Research On Control System For AMT Electric Shifting

Electronic control automated mechanical transmission(AMT) is a kind of system where electronic control system is equipped on the dry clutch and shafted gear transmission. It takes the advantages of the traditional manual transmission and auto-shift, making it play an very important role in automatic transmission products. The implement of the auto-shift function of AMT in a good shift quality is greatly depended on the performances of shifting control system. Therefore, it is necessary to research the control system of electric shifting in detail. The main contents are as follows:Firstly, the theoretical analysis of shifting process. The shift quality and its influential factors in different stages are analyzed. It is found that the synchronous phase is the key stage of shift quality control in the gearshift process. Based on the manual shift actuator structure form, the self-locking and interlocking resistances of fork shaft were analyzed, and the mathematic expressions about the self-locking resistance and fork shaft axial displacement are brought in. From the working principle of inertia lock-ring single-cone synchronizer, its mathematical model is built. Through force analyze in the synchronous course, the mathematical models of the driving/driven shaft parts in the locking synchronous stage are obtained. According to the allowable value of the friction power, the constraint condition of shift force is defined in synchronous course.Secondly, the research on electric shift test device. Considering the factors such as shifting time, locational control precision and spatial arrangement restricted, the design scheme of test bench is put forward. The choice of the motor types, structures, driven modes and its PWM control methods has been completed. Based on what mentioned above, the motors’ mathematical model was established in shifting process. The structural parameters of actuator are set through building the offline simulation model of test bench and simulating tests by MATLAB/Simulink. And the three-dimensional modeling is completed throught UG, and then the feasibility of the test bench scheme is verified through motorial simulation of the test bench.Thirdly, the research on the electric shift control methods. According to the requirements of automatic shift control system, the system control targets are put forward. The BLDC motor control system and different types of PID control algorithm are tested. On these bases, three kinds of shift motors control methods were selected, and their corresponding offline simulation models were established respectively, and the simulation tests were conducted in the no-load and load conditions. The results show that the selected methods meet with requirements on shift time and positional precision, but they have different control effects and implementation difficulty. The offline simulation model was built with the double closed-loop method, and the simulation tests were conducted under different gear shift conditions. The results show that system controller meets with the corresponding requrments and possesses a good ability on operational coordination.Finaly, the real time simulation test of electric shift system. In order to further study the control performance of the electric shift system, the open-loop control method was adopted, the shift control strategies were developed, and the real-time simulation model of system controller was built through the hardware and software platform of dSPACE and MATLAB/Simulink, and the real time simulation test under the different working condition were implemented through the rapid control prototype test bench of AMT electric shift system. Test results show that the shift control strategies designed are feasible, and the shift controller can realize position control with the shift actuator, and meet with the motion demands, and possess a good ability on operational coordination.