Research Of Clutch Engagement Control Strategies For Internal Combustion Forklift AMT System

Forklift is an important logistics and material handling tools, traditional internal combustion counterbalanced forklift operated complex in the process of starting and shifting period, easily lead to driver's driving fatigue. Automatic mechanical transmission (AMT) is transformed from the traditional clutch and manual gear transmission, the main changed were the clutch pedal control by feet and manual shifting two parts, that is, in the case of the overall structure of the transmission remains unchanged, using electronic control method to achieve the features of automatic clutch and gear shifting. This thesis mainly studies the design and control strategy of the AMT, the main contents include:Design the AMT scheme of forklift. Firstly, determine the structure of AMT program, and explain how it works; secondly, design the data acquisition programs for each sensor; and finally, design the scheme of AMT clutch and transmission actuator.Research on the clutch engagement processes of the start-up and shifting of forklift. Firstly, the law of clutch engagement during start-up and shifting processes were analyzed so as to get the factors that affect the clutch engagement; Then research on the dynamic model of the clutch engagement, the calculation formula of the friction and jerk of the clutch engagement is derived, analyzing how to make a balance between the two conflicting evaluation indicators of friction and jerk.The study on fuzzy control strategies. The engagement of clutch was affected by the driver's intention and forklift's operation conditions, these factors constitute a nonlinear, time-varying, difficult to achieve precise control of mathematical modeling system, for these features of the system, fuzzy control strategies was proposed, and the design of the fuzzy controller for the start-up and shifting processes of forklift is accomplished by means of the MATLAB platform. Finally, using of GUI make a simulation and analysis of the fuzzy control strategies.Prototype test results showed that:the proposed fuzzy control strategies was achieved the intended purpose, the forklift AMT could achieve automatic engaging and shifting functions, the controller could adjust the control strategies timely according to the driver's intention and forklift's work conditions.