Design And Research Of The Test Platform For Pure Electric Vehicle Control Unit

As the control core of vehicle control system for pure electric vehicle,vehicle control unit(VCU)plays a key role in vehicle's drive control,brake energy recovery,fault diagnosis and processing.With the continuous improvement of endurance mileage and driving comfort requirements for pure electric vehicles,the complexity of the hardware and software of VCU is also increasing.The current test platform is not only expensive,but also lacks the functional safety test on VCU.So,this thesis designs a platform for functional test and functional safety test on VCU.Firstly,according to the function of VCU and road vehicles functional safety standards,this thesis evaluates the risk of VCU,and calculates the fuctional safety target of VCU.This thesis proposes functional test requirements for the specific functions of VCU.Referring to the road vehicle functional safety standards,this thesis also proposes functional safety test requirements for VCU.Secondly,according to the test requirements for VCU,combined with the existing hardware conditions of the laboratory,this thesis proposes the overall structure of the test platform,and designs hardware.This thesis builds a forward simulation model of pure electric vehicles,including a driver model based on PID control,a drive motor model with a motor thermal model,a battery model based on equivalent circuit model and SOC estimation using the ampere-hour integeration method,and a vehicle dynamics model based on the equations of vehicle driving.Then,this thesis designs the platform self-checking module and the basic test module for VCU to test whether the external interface of the platform and VCU is working properly.This thesis designs the program update module based on UDS protocol,and realizes the online program update to VCU.Based on LabVIEW and Simulink jointly,this thesis develops a function test module for VCU,and achieves the drive control function test as well as fault diagnosis and processing function test on VCU.In this thesis,the functional safety test module to VCU is designed with reference to the road vehicle functional safety standards.Finally,in accordance with the test process,the design of test platform is verified through self-inspection,as well as CAN communication test,interface test,drive control function test,fault diagnosis and processing function test,and functional safety test on VCU.The pure electric vehicle VCU test platform designed in this thesis is economical,practical,highly expandable and flexible.It can realize the functional test and functional safety test on VCU,which is helpful for the improvement of VCU technology level.It also has certain reference value for the design of similar test platforms.