Suspension K&C Characteristic Sensitivity Analysis To Automotive Handling

Vehicle chassis platform design is mostly the design of suspension, suspension is the soul of the chassis, so K&C characteristics of automotive suspension research and analysis is particularly important, and it is critical to vehicle handling and stability, and the role of guiding significance to improve their quality. Vehicle suspension Kinematics and Compliances characteristic is offered to describe the wheels'kinetic state when the springs is pressed in the process of running or the car body is roll when the car is turning.There is some important complete vehicle performance will be affected by suspension K&C characteristic, such as straight locomotion, turn-running steering locomotion, stability, returnability, anti-caster and NVH. The sensitivity analysis of suspension K&C Characteristic to Automotive Handling is of utmost importance to the improvement and modification of vehicle chassis.The dissertation focus on the theme of sensitivity analysis of suspension K&C characteristic to Automotive Handling.Based on JLU-I suspension K&C characteristic parameter test rig, developed JLU-II suspension K&C characteristic parameter test rig, and measuring experiments on suspension K&C characteristic parameter is finished , new test results are used to improve and perfect vehicle model, model verification results show that the new model are more accurate, at last we get the sensitivity of suspension K&C Characteristic to Automotive Handling by the experimental simulation of Automotive Handling. The dissertation is divided into five chapters.Chapter one, Introduction.The main research content, achievement and development of vehicle suspension K&C characteristic are introduced.The necessity of developing suspension K&C characteristic parameter test rig and the important part played by K&C research in vehicle chassis development platform.Chapter two, JLU-II suspension K&C characteristic parameter Test Rig build and research. JLU-II Suspension K&C Characteristic Parameter Test Rig is built, the general functional design and disposing design of which is introduced. The function theory, configuration design, measuring element and measuring accuracy of the wheel-suspension load system, car body fixed system, wheels'kinetic parameter measuring system, data collection system and software controlling system is discussed particularly.At last,the test projects and technical indicators are summarized.Chapter three, based on JLU-II Suspension K&C Characteristic Parameter Test Rig,the K characteristic of suspension wheel jump kinematics, the K characteristic of suspension roll kinematics, the C characteristic of suspension longitudinal flexibility, the C characteristic of suspension lateral flexibility and the reverse stiffness of steering system are measured.In parametric modeling and simulation software ,we improve the model of a certain vehicle with datas measured by JLU-II suspension K & C test rig, and on the basis of national standards,the steady steering characteristics ,steady roll characteristics and properties of vehicle transient steering, as well as to the central area steering characteristics are simulated, and the test results and simulation results were compared to verify the model accuracy.Chapter four is the core of the dissertation, there is the sensitivity analysis of the suspension K&C characteristics to Automotive Handling. Firstly summed up a certain car K&C characteristics, according to simulation modeling features and analysis capabilities of Carsim software, pick up a part of K&C characteristics, statistic performance value of this part K&C characteristics, and then combining Automotive Handling test simulation including the open-loop simulation and closed-loop simulation, which open-loop simulation includes steady rotation test, the steering angle pulse test, the steering angle step test, and the closed-loop simulation is double lane change test, analyse impact extent of this part K&C characteristics to Automotive Handling, including the influence of K&C characteristics to understeering in steady-state rotary test, K&C characteristics to peak frequency in steering angle pulse test, K&C characteristics to the reaction time in steering angle step test, the closed-loop simulation use the closed-loop system evaluation, then the evaluation indicators were calculated value, and quantitative analysis, finally sum up sensitivity of suspension K&C characteristic to Automotive Handling respectly.The final chapter is the conclusion part, the comprehensive summary and conclusion analysis are done in the dissertation.