| Automatic transmission of powertrain is one important aspect of vehicle electronics, and is also the trend of the vehicle technology. Automatic transmission greatly improves vehicle performance, efficiency and greatly alleviates the driver's working intensity. The goal of this thesis is to study and develop some essential control technologies and simulation system of automatic transmission.Firstly, control technology of automatic transmission gear shifting and the development process are introduced and concluded by the numbers based on a lot of literature. Moreover, the main researching contents of the thesis are outlined. Structure and work principle are analyzed, and the existing control technologies of automatic transmission are summarized. Especially, the existing control technologies of shift quality are investigated and concluded in details.Secondly, based on the analysis and investigation of characteristics of subsystems of automatic transmission, the thesis develops the dynamic models of 1st-4th gear upshifting using the method of free-body diagram with the help of a lot of models. And then, the details of shift process are analyzed.Thirdly, this thesis develops a 1st-4th gear upshifting dynamics simulation system of automatic transmission based on Matlab/Simulink. Several simulation technology problems due to modeling methodology are discussed and solved mainly. Based on the analysis of simulation results and the simplified realization of the simulation system, the consistency of the simulation system and dynamic models is verified. Using this system could easily acquire simplified conclusion for the process of gear shifting, and provides powerful tool for the control of the shift quality.Finally, closed-loop shift control algorithms for clutch's hydraulic pressure are developed based on these linearized models and implemented in the simulation system. A elementary research on shift quality control is presented at the end of the thesis. |
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