Control Strategy of Shuttle Shifting Process of Agricultural Tractor During Headland Turn

Tractor-implement combination generally involve the forward and reverse motion to perform the required task, which causes the tractor to frequently change its direction of movement. Automating the shuttle shifting process can reduce the labor intensity of the driver and improve the field efficiency and comfort. In this study, a power shuttle motion inverter is designed with a planetary gear train and clutch/brake. The dynamics model of the tractor power-train and a simulation model are established. Two types of the shuttle shifting process are designed and analyzed by the lever analogy method. To improve the shifting quality, control strategies for the shuttle shifting processes are formulated by analyzing the changing characteristics of the force exerted on the tractor-implement combination during the shifting processes. The analysis results show that quick and comfortable shuttle shifts are achieved during the process of moving from the forward to reverse directions and vice versa.