| Hydro-pneumatic suspension has non-linear stiffness and damping characteristics,which can meet the characteristics of emergency rescue vehicles with large mass and complex driving conditions.By obtaining the minimum vertical acceleration RMS value,the damping parameters at different speeds and road classes are optimized offline and the road class is identified to improve the riding comfort of emergency rescue vehicles.This article relies on the National Key R&D Program of China "Research and Application Demonstration of Key Technology of High-mobility Multi-function Emergency Rescue Vehicles"(No.2016YFC0802904),using emergency rescue vehicle hydro-pneumatic suspension system as the research object,the characteristics of the hydro-pneumatic suspension are analyzed,and the damping optimization method is proposed to improve the ride comfort of the vehicle.The specific research contents are as follows:(1)A mathematical model of hydro-pneumatic suspension is established and its mechanical characteristics are analyzed.Based on the knowledge of the ideal gas equation of state and fluid mechanics,the mathematical model of the hydro-pneumatic suspension is established combined with the suspension system structure and installation form.Based on the established mathematical model,its nonlinear stiffness and damping characteristics are analyzed,and the influence of each key parameter on its characteristics is studied.(2)A co-simulation model based on TruckSim and MATLAB/Simulink and a road simulation model based on white noise are developed.Based on the key parameters of the emergency rescue vehicle,a TruckSim vehicle model is created,and a suspension model and its control model are established in MATLAB / Simulink.Combined with the actual driving road conditions,various levels of white noise road models are established.The vehicle and axle responses are simulated and tested,and the analysis and comparison between the data verifies the rationality of the road model.(3)Based on vehicle riding comfort,offline damping parameter optimization and characteristic analysis of the suspension system are performed.Aiming at minimizing the root mean square value of the vertical acceleration of the vehicle body,the Kriging model and genetic algorithm are used to optimize the damping parameter of the suspension system.Then,the characteristics of the optimal solution with the change of vehicle speed and road level and the sensitivity of the damping change are analyzed.(4)Identify the road level based on the discriminant analysis method and optimize the damping parameter in real time based on this.The Fisher discriminant analysis method is used to identify the road level of the vehicle;based on the road level recognition result,the vehicle speed and offline suspension damping optimization result,the suspension damping is optimized in real time.The damping control method proposed in this paper and its research results lay a foundation and provide a reference for the next research of hydro-pneumatic suspension system of emergency rescue vehicles. |
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