Analysis Of Suspension Characteristic And Experimental Optimization Based On K&C Test

From the perspective of design improvement of a sample car, this thesis investigates the evaluatioin of suspension K&C characteristic, establishes ex-Mcperson suspension model, simulates and analyzes suspension K&C characteristics before and after adjustment, and optimizes its shortcomings. This paper reads as follows:1.the evaluation parameters and methods of suspension K&C characteristicsThis thesis expatiates the evaluation parameters and mothods of suspension K&C characteristics. The former inculdes 8 aspect: camber angle, toe angle, kingpin inclination angle, inclination moment arm ,caster angle, caster moment ,wheel track and axle track, the parameters affecting the lateral and longitudinal stability of vehicle. This thesis expounds the definition of these evaluation parameters and analyzes its influence to vehicle handling stability. And it sets forth test methods of evaluating suspension K&C characteristics, including parallel wheel travel, opposite wheel travel, single wheel travel, roll and vertical force, static load and steering test.2. the suspension K&C testThis thesis introduces structural principle, clamping, test methods and test contents of suspension K&C characteristic test rig. The relevant parameters and partial ex-Mcpherson suspension K&C characteristic curve are measured by using suspension K&C test rig. This test consists of partial suspension kinematics characteristic in parallel and opposite wheel travel and patial compliance characteristics when loading longitudinal force, lateral force and aligning torque, and measure wheel alignment and other suspension modeling parameters.3. the build of suspension system virtual prototype modelBased on the basic test parameters and relevant modeling data of ex-McPherson suspension of the sample car, the virtual prototype model of this suspension is built by making use of ADAMS/CAR module. It works out hard point space coordinates of the suspension, analyzes topology of McPherson suspension framework, builds the virtual prototype model of suspension and steering system, and assemblies suspension system, steering system and suspension virtual test rig to get the virtual prototype model with characteristics of stimulated and analyzed suspension K&C. Through adjustments of model parameters, the characteristics of K&C before and after adjustment can be analyzed, which lays a foundation for the analysis of the model in the next chapter.4. Suspension K & C Properties Simulation Analysis ModelAccording to the requirements of the relevant design, some of the model parameters have been adjusted, on the basis of which, K&C characteristic simulation before and after the adjustment is done. K&C characteristic simulation includes parallel wheel travel test and static loading test. This thesis analyzes the K&C characteristic before and after the adjustment of the suspension model. They are kinematic characteristics of camber angle, toe angle and wheel track caused by wheel travel, compliance characteristics of ooe angle, wheel track and camber angle, roll and roll rate caused by lateral force, compliance characteristics of Camber angle, toe angle, wheel track and anti drive caused by vertical force, compliance characteristics of Roll camber coefficient, roll steer coefficient and steer angle caused by lateral and vertical force. The results show that: after adjustment, the majority of suspension K&C characteristic is satisfied, but the changes of toe angle, camber angle and wheel track are still large. 5. The Optimization Analysis of Test Suspension SystemFocusing on the problems that toe angle, camber angle and wheel track alters evidently in the simulation results in the fifth chapter, the thesis optimizes some coordinates of the suspension hard-points with ADAMS/Insight. Then it pointes out that the three coordinates of hard-points influence on suspension kinematics characteristics such as toe angle, camber angle and other parameters, and confirmes a better coordinate location. According to the optimized results, the thesis adjustes the suspension model and performes the simulations, and then makes a comparitive analysis in kinematics characteristics before and after the optimized suspension through parallel wheel travel test. The results show that the performance of the optimized suspension is evidently improved.