Research On Model Of Electronic Control Automatic Transmission System

With the development of simulation technology,the effect of model simulation is approaching reality.Using simulation technology to develop and test vehicles has become a feasible technical solution.High-precision,real-time simulation models can achieve high-risk testing under laboratory conditions,reproduce the test environment,and even replace part of the calibration work,greatly shorten the product development cycle,reduce product development risk and test costs.Therefore,the development of the real-time dynamic model has become one of the current international research.The automatic transmission system,a main component for coordinating speed and torque beteween engine and wheels,it is closely related to the vehicle’s power performace,economy,and drivability.At present,real-vehicle automatic transmissions all have transmission control unit which determines the gear position and control based on the driver’s intention,vehicle state,driving environment.However,the current mature commercial dynamics simulation software does not have a controller model,just using a single basic model shift table to determine the gear position,Thus leads to low simulation accuracy and poor adaptability;Meanwhile,lacking of actuator model,the interface is inconsistent with the actual vehicle,and no accurate modeling of the shift process,resulting in the model can’t be connected with the external model or physicals,can’t reflect the the transient phenomenon during shifting.Based on the above analysis,the content of this paper is as follows:1.Based on complete functions,consistent interface and real-time simulation requirements,this paper proposes a TCU functional model of AT automatic transmission.The model has a more complete basic shift mode,can identify changes in external vehicle environment and driving intention,and dynamically correct the shift curve.The model gear position decision takes into account the influence of driving environment and driving intention,so the model simulation accuracy is higher and the model condition is more adaptable;Having the basic lockup mode,making lock decision considering the influence of the braking and shifting status,So the locking decision is more precise;Analysing the reasonable pressure curve control of the shifting clutch under different shifting conditions,so the model can reflects shift transients caused by pressure control;Taking into account the coordination of the torque with EMS during shifting,so the model has the ability to coordinate and communicate with other ECUs.2.In order to make the model accurately express the transient phenomenon during shifting and adapt to the automatic transmission controller interface,this paper proposes a real-time dynamic model of the automatic transmission considering the shift process.The model controls the actuator model by pressure,has a Hydraulic torque converter model with lock-up clutch.For the entire automatic transmission,this model is based on the changes in the degree of freedom of the powertrain during the driving process of the vehicle,and using the concept of “phase” in finite state machine,judging the “phase” by the lockup clutch state and the gear position.Among them,the "sliding and shifting phase" is made to describes the "inertial phase" and "torque phase" in the shifting process,which makes the model have the ability to reflect the steady and transient phenomena,"shift shock" changes in the shift process and negative phenomena such as "power interruption" and "overlap brake" caused by irrational actuator control.3.Integrate the established AT automatic transmission system model into the original ASCL vehicle model for offline simulation.The results show that the simulation accuracy,and the adaptability of working conditions have all improved significantly due to equipped with fully functional TCU function model and dynamic model which considering shifting process.