Adaptive Shift Control for Automatic Transmissions

Using feedback information of estimates from a model of the hydraulic clutch actuation and measurements from transmission mechanicals, a closed-loop adaptive controller is designed. The controller is structured to update at three different rates: every time instance, every shift, and every n-th number of shifts. Part of the controller is designed to operate in open-loop for the first two regions of the shift until feedback information is available. The open-loop controller adapts within the shift, thus allowing for corrections to the control design to be made during the current shift and in subsequent shifts. The model tuning parameters as well as the return spring pre-load force become the adaptive parameters, which are being adjusted so that the plant matches the model in real-time operation. The control design is validated against a high fidelity simulation model of the transmission hydraulics and mechanicals, as well as experimental data.