Simulation And Experimental Research On Automotive Braking Unbalance Rate Detection Error Based On Bench

In recent years,the automobile market has become increasingly exuberant and the automobile safety performance detection therefore turns out to be more and more important,among which the braking performance detection is one of the most significant items.Besides,the automobile braking unbalance rate is a vital index to measure whether the braking performance is qualified or not.With the revision of national standard,the accuracy requirement of automobile braking performance detection is enhanced gradually.Among all the braking performance detection methods,roller opposite forces type brake tester is widely used at home and abroad.Thus,in this paper,the research about braking unbalance rate detection error is carried out based on simulation and real vehicle experiment,taking roller opposite forces type brake tester as the bench.By consulting relevant materials to investigate the research status of automobile braking performance detection,according to the lack of research on automobile braking unbalance rate detection,determine the analysis of braking unbalance rate detection error as the main research content of this paper.Through the force analysis of the tested wheel and the braking force's transferring process in the bench,it comes out that different vehicle braking force and the rotational inertia of the bench will have effect on the braking unbalance rate detection error.Based on the above studies,taking Chengbao FZ-13 C type roller opposite forces type brake tester as the prototype,the 3d model of each part is constructed by SolidWorks in turn,and the bench model is obtained by bottom-up assembly method.With the vehicle simplified and assumed as necessary,taking Audi brand vehicle as the prototype,the model of each subsystem of the vehicle is established by ADAMS/Car module.The assembly of the vehicle model is realized by setting the communicator connection between each subsystem and the assembly of the vehicle-bench model is completed in the ADAMS/View module.Set simulation parameters for the vehicle-bench model.In order to simulate the rotational inertia of the motor and reducer,a pair of inertial flywheels is introduced on the basis of the vehicle-bench model.With the simulation experiment conditions set,divided by wheel loads,three groups of the simulation experiment is designed.During the whole simulation analysis process,the mass of the inertial flywheel is changed and a Python program is designed to calculate the braking unbalance rate and its detection errors in order to output the finalsimulation experiment results,the results show that the decrease of vehicle braking force and the increase of rotational inertia of the bench will lead to the increase of braking unbalance rate detection error.At the same time,the dynamic response characteristic of the system is analyzed,which reveals that the bigger the inertial mass of the flywheel,the longer the system dynamic response time.Design the general scheme of real vehicle experiment,use the automobile brake performance detection system and the six axis wheel force transducer to output the corresponding measurement results and design the data processing program of the six axis wheel force transducer based on Python.By calculating the braking unbalance rate detection error of the three different types of vehicle,it is verified that braking unbalance rate detection error will increase with the decrease of vehicle braking force.Furthermore,by comparing the result of the simulation experiment with the real vehicle experiment as well as calculating the error of the vehicle-bench simulation model,the results turn out that the gaps between the results of the simulation and the real vehicle experiment are small,and the simulation model can well simulate the braking performance detection performed on the bench,which provides the data and theoretical basis for the future detection of the vehicle braking unbalance rate as well as the revision of its evaluation criteria and is of great significance to improve the detection accuracy of roller opposite forces type brake tester.