Transmission shift controller design based on a dynamic model of transmission response

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Transmission shift controller design based on a dynamic model of transmission response

Quan Zheng / Srinivasan, K. / Rizzoni, G.

The advantage of model-based controller design is demonstrated in this work. A model-based approach identifies the dominant factors in the transmission shift response and leads to a straightforward controller design. In this case, a fixed gain controller works fine and the controller is quite robust. It is also demonstrated that improved dynamic models of transmission behavior can lead to an improved control of shifts and, furthermore, will lead to better understanding of how transmission dynamic behavior depends on its design. Shifts involving clutch-to-clutch load transfer or rapid pressurizing of the input clutch as in neutral-idle transitions require higher responsiveness of the system. In these applications, direct manipulation of the clutch pressure is desired in order to achieve a fast and wellbehaved response. Indirect control of clutch pressure by manipulation of the accumulator backpressure is generally unacceptable in such cases. A better approach involves eliminating the accumulator, and modulating opening area of the orifice, which poses a challenging controller design problem. Shift control is not restricted to inertia phase control. Torque phase control is also important if the output shaft torque variation during this phase is to be limited. Simultaneous and independent control of the output shaft torque during both the torque and inertia phases and of the turbine speed during the inertia phase requires coordination of engine and transmission control functions to achieve satisfactory control. Model-based control for such cases is also a challenging controller design problem.$