Research On Dynamical Performance And Control Strategy For Electro-mechanical Continuously Variable Transmission System

The continuously variable transmission is an ideal vehicle transmission. It is a very important significance of whole vehicle performance that the system dynamic characteristics and controlling the shifting process are study. In the process of the developing electronics metal-belt continuously variable transmission (EM-CVT) which is our designed, the paper is focusing on the dynamic characteristics and control problems of the start clutch device, the governor pressurizing mechanism and variable speed system.The innovation of this paper is that a fuzzy control rules for dry friction clutch system control under vehicle starting station, and a fuzzy PID algorithm for EM-CVT speed ratio control strategy are proposed. The first analysis of the structure and performance of the invention EM-CVT, EM-CVT powertrain system dynamic mathematical model to study the dynamic characteristics of the the governor pressurized systems and automatic clutch system. Secondly, the clutch control strategy in considering the intention of the driver, the vehicle driving conditions and the degree of the impact of the bonding process and the friction work and other factors, the design of the starting clutch fuzzy control rules. Speed ratio control strategy, including the condition of the vehicle identification, control algorithm and the governor pressure system control to work condition of three parts:the condition of the vehicle identification combined with the intention of the driver, vehicle dynamic characteristics, the use of fuzzy recognition technology to build a fuzzy recognition model; division the condition control algorithm based on the recognition result, the engine operating characteristics of the driver’s intention to target speed ratio; reduce the steady-state error in order to obtain the actual speed ratio and target speed ratio follower, design fuzzy PID ratio control algorithm to quickly follow the change of the target ratio.This paper the use of computer simulation, the dynamic characteristics of the EM-CVT speed ratio, the relationship of the slip characteristics and the executive power and the transmission ratio, as well as control strategies and EM-CVT ratio control strategy for debugging and verification of the automatic clutch system, under the situation of meeting the impact degree requirements, it is have the smaller the friction, which are demonstrate that this system has good speed ratio following performance, and EM-CVT powertrain system has a good dynamic response characteristics. Complete each controller hardware and software design, to build a bench test and loading test. In the engine to completion of the transmission gear efficiency in economic conditions and dynamic conditions, the transmission ratio, torque, and slip and other experiments, and data processing, access to the transmission ratio to the displacement relationship with the tapered axle, engine speed and efficiency Instantaneous state characteristics, transmission ratio change characteristics; loading test was clutch characteristics. Through simulation and experimental validation of the reliability of the transmission structure, and the feasibility of the control strategy.The results of this research provide a valuable reference for the study on the continuously variable transmission control and the vehicle starting control.