The Optimal Design Of The Torsion Bar And The Front Double Wishbone Suspension For A School Bus

As one of the main factors affecting the safety of the car, handling stability hasbecome one of the most important performance indicators. The wheel alignmentparameters which are determined by the suspension system have direct influence onthe handling performance of vehicle. Therefore, the optimization of suspensionsystem has important theoretical value and practical significance.This topic takes a double wishbone suspension with torsion bar for a school busas the research object, optimize the suspension structure and steering system designthrough theoretical analysis and considering the exiting problems, such as the poordriving stability, the severe wear of the front wheel, the bad steering return ability, etc.Then design a new torsion bar spring according to the theory of optimization design.The paper’s main content includes:First of all, analyze the influence of wheel alignment parameters on tire wear,provide theoretical basis for optimization design of the back.Secondly, the frequency of the suspension does not meet the requirements ofcomfort which is calculated according to the parameters provided by enterprise andthe3D model of front suspension. Redesign the size of the torsion bar and establishthe finite element model to validate the rationality of the torsion bar spring size afteroptimization on the maximum torque conditions.Thirdly, taking the double wishbone with a torsion bar front suspension in theschool bus type as the research object, the virtual simulation of front suspension andsteering system model is set up through the parameters which are provided byenterprise and the3D model of front suspension, and then the kinematics simulationanalysis and the steering ackerman error are carried on.Then, the sensitivity analysis of key hard point coordinates from the frontsuspension was conducted with by using the Insight module. Selecting the largersensitivity parameters as design variables, the response surface approximate modelwhich can simulate the relationship between design variables and the maximalvariation of toe angle, camber, wheel track and the ackerman error are established.Then the approximate models are optimized by the improved genetic algorithm.Finally, validate the results of optimized analysis in ADAMS, it is concluded thatafter optimization the change of the toe angle is reduced by67%, and the change of camber angle and wheel track are within the scope of the ideal. The ackerman errorhas been reduced significantly, which improves the performance of suspension,reduces the tire wear, and the stability of vehicle is improved.The research content of the paper uses theoretical and empirical knowledge tosolve practical problems, combine with production practice closely, and put forward aclear solution for analysis of the front suspension in the engineering. It has theimportant practical significance to the analysis and designs the front suspension.