The Design Of Displacement-sensitive Shock Absorber Based On Vehicle Ride Comfort

In nowadays, with the rapid development of science and technology, a high standardof living makes people focus on enjoying life. Automobile as a means of transport inour daily life, its good performance is common requirements of the automobilemanufacturers and consumers. Suspension as the main components reducing thevibration from road to the body, its performance is directly related to the comfort ofpassengers and integrity of the goods. One of the important components of vehiclesuspension is the shock absorber, it is installed with the elastic element in parallelwhich can absorb of the continuous vibration between the frame and body, as toreduce the vibration impact and improve vehicle ride comfort and safety. At present,the majority of our shock absorber manufacturer design a new shock absorber by the“experience&test” method, this method requires staff to continuously carry out theadjustment of sample and test, using this way need long time, a lot of manpower andmaterial resources, so it has low efficiency. Therefore, it is necessary to seek a newapproach, which regards the vehicle’s performance as the target, then use software tocreate the equivalent model for the shock absorber structural parameters, on this basis,using computer optimization techniques to recognize the damper structure parametersand trial production of the corresponding products. This method not only can savedevelopment costs, shorten the development cycle can also use the equivalent modelto guide the optimization and design of the damper structure. The purpose of thisstudy is to explore the feasibility and effectiveness of these methods.The car provided by OEMs mainly traveling in the state of no-load and full load, whatis more, the sprung mass of the car has a big change between full load condition andno-load condition, after discussions we ultimately determine to use an academicpatent of Konghui Guo-displacement-sensitive shock absorber as goals. Thedamping force of displacement-sensitive shock absorber is not only related to therelative velocity of the piston, but also related to the relative displacement of thepiston. Therefore, we can switch shock absorber damping according to the runningstate of the vehicle to achieve the purpose of improving vehicle ride comfort.This research work is divided into two parts:First, it is to create the vertical vibration of the vehicle model and the optimizationmodel of vehicle ride comfort. The content of this part of the work: to create fourdegrees of the vertical vibration of the vehicle model according to the actual structureof the vehicle, and set optimization goals, constraints and the optimization variablesaccording to different road conditions and driving conditions, on this basis, toestablish vehicle ride comfort optimization model.Secondly, it is to establish the equivalent model for shock absorber structuralparameters, and get the structural parameters of the shock absorber by the use ofgenetic optimization algorithm. The part of the core work is to establish accurateequivalent model for the shock absorber structural parameters based on theknowledge of fluid dynamics and hydraulic software AMESim. The model must not only be able to express the influence of structural parameters on the externalcharacteristics of displacement-sensitive shock absorber, but also requires the modelnot be too complicated, otherwise it will affect the efficiency and accuracy ofparameter identification. In addition, the set of constraints and the range ofoptimization variables is a key point when doing parameter identification. In the set ofconstraints we should consider the principle of compensation of the existing level ofprocessing technology and the spare travel of damper. In accordance with the designstandards of shock absorber, we trial displacement-sensitive shock absorber samplebased on the recognition result, and do shock absorber dynamometer performance testand speed characteristic test on the damper test bench, and to validate the feasibilityand effectiveness of the method we use to determine the shock absorber structuralparameters in this article. The last part of this paper we also set the research resultsinto the vehicle vibration model, and do simulation analysis of vehicle dynamics.