Hard point parameter optimization of a wheel-hubdriven electric vehicle suspension based on a three-step screening method

In order to solve the adverse effect on wheel-hubdriven electric vehicle ride comfort caused by the introduction of hub motor, a three-step screening method is proposed to match and optimize the hard point parameters of vehicle suspension. First, a multibody dynamic model of the prototype vehicle suspension was established based on a multibody dynamic method, and the analytical formulas of the electromagnetic force of the motor were given. Based on the specific conditions of the vehicle and the motor, a dynamics analysis of the suspension was carried out to investigate the effect of the fluctuation of the electromagnetic force of the hub motor on the wheel alignment parameters. Second, the calculation model of the suspension dynamics response was established according to the experiment designed by the Latin hypercube sampling method, and a sensitivity analysis of the suspension hard point coordinate was carried out to obtain the sensitive hard point parameters. Finally, the linear weighted synthetic optimization model of the front wheel alignment parameters of the wheel-hubdriven electric vehicle was elaborated using a multi-objective optimization method, and the multi-objective function was converted into a single objective evaluation function to carry out better suspension hard point parameter optimization. The results show that by optimizing the suspension hard point parameter, the wheel alignment parameters can be controlled within a reasonable range. This optimization ensures that the variation rate of the front wheel alignment parameters of the wheel-hubdriven electric vehicle meets the vehicle design requirements, thus eliminating the adverse impact on vehicle ride comfort caused by the introduction of the hub motor. This paper also illustrates that the three-step screening method is an efficient method of parameter matching, which can satisfactorily solve the problem of engineering applications. The three-step screening method can teach assistant engineer how to use this method to conveniently carry out the design of vehicle suspension, simplify the cumbersome design process, save time, and improve work efficiency and design quality.