Analysis and optimization of vehicle handling stability with considering front and rear suspension hard point coordinates

Abstract

For the front double wishbone suspension, starting from the space analytic geometry, a method of describing the movement law of the its is proposed and kinematic analysis is performed, and then the expressions of front wheel alignment parameters are derived by the vector method. Based on the theory of space coordinate transformation, a method of analyzing the kinematics of the five-link suspension is proposed, and the toe angle and camber angle of the rear wheels are derived. The virtual kingpin of the rear suspension is approximated by the instant screw axis method to obtain the expressions of the kingpin alignment parameters. The sensitivity analysis of the impact of the hard point coordinates on the suspension performance indicators is obtained, and the hard point coordinates that are most sensitive to the front and rear suspension performance indicators are obtained. And this is used as the analysis object to explore the influence of the hard point coordinate changes on the wheel alignment parameters. The frequency response index of the vehicle is derived from the vehicle dynamics model, and the change law of the frequency response index of the vehicle in the low and high frequencies is obtained based on swept-sine input simulation. Finally, the sensitivity analysis of the vehicle handling stability is carried out on the hard point coordinates, and the more sensitive hard point coordinates are selected as the optimization variables. The vehicle frequency characteristic index is used as the optimization target, and the NSGA-II algorithm is used for multi-objective optimization. After optimization, the result shows that the handing stability of the vehicle in the low frequency range has been improved.