Intelligent Control Technology Of Vehicle Dual Clutch Transmission And Study On The Virtual Test System Of DCT Electronic Control Unit

Dual-clutch transmission (DCT) which has the intrinsic advantages in high efficiency and low production cost eliminates torque interrupts during gearshift through one clutch separated while another clutch engaged, so that the vehicles can run as smooth as one using an Automated Mechanical Transmission (AMT). Product line of manual transmission (MT) which is widely applied in transmission market of our country can be used to design and manufacture DCT, which is in favor of the upgrade from MT to automatic transmission and coincide with the situation of our country. Nowadays, the researches and application of DCT vehicle are still at an early stage, the study on key technology of DCT is a good chance to pursue the advanced automatic transmission technology of the world is provided to us.To satisfy the dynamic performance, fuel economy of the vehicle and diversification of product demand, the intelligent of electronic control unit has more and more intelligence,and it is more difficult to be developed. Conventionally, electronic control units of vehicle are developed and tested using open-loop testers and prototype vehicles. The final system's validations are also performed in prototype vehicles at various geographical locations. This is not only expensive but also time consuming and inflexible. Virtual test technology can accomplish tests rapidly, shorten developing time and save study expense. Based on a virtual test bench, ECU's performance can be examined and evaluated, and the system can play an important role in studying and developing the ECU with higher efficiency and lower cost.In this paper, intelligent control technology of DCT and the virtual test system of DCT electronic control unit are carried out relying on a project of National High-tech R&D Program (863 Program)"Development of high performance automatic transmission for economical car". The main work as follows:①Dynamic characteristic of DCT during vehicle running are analyzed, and the its dynamic model are built. Theory and characteristic of electronic throttle are analyzed, and the nonlinear model of electronic throttle is described. The BLDC motor-driven dry dual clutch actuator is studied, the mathematical model has been established for the system. Focus on the nonlinearity and time-varying properties of engine, a novel engine identification model is proposed based on support vector machine (SVM). The model is based on engine test data and structure risk minimization (SRM) principle. It has very good generalization ability. Using the MATLAB,many precision influencing factors of engine torque are analyzed, and the precision influencing sequence of these parameters is confirmed. Considering the interaction among the parameters, the optimal parameters of SVM engine model is found out using loop nest program method.②Study on the intelligent control architecture of DCT. The overall electrical control system program and the electronic control system hardware and software structure are determined, the motor and the sensors are selected. A hierarchical intelligent control software system of DCT is proposed。A three-level controlling architecture which consists of perception layer, control strategy layer and execution layer is built. Signal processing algorithm of DCT perception layer based on abnormal data deletion, digital filtering and measure algorithm is described in detail.③A sliding mode controller(SMC) for clutch actuator is designed based on the actuator nonlinear dynamic mode. In order to alleviate the chattering phenomenon of SMC and uncertainty of actuator, an adaptive fuzzy logic based sliding mode control (AFSMC) is proposed. The stability of the control system and convergence of clutch actuator position tracking errors are guaranteed by Lyapunov stability theory. Simulation results show that the proposed control system can achieve favorable tracking performance and robustness with regard to parameter variations and external disturbances.④Research of intelligent control technology during DCT vehicle starting. The engaging process of the clutch is analyzed, clutch starting strategy based on fuzzy control which comprehensively considers the driver intention, engine running state and clutch engaging state is presented. Then, fuzzy control parameters are selected and fuzzy control logic rule is presented. The simulation results prove the correctness of the designed control strategy.⑤Study on human simulating shift schedule. Considering the driver-vehicle-road, the driving expects can be reasoned out by fuzzy control from the driver's intention, electronic throttle opening and relative speed. Dynamic factor is proposed and the design method of human simulating shift schedule is presented. Simulation results show that the shift point alters dynamically according to driver's intentions, human simulating shift schedule can eliminate the improper shifting under special situation, and the shift schedule converts from shift curve to shift area.⑥Analysis on gearshift of DCT. Considering factors jerk and slipping work, based on the jump condition of clutch, satisfying the boundary conditions jerk and slipping work, quantitative formula of clutch engagement timing sequence is presented. It provides a design method for developing an intelligent vehicle with DCT.⑦The research of DCT ECU virtual test platform development. According to the scheme of DCT ECU virtual test platform, the ECU virtual test platform was built based on Matlab/xPC Target, MATLAB/Simulink, Matlab/RTW and Virtual Reality (VR). The platform consisted of test bench, sensors, clutch actuators, electronic throttle, real-time platform, signal collecting system and software system. The system feature low cost, more versatility, man-machine interaction, virtual reality, proprietary intellectual property rights. Some ECU virtual tests on some conditions were preceded on the platform based on control algorithm prototype. The test simulations showed:①The DCT ECU virtual test proved that the ECU platform was qualified to the test.②The proposed intelligent control strategy of DCT and control algorithm of clutch actuator can well control DCT vehicle under various conditions; for instance, vehicle starting and shifting. Test results show that the intelligent control of DCT is the superior and the virtual test platform features the high efficiency, thus established basic value purport for the proprietary intellectual property rights of DCT.