Research On Modeling And Optimal Design Of Double Wishbone Front Suspension System For Baja Racing Car

Launched in 2015,Baja SAE China has successfully held seven races until 2020.Over the past five years,the number of participating teams has increased year by year,and it has reached hundreds each year.In this paper,the deformation of steering knuckle and the crack of lower control arm of Baja racing car are taken as the research objects.The simulation model of the front suspension is established.The static stress analysis and optimal design of the key parts under limited conditions are conducted.The kinematical simulation analysis of front suspension is made.The optimization of the main positioning parameters and the kinematical simulation analysis and evaluation of the vehicle handling stability after the optimization of front suspension are carried out.The main research work of this paper includes the following three aspects:1.In view of the deformation of the front suspension knuckle and the crack of the lower control arm in the test of Baja racing car,the static stress analysis and modal analysis of the knuckle and the lower control arm are carried out under limited conditions.Aiming at the problems of excessive degree of understeer and vehicle roll angle in the test,the kinematical simulation of the front suspension is conducted.And the wheel alignment parameters and roll characteristics are analyzed.2.The structure and material optimization of the front suspension knuckle and lower control arm of the sample vehicle are carried out respectively.The static stress analysis and modal analysis of the optimized knuckle and the lower control arm are carried out under limited conditions.The results show that the optimized method is correct.ADAMS / Insight software is used to set parameter variables and optimized objectives.Quadratic model is selected to fit the relationship between parameters and optimized objectives,and the sensitivity relationship between parameter variables and optimized objectives is judged.On the premise of ensuring the minimum change,the response surface methodology is used to optimize the positioning parameters and roll characteristics of the front suspension of Baja racing car.After the optimization,the performance of the front suspension of the car is improved,which verifies the effectiveness of the optimization of the front wheel alignment parameters and roll characteristics.3.Finally,the handling stability of the optimized front suspension simulation model is analyzed by slalom test,steering Wheel Angle step test and steady state cornering test.The test results show that the maximum steering wheel angle is 23.15°,11.85°less than that before optimization.After the optimization,the maximum yaw angular velocity is 34.9 °/ s.It improves by 12.3% compared with that before optimization.The test evaluation scores were increased by 11.43 points,22 points and 10.79 points respectively.This optimization improved the transient response capability and rapid cornering capability of the car.The research results of this paper not only provide guidance for the design,manufacture and debugging of the front suspension of Baja racing car,but also provide some references for the design and analysis of the double wishbone suspension in the future.