Abstract: The heavy Automatic Hydraulic Transmission (AT) vehicle as research object,based on existing traditional shift strategy,on the basis of the analysis of the problems caused by traditional shift strategy on slope,the driver′s intentions were considered fully,a fuzzy adjustment slope shift strategy was devised by using multiple control parameters.According to the parameters of the prototype,the simulation model of vehicle shift was established and the situation of continuous ramp was simulated.Finally,the road test of AT vehicle was carried out.The results of simulation and test showed that,the fuzzy adjustment slope shift strategy can solve the problems caused traditional shift strategy,improving the traveling performance of AT vehicles on slope.

Key words: Automatic Hydraulic Transmission(AT), slope shift strategy, fuzzy control