Research On Loader's Lockup Clutch Control System For Hydraulic Torque Converters

Loader meet the requirements of smooth start and shift,easy to operate,and to prevent overload shutdown in the process of driving.Nowadays,the use of hydraulic torque converter is increasingly widespread,but some ploblems that the torque converter has a lower transmission efficiency,larger fuel consumption still exist.The research shows that the locking clutch can improve the transmission efficiency and reduces the energy consumption effectively.Therefore,the research of the locking clutch and its control technology have been paid more attention by some major vehicle manufacturers.According to many years' research and development experience of Guizhou's automatic hydraulic transmission manufacturer and in order to improve the performance of shifting gears,the advanced control method in the control of the lock-up clutch is adopted and further theoretical research is needed.Based on the relevant parameters under various working conditions,"intelligent" locking control models are established.The research of this paper provides technical supports and theoretical references for the development of high-performance control system for automatic hydraulic transmission production enterprises,and for improving the transmission efficiency of loaders and reducing energy consumption.Based on the theoretical analysis of a hydrulic torque converter in this paper,some parameters such as the maximum power transfer point,speed distribution areaes and the fuel consumption rate were obtained by analyzing the matching characteristics of the input and output work of raw parameters of the engine and torque converter.The parameters of engine and torque converter were optimized by genetic algorithmand a reasonable matching region was obtained.Based on the basis of matching analysis of the engine and the torque converter,the hydraulic-electronic control system of the lock-up clutch was designed,and the control law of the lock-up clutch was studied with the actual working demand of the loader.The turbine speed and the shift signal were the main control parameters,and a multi-parameter locking law were established through the auxiliary parameters such as the accelerator pedal signal,the brake signal,the steering signal.The lock control flow chart was designed based on it.Based on the concept of model design and using TMS320F28335 master chip,a model was obtained by the Stateflow module in the Simulink and a variable duty cycle was obtained by CCS3.3 and Simulink joint simulation obtain.Varified the oil pressure can be changed of the hydraulic system through controlling the duty cycle to achieve locking and unlocking control of locking clutch.By analyzing the composition of the sliding friction control system of the lock-up clutch control and the control principle of sliding friction,the mathematical model of the system was established.Based on the analysis of the principle of sliding friction,the hydraulic circuit which is controlled by lock-up clutch contact chamber and the release chamber has been researched.The fuzzy PID control and conventional PID control algorithm for the control effect of sliding friction were simulated and compared The fuzzy PID control method which was used for sliding friction control was put forword.