Research And Development Of Vehicle Control Unit With Model-Based-Design Technology

In recent years,the demand for high quality software of embedded system in vehicle is increasing.The importance of the reusability,reliability and development efficiency of software is growing.The traditional way to develop the vehicle software has hardly met this kind of request due to its characteristic of handwriting coding,heavy workload and low efficiency.To fix the issue of the traditional develop method,this thesis researched and adopted the model-based-design(MBD)method and developed a vehicle control unit(VCU)for a pure electric vehicle with this approach.This thesis begins with the introduction to the process of model-based-design,compares this process with the traditional method,than defines the hardware and software requirement of VCU by analyzing the control structure of the target electric vehicle.The microcontroller’s model can be determined according to the hardware requirement.With the defined software requirement,the process of MBD is implemented to develop the VCU.The first part of work described in this thesis is the development of basic software for target microcontroller that is adopted in VCU,this part explains how to build the customized system target environment by programming the system target file,the code generation control file and other assistance file to control the code generating process.Another work in this part is to build the customized block by programming the Sfunction and target language complier file according to the vehicle requirement.To satisfy the need of monitoring the running state of the VCU and downloading the software into VCU,and CCP protocol drive model for target MCU is also developed.The second section is the design and the modelling of the application software for the VCU.The running status of electric vehicle is firstly analyzed for designing of state machine of the application software.The state machine is divided into 6 part.With signals that VCU collects,the transition trigger is also designed.To assure the steady of accelerate pedal signal sampling while the vehicle is travelling,an algorithm filter is designed and modelled in this thesis.Also,to ensure the good vehicle dynamic performance,a strategy based on fuzzy logic is developed.In addition,the failure manage system is developed by analyzing the potential failure that may happened in target electric vehicle.The third section depicts the code generation from the model of the basic software and application software and the analysis on volume and efficiency of the codes generated.To comply with MBD process,the software is validated and verified with methods such as model-in-the-loop,software-in-the-loop and processor-in-the-loop,to prove its correctness.In general,this thesis researched and studied the MBD developing method and developed a VCU with some specific requirement by performing the MBD.Therefore,this thesis own the practical meaning of the development of vehicle software.