Simulation And Experimental Study On Modeling Load Force Of Chassis Dynamometer

With the development of sorts of technologies of automobiles,the demands for automotive functions is also increasing.Under the circumstance of low-carbon living,energy conservation and emission reduction,the dynamic performance,economical efficiency and exhaust emission of vehicles are gradually becoming the focus of people.In recent years,due to the revision of standards of vehicle detection,the accuracy of detection is also improving and the request to vehicle performances is stricter.As the essential equipment for detection,Chassis dynamometer must simulate the road driving resistance of automobile which is the primary condition to guarantee the accuracy of detection results.This paper is mainly about the research of the real-time simulation of road driving resistance of chassis dynamometer.To determine the road driving resistance and the rolling resistance of chassis dynamometer,this paper primarily conducts the force analysis of the process of driving and the process of detection.In order to get the formula calculating of the target value of loading force of the eddy current dynamometer,this paper uses the method of sliding to determine the inner resistance of chassis dynamometer;To determine the relational expression of torque,rotate speed and electric current of eddy current dynamometer,this paper deduces the theoretical calculation of loading force of the eddy current dynamometer bases on the method of disc and uses the linear regression method to analyze the experimental data and employs the least square method to fit the structural parameter of the eddy current dynamometer.Then,establish the entity models of different parts in the software Solidworks bases on the eddy current dynamometer of DCG-10 D,and to set the properties of them in the View modules of the software ADAMS.By adding the restraints and driving forces of different parts,the paper gets the dynamical models of the chassis dynamometer.To analyze the dynamic properties of the eddy current dynamometer,this paper sets the import and output of the dynamical models of the chassis dynamometer,defines the state variables and parameterizes those variables.In addition,this paper constructs the PID control models of the dynamometer in the Tool Box of the software Matlab/Simulink,sets the interactive conditions of the data getting from the co-simulation between controller and dynamical models and sets up the co-simulation control system of multiple-input parameters related to the vehicle parameters and road parametes.By setting the condition of the simulation,the steady-state operating conditions are simulated and the feasibilities as well as the control effects are determined.In the last part of the paper,construct the equivalent sliding models of the bench,to quantify the sliding models of bench and simulate the road sliding experiment precisely,the correction factors of inertia are introduced to revise the equivalent models.To verify the loading models of the eddy current chassis dynamometer and the control system can simulate the road driving resistance of different operating condition,the road sliding experiments are designed,the experimental results are recorded,the simulation conditions that are similar to the road experiments are set,the co-simulation platforms that can conduct sliding are built and the data from simulation and field experiment are contrasted.According to the dynamic performance,economical efficiency and exhaust emission of vehicles claimed in the national standard,if the detection errors are compensated,then the detection accuracy can be improved;if the road sliding is replaced by the bench sliding,then the cost of road experiment can be reduced.