Study On Starting And Shifting Control Of Wet Double Clutch Transmission

Double clutch transmission, as the world's most advanced transmission products, good structural inheritance for manual transmission, high machinery efficiency, broad applicable scope, becoming the focus of companies competing to develop. DCT related research has become a hot issue in the world auto industry, so this article carried out intensive on the DCT-control study, has well practical significance.Starting and shifting technology is the key of DCT control systerm, so this article is aimed at clutch control technology of starting and shifting, for in-depth research and discussion,for independent research core technologies,have a good reference value on DCT in domestic.In this paper, dual-clutch transmission starting and shifting control strategy as the core, how to build intelligent control system of the clutch pressure, work out two clutch control strategy of starting and shifting process, make an in-depth study.Two key components of dual-clutch control is the clutch pressure control valve and wet clutch, clutch pressure control valve is the most critical parts in clutch pressure control system, clutch pressure control valve adopts high precision of VFS (Variable Force Solenoid) valve in DCT, by putting bar make the electromagnetic force directly feedback to the valve spool, with high accuracy, fast response advantages, study on wet clutch torque transfer property, has a vital role to improve the quality of clutch torque control, with the introduction of the clutch oil temperature, friction plate relative speed, hydraulic oil viscosity and other parameters to improve the accuracy of clutch torque model, make the theoretical basis for the realization of precise control of clutch transmission torque.CMAC is based on local approximation and simple and fast artificial neural network, and is similar to perception associated memory method, to be able to learn any multidimensional approximation nonlinear mapping. unlike traditional neural networks and other global approximation methods, CMAC is a local approximation, each modification to fewer values, fast learn speed, suitable for very high requirements in the field of real-time control, with a certain degree of generalization ability, tthe similar input has the similar output, easy to achieve in SCM and other control system with low floating calculate ability, very fast respond. Therefore this paper make core as CMAC, combined with the fuzzy control theory, build an intelligent control system of clutch pressure. This system has an adaptive ability, high control accuracy, easily for hardware implementation. And through simulation and testing, verify the validity of the system, provide a powerful means of starting and shifting control.The DCT hasn't torque converter, solely on the clutch slipping get smooth start, the start process's slip control becomes the exceptionally important, wet clutch torque characteristic is very complex, the influencing factor is numerous, driver's action of various styles, requires the DCT starting control system can be adapted to various start conditions, realizes the intellectualization, with robust and adaptable, be able to respond quickly to parameters changes, in order to ensure access to good starting characteristics. Takes two forward gears at the same time to participate in the starting process, use control means to prevent low-speed load alternate impact, implementation of a vehicle's smooth and fast starting. Described in detail calculate method of target torque in the various stages of starting process, and through test, verify the validity of the starting control strategy.Two clutch switching control is DCT's key technologies in shifting process. The principle of shift process in DCT works the same as AT, but the structure is very different, AT has a hydraulic torque converter and one way clutch, so has excellent shifting characteristics. DCT hasn't such accessories improve shift quality, requires more accurate during two clutch switching in shift torque control, shifting control strategy for a more precise, need software systems to compensate for the disadvantages of hardware.This paper described in detail of calculation for two clutches target torque in shifting process, and through test, verify the validity of the shifting control strategy.By theoretical analysis of starting and shifting process, simulation and test, following results were obtained.â‘ Established mathematical model for clutch pressure control valve and the clutch torque characteristics;â‘¡Established clutch pressure intelligent control system based on Fuzzy CMAC;â‘¢Formulated starting control strategy and has been validated through test;â‘£Gives a method of comprehensive shift schedule and preselection schedule, develop shifting control policy of different conditions, and has been validated through test. This article has innovation in the following areas:â‘ Established a model-based intelligent fuzzy CMAC clutch pressure control system, quickly respond, highly adaptive, easily achieve on current hardware conditions;â‘¡Presented destination torque calculation method of starting process based on torque control, tests proved that the method can achieve smooth and fast starting;â‘¢Gave a calculation method of preselection law, made preselection law had a theoretical basis;â‘£Presented the method to calculate clutch target torque based on torque control in process of shifting,tests proved that the method can achieve smooth shifting.