The Software Development Of Integrated Electrical Parking Brake

The automobile electronic parking system is an important unit for realizing the function of temporary safe parking and long-term parking after flameout.At present,there are two types of electronic parking systems commonly used in passenger cars:1.An electronic parking system with an independent control unit;2.An integrated electronic parking control(EPBi)system.With the continuous and in-depth development of automobile intelligence,integrated electronic parking has become the trend of future development.At present,EPBi has been widely used,and its characteristic is to integrate the parking control software(PBC)into the ESC software,and share the hardware controller with the ESC to control the electronic caliper to realize the parking brake of the vehicleWith the continuous deepening of chassis integrated control technology,PBC software has gradually evolved into an independent and universal software module,which can be integrated into different controller products to achieve vehicle parking brake control.The PBC technology was jointly proposed by European and American suppliers and OEMs,and jointly formulated a unified technical standard to ensure that the IPB system can be matched between products from different suppliers.At present,Volkswagen,GM,PSA and other OEMs have their own complete EPBi system design solutions;the PBC systems of ZF,Bosch,Continental,and Panbo have formed mature and stable technical solutions and products,and occupy passenger cars.The vast majority of the market.Because the development,testing,integration and calibration technology of PBC software has been in the hands of the above-mentioned foreign suppliers for a long time.Domestic OEMs need tens of millions of development costs to use its technology,which increases the cost of manufacturing vehicles.In order to achieve independent control of this technology,we must develop independently,accumulate research and development experience,and establish independent research and development capabilities for electronic parking systems.This subject relies on the integrated ESC software and hardware and integrated environment to develop PBC software.The main research content includes software interface definition,function definition,model building,test analysis.In order to make the PBC software have a higher generalization,the interface will mainly refer to the recommended interface in VDA＿305-100.The function definition will be mainly based on the study of the electronic parking system of Dongfeng G35 models,determine the function definition,and refine it to the signal level to establish the foundation for the model building.Then build a control model based on the function definition and test the model.Among them,the functional modules include static clamping,parking release,dynamic parking,drum mode,rolling re-clamping,intelligent parking,maintenance release,and hydraulic auxiliary parking seven modules.In order to ensure the control accuracy of the PBC software,we will introduce the working principle of the electronic caliper.The development process is carried out in accordance with the V process model.Through the analysis of user usage scenarios and comparative analysis of competing products,determine the subject research content and determine the function definition;decompose the function definition,determine the function module,and refine the function definition to the signal level;build a control model according to the definition and generate C code;test control Model,and compile and integrate the software.This topic is to build a control model through Simulink to realize parking and parking release functions.And adopt the hierarchical parking strategy to realize the dynamic parking function.In order to enable the vehicle offline detection to detect the failure of the parking system,a multi-stage drum mode is designed.In order to ensure normal assembly and replacement of friction plates,a control strategy for maintenance release is designed.In the test link,to ensure the adequacy of the test,a normal state test and a failure test were carried out,The test results meet the design requirements.