Down shift control with power of planetary-type automatic transmission for a heavy-duty vehicle

Gear-shift with power belongs to one of the most important advantages of the planetary transmission for heavy-duty vehicles. However, there is no power transmitted from the engine to the driving wheels since the accelerator pedal is released completely in the most down shifts, and the previous research mainly focused on up shift with power corresponding. In contrast, down shift with power can be useful for the improvement of shift quality as well as vehicular safety and drivability for heavy-duty vehicles. The model of power train is build and a control methodology for down shift with power is presented based on the modelling dynamic analysis. Adaptive sliding mode control for better robustness is formulated and the turbine speed with fixed changing rate is chosen to be the controlling ideal reference trajectory. Finally, heavy-duty vehicle with full load based tests of climbing in mountains are conducted, and the results indicate that the proposed down shift with power control strategy can improve the shift quality and the vehicular performance. ? 2021 Elsevier Ltd. All rights reserved.