Research On The Control System Of Two-speed Automatic Transmission For Electric Vehicle

The endurance capacity of electric vehicles is still restricting the development of electric vehicles,Nowadys,there are mainly two approaches to improve the endurance capacity of electric vehicles,increasing the capacity of the battery and improve the efficiency of the drive motor.Multi gear transmission can achieve the climbing performance as well as maximum speed performance,but by optimizing the fixed gear is difficult to get these two performance.Therefore,the automatic transmission can not only make the drive motor often work in high efficiency range,but also can improve the dynamic performance.In this paper,the control system of two automatic transmission is designed,The main contents are as follows:1)According to the design requirements,determine the power of the drive motor,and analyze the characteristics of the drive motor.2)Drive motor has excellent speed control performance,therefore,the powertrain can be designed without clutch;considering the constant torque performance of drive motor,the two gear of automatic transmission can meet requirements,and according to the design requirements to determine the transmission ratio of each gear.Through reforming the powertrain of the internal combustion engine vehicle,we get a experiment platform for further study.3)In order to improve the safety and the dynamic performance of electric vehicle in climbing condition,this paper designs the ramp recognition module of electric vehicle with the multi signal fusion technology.4)Through the analysis of characteristics of electric vehicle driving motor,make the economic shift schedule,and amend this economic shift schedule with the ramp and driver intention;By analyzing the dynamic characteristics of the two gear automatic transmission,design the self-regulation and recovery strategy of torque,which meet the two gear automatic transmission features.Through the analysis of existing problems in ramp start of electric vehicle,and combining with the ramp angle,we make the ramp start control strategy of electric vehicle.5)Through analysis of the input and output signals of the automatic transmission control unit TCU,designes the TCU hardware circuit.Combining with these control strategies,designes the TCU control system software.6)Install the automatic transmission control unit TCU into th test car,implement ramp recognition experiment,shift experiment and vehicle performance experiment.The experimentresults show that the TCU can execute the shift action,and the performance of the test vehicle meets the design requirements.In this paper,the design of automatic transmission control system of electric vehicle has important practical significance,and provides a technical platform for further improvement and optimization.