Hardware Development Of Electronic Control Platform For Shift-by-wire System Based On Functional Safety Standard

The mechanical hydraulic automatic transmission transmits the signal to the gearbox through the mechanical cable,wrong operations of the driver in the process of driving will cause serious damages to the transmission,even make casualties.The shift-by-wire system can make a logical judgment of the driver’s operation before action.The shift request that conforms the current vehicle driving state can be executed by the shift-by-wire actuator,so as to protect the people and vehicle.Shift-by-wire system improves the comfort and reliability of shifting process,but also brings safety problems faced by electrical design,such as component failure,sensor failure and other factors which could lead to wrong shifting and endanger personal safety.Therefore,designers of shift-by-wire system should keep the risk within acceptable level.To this end,the International Organization for Standardization(ISO)published the ISO26262 standard.This standard mainly puts forward a concept of automobile life safety cycle,provides an analysis method to determine automobile safety integrity level,defines requirements to avoid unreasonable residual risks based on safety integrity level,and provides effective measures to ensure adequate safety level.In this paper,based on the functional safety standard,the hardware development of electronic control platform for shift-by-wire system controller is completed,which is intended to be the basis of further research on shift-by-wire system and functional safety standard.First of all,according to the third part of ISO 26262 standard,the safety integrity level and safety objectives of hazard events were obtained through the definition and analysis of related items.According to the system functions,the preliminary system architecture was proposed,and the functional safety requirements were assigned to the elements in the system architecture.Secondly,FMEA analysis and FTA qualitative analysis on system level of shift-by-wire system were carried out in line with the 4th part of ISO26262 standard,the fault-tolerant time interval was determined by experiment,and the system architecture was improved.Then,based on the system architecture,this paper determined the hardware scheme,and completed chip selection and circuit design of each module on account of the specifications of safety mechanism,the requirements of system function and the fifth part of ISO26262 standard.Then,this paper completed the evaluation of the hardware architectural metrics and the calculation of random hardware failures rate of the system according to the fifth part of ISO26262 standard and IEC62380 standard,which proved that the system satisfies the functional safety requirements in the design phase.Finally,the basic software and application software based on AUTOSAR architecture,which implemented the basic I/O functions,were completed,and the basic input signals and output signals of the system were verified to be accurate and real-time,which proves that the hardware design of the shift-by-wire system meets the functional requirements and lays a foundation for further research.