Design, Construction, Test, Data Processing And Analysis Of Automobile Brake Bench

Automobile brake system is an important component to the safety and the NVH characteristic of automobile,the automotive brake bench is significant to study and improve the brake friction characteristics,improve the performance of automobile brake system and suppress the brake vibration.Based on a certain A00 class mini car,this paper designs and builds a single-end inertial vehicle brake test bench with floating clamp disc brakes.The vibration noise test is carried out on the test bench,and the test data is processed and analyzed.First of all,essential parameters of brake test bench is calculated in design progress,such as the moment of inertia,rotational speed,motor power,braking torque and inertial flywheel structure size,besides the strength of flywheel drive shaft and the inertia is checked.Secondly,according to the test parameters of the test bench,the matching of the test equipment of the motor and the coupling is carried out,and the automobile brake platform is built and installed and debugged.Besides,the hardware and software of bench control system is designed and debugged at the same time.The bench control part of hardware and software system is composed by PC,control cabinet for data acquisition,various sensors and other hardware equipments.The real-time measurement of the test bench speed,system torque and braking pressure and the real-time control of the test bench speed are realized by the automatic control system based on the KingView software and the lower computer PLC.The ladder program is wrote into PLC,which is complied and debugged by GX Developer software,the convenient operation monitoring interface is designed by KingView software.Thirdly,the braking force of the disc brake during braking is analyzed,friction coefficient model of power function product of disc brake and the dynamic model of the single degree of freedom wheel are established by Simulink simulation software,a variety of braking tests are conducted in the automobile braking bench,friction coefficient model is validated,which is fitted well,that is the disc brake friction model can simulate the dynamic friction characteristics of friction stage of disc brake well.And then,the theory and engineering valuable of constant coherence function,multiple coherence function and partial coherence function are introduced,the calculation process of the partial coherence function and the Matlab program for the subject are also prepared.Through a simulation of four input,single output system model,the algorithm isverified,which can be used to identify the sources of noise and vibration of disc brake in this paper.Finally,the vibration and noise test is conducted in the self-made brake test bench,using the method of constant coherence and partial coherence,the characteristics of the acoustic signal produced by the disc brake are analyzed and the noise source is identified,the contribution of each direction of the vibration signal to the noise at each main coherent frequency is determined,which provides a reference for the further study on the vibration and noise of disc brakes.