Suspension K&C Characteristic Test Rig Design And Analysis On Handling And Stability

Vehicle suspension Kinematics and Compliances characteristic as a very important assembly part 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 no doubt about that 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. It has been one of the important problem on vehicle research field that how to design the automotive handling and stability and how to get better automotive active security. Analysis on vehicle suspension K&C will supply valuable help and basis for design. So Research on suspension K&C has been being one of the focuses of automotive dynamics field.On the other hand, automotive digital develop technology in which a lot of work is finished based on computer dynamic simulation technology has been the most important progress of vehicle design field in the modern world since the middle of 20th century. Suspension K&C parameter which is got by test research will fit the computer model in the process of vehicle design. Furthermore, suspension K&C characteristic will affect steering and breaking system trait. So K&C will play a so important part in vehicle chassis develop platform.The dissertation pays more attention to the impact to vehicle handling and stability, especially to steering performance (understeering) by suspension K&C characteristic. Based on the abroad achievements in this field, the following issues are discussed: developing JLU-I Suspension K&C Characteristic Parameter Test Rig and make a lot of vehicle experiment research and performance theory analysis. The main part of this paper is organized as follows:Firstly, the main research content, achievement and development of vehicle suspension K&C characteristic are introduced. The necessary of developing suspension K&C characteristic parameter test rig and the important part played by K&C research in vehicle chassis development platform.Secondly, JLU-I Suspension K&C Characteristic Parameter Test Rig is built, the general functional design and disposing design of which is introduce ed. 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.Thirdly, lots of measuring experiments on car suspension K&C characteristic parameter is finished based on JLU-I Suspension K&C Characteristic Parameter Test Rig. The testing criterion and coordinate about this parameter measuring platform is established. Six kinds of standard testing projects and about forty testing traits are explained. Moreover, two different suits of measuring suspension K&C characteristic parameters based on the same car supplied by JLU-I Test Rig and Lotus are contrasted. The measuring capability of JLU-I has been proved by analyzing the data. The testing data about two kinds of cars are deal with and the K&C trait graphs have been gotten. At the same time, some design suggestions about JLU-I are advanced for the second development.Fourthly, a mass of typical car suspension K&C characteristic parameter graphs are analyzed and compared. The writer studied the influence to vehicle handling and stability, especially to the understeering by suspension K&C parameter in details. In this part, the Kinematics and Compliances traits of toe angle, camber angle, lateral disp-hub-centre and caster are studied and analyzed seriatim. At the same time, the vehicle straight locomotion, stability, returnability , anti-caster is also research. The compliance proportions on every parameter has been given. One computer simulation vehicle parameter model based on the measuring suspension K&C data is built used of CarSim. Writer make lots of computer dynamic simulation experiments on steering handling according to GB of china and find not every K&C factor affect steering trait obviously. The most important factor is toe angle changing as the wheel is under lateral force infliction.Finally, a rank table on every suspension K&C parameter's affective extent to vehicle steering trait is given. And a scientific Statistic experiment design method is advanced for following research.