Study On Structure Optimization And Semi-Active Control Of New Hydro-Pneumatic Inerter-Based Suspension

As a new type of mechanical component,inerter has been widely studied in many engineering fields involving vibration isolation due to its good low-frequency vibration isolation performance,especially in the field of automotive vibration isolation.However,the high-frequency vibration isolation performance of inertial vessels is not ideal.Therefore,the development of controllable inerter technology and how to match it to the automobile suspension have become a new topic in the field of automobile.A new type of hydro-pneumatic inerter-based suspension system is designed in this paper based on the structure and performance characteristics of hydraulic inerter and hydropneumatic suspension,and conducts parameter optimization design and semi-active control research on it.In this paper,parameter optimization design and semi-active control research on the new suspension system are carried out.Through simulation and experiments,the comprehensive performance of the suspension system and the feasibility of its spatial arrangement are analyzed.The results show that the new hydro-pneumatic inerter-based suspension proposed in this paper can effectively suppress the vibration intensity of the human body’s sensitive vibration frequency band,and can effectively ensure the grounding of the tires.That means it can coordinate the contradiction between vehicle ride comfort and stability.This research lays the theoretical and practical foundation for the research of inerter in the field of vehicle vibration isolation.The main research contents are as follows:Firstly,the nonlinear mathematical model of the new hydro-pneumatic inerter-based suspension is established according to its working principle.And analyze the influencing factors of the suspension output force characteristics through simulation.On this basis,the main parameters that affect the suspension performance are condensed.Furthermore,the validity of the model is verified by the external characteristic test of the suspension,which provides a theoretical basis for further research.Secondly,according to the 1/4 model of the hydro-pneumatic inerter-based suspension in the basic state,combined with the vehicle vibration theory and international ISO standards,the sequential quadratic programming method is used to optimize the important structural parameters of the hydro-pneumatic inerter-based suspension designed in this paper.The simulation results show that the body acceleration,the suspension working space and the dynamic tire load of the hydro-pneumatic inerter-based suspension optimized are reduced by19.6%,21.4% and 10.2% respectively.Therefore,the optimization effect is relatively ideal.Thirdly,research on semi-active control of the hydro-pneumatic inerter-based suspension system is carried out.By linearization and equivalence processing,the nonlinear model of the suspension can match the linear control theory.At the same time,based on the LQG optimal control theory,the framework of the LQG controller is built,and various important parameters of the controller are optimized through genetic algorithm.Then select the semi-active hydro-pneumatic suspension with skyhook control strategy as the comparison target,and the semi-active hydro-pneumatic inerter-based suspension designed in this paper is compared and analyzed in the time domain and frequency domain through the AMESim simulation software.The results show that under the bump road input,the semi-active hydropneumatic inerter-based suspension can effectively reduce the peak-to-peak value of each dynamic response;under the random road input,the performance indexes of the semi-active hydro-pneumatic inerter-based suspension are improved to different extents compared with the ordinary semi-active hydro-pneumatic suspension.Finally,the hardware-in-the-loop test of the semi-active hydro-pneumatic inerter-based suspension was carried out.With the semi-active hydro-pneumatic suspension with skyhook control strategy as the comparison object,the sinusoidal input test and the random input test were carried out respectively to verify the performance of the new suspension.Sinusoidal input tests under different frequencies show that the body acceleration of the semi-active hydro-pneumatic inerter-based suspension has a significant optimization effect in the range of 6 Hz ～ 15 Hz,while the tire dynamic load is optimized significantly in the range of 9 Hz～ 15 Hz.although the suspension working space is slightly deteriorated in the range of 2 Hz～ 5 Hz,but there is a certain optimization effect in other frequency ranges.The random input tests under the B-class road show that the semi-active hydro-pneumatic inerter-based suspension at the vehicle speed of 30km/h,40km/h,and 50km/h has optimized the RMS value of the body acceleration by 14.9%,21.4%,and 28.3% respectively;the suspension working space has been optimized by 7.7%,10.5%,10.0%;tire dynamic load was optimized by 11.3%,12.1%,11.9%.In addition,the suspension system has a compact structure and flexible space layout,which is conducive to project implementation.