Research On Control Strategy And Test Of AMT Of Commercial Vehicle

Automated Mechanical Transmission(AMT)is improved based on the traditional andmanual mechanical transmission and is one of the most widely used automated transmissions,which is characterized by high transmission efficiency, simple construction, low cost andhigh cost performance. Besides, it fits most vehicles and is suitable for the developmentstatus of commercial vehicle industry with good prospect of industrialization and broadmarket. In this thesis, combining with the major project of “AMT of commercial vehicle” ofthe technical center of FAW, in-depth research is made on actuator selection、automaticclutch control and gear shift schedule of AMT of commercial vehicle, and verify the researchresults in the car.In this paper, the main contents are as follows:1The concrete structure and operating principle of the actuating mechanism of clutchand that for selecting and shifting of AMT of Commercial Vehicle are expositioned,simulation software of SimulationX is applied to construct the simulation model for AMTsystem of Commercial Vehicle. Then the simulation results and bed test results arecontrasted, which demonstrates that this model is accuracy and can provide guidance to thestructure optimization design of actuating mechanism.2Focus on commercial vehicles AMT starting and shifting stage of the clutchengagement process. Closed-loop control of the clutch position is applied at the startingstage of Commercial Vehicle AMT and the set point of the object position of clutch isdetermined by accelerator pedal position and engine speed-drop; Clutch open-loop controlleris applied at the shifting stage and reference variable is the engine torque. Furthermore, thereare several important factors for the automatic control technology of clutch that need to beanalyzed; they are the monitoring of clutch half joint, self-regulation of clutch position andover-load protection of clutch. 3The optimum gear stage is determined according to vehicle state, road status andintention of the driver. Firstly, acceleration approach is applied to design the dynamic gearshift schedule of AMT of commercial vehicle and then fuel consumption is taken as the basisto design the economic gear shift schedule. After that, considering the influences of drivingintention, vehicle state and road status, longitudinal acceleration transducer method isapplied to estimate the road grade and the driving equation and the dynamic signal acquiredby the real vehicle are applied to estimate the weight with full equipments to determine thegear shift schedule of AMT of commercial vehicle that adapts to various working conditions.Finally, high-level simulation analysis software of CRUISE is utilized to build the model ofAMT of commercial vehicle, economy shift schedule have been optimized to improve use ofits GSP, so as to enable them to balance the needs of the economy and emissions.4Proyotypes and real vehicle test method validation AMT control strategy. Firstthrough clutch actuator and select/shift actuator bench test to verify the reliability. Duringthe following AMT vehicle control performance tests, starting test, start-stop test, and testfor creep on the level road and shifting test under different accelerograph openings areconducted, validating the feasibility and reliability of control strategy of clutch andautomatic gear shift schedule. The test results show that the control strategy of the AMTsystem of commercial vehicle is satisfactory.