Sensitivity Analyse And Optimize Of Suspension Kinematics & Elastokinematics On A Off-road Vehicle

In the beginning,we analyse the characteristic of kinematics and Elastokinematics of Suspension in the article.Then we have talked about the design of experiments.In the automatic dynamic analysis of mechanical system(Adams), vehicle model has been created,we use the optimize sofeware ADAMS/Insight to analyse the double fishbone suspension.we have calculated the sensitivity of the K&C characteristic. Based on this,we can modify the most sensitive factors to optimize the suspension.The kinematics sensitivity analyse is to find out the mostsensitive coordinate of the hardpoints that affect the suspension angles and wheelbase/wheel track.We do the experiments in the parallel wheel travel in Adams/Car.In the experiments,we prescribe the travel of wheels from-100mm to 100mm.In the target functions, the absolute of camber is aimed to the maxim,and the toe angle is aimed to change least.The variation of the hardpoints is given -1mm to 1mm. In ADAMS/Insight,we made design of the experments,then we can get the most six factors that affect the suspension angles and wheelbase/wheel track. If the factors have got,we can change the propriety factor to modify.By the way of validate the sensitivity of the kinematics,we also make the variation from -5mm to 5mm/-10mm to 10mm.In the result,the infection of the factors minish in proportion.We also say that the result is only come into existence in the given suspension.The optimizing of the suspension's kinematics is changing the factors that have been calculated above,and make the aiming functions the best.After analysing the army'suspension,we getthat the camber and the toe angles changed by the wheel travle are not ideality.So we consider the two angles as the function. Pay attention that the suspension is almostly confirmed,so we can only change few factors.After many trials,we get that for the front suspension the hardpiont tierod outer's Z coordinate change from -31.37mm to 19mm,and the hardpiont upper control arm's Z coordinate change from 143.5mm to 163.5mm; For the rear suspension, the hardpiont upper control arm outer's Z coordinate change from 210mm to 150mm,After the optimzing,we also validate the other suspension parameters,aiming that those parameters change not too much.The Elastokinematics sensitivity analyse is to find out the most sensitive stiffness of bushings that affect the suspension angles and wheelbase/wheel track.In the article, the lateral force load increases to 3000 Newton gradually.In Adams/Insight, we made design of the experments,and the stiffness of bushings vary from -10% to 10%,so we can get the most six bushings's stiffness factors that affect the suspension angles and wheelbase/wheel track.The longitude force and the align momentcan get the most chief factors using the method above.The first method that give the most factors about suspension Elastokinematics is fit the given stiffness in the model,and can only change few factors.Now,we introduce another method. Via some propriety suppose,the curves that the suspension parameters under the loads changed by the stiffness of bushings are almostly inverse proportion curves.so we can get the sensitivity table.This method is suitable for the beginning of suspension design.A set of stiffness is given by experience,then the sensitivity table can be calculated.If this set is not suit the suspension,we can use the table to change the stiffness rapidely.In respect that the Elastokinematics characteristic had been improved after the kinematics parameters had been changed.So we have do nothing to the bushing stiffness.The article analyses the army's suspension.Aming at the problems,we modify the suspension parameters,and get the better suspension characteristics.