than 10℃,the stiffness can be configured directly through the air pressure relationship.When the temperature is lower than 10°C,air springs can be regarded as linear springs,use the quasi-zero stiffness condition of the traditional quasi-zero stiffness isolator to configure the stiffness,and query the relationship data between the stiffness of the air spring and the initial air pressure and the initial height obtained through experiments to find the initial air pressure of the vertical and horizontal air springs.