Design, modeling and control of a novel architecture for automatic transmissions

Automotive transmissions are required to efficiently transfer power from the engine to the wheels. Automatic transmissions are one of the most widely used transmission systems. This transmission houses a hydraulic system that is used to actuate the clutch system to realize different gear ratios. Currently, these clutches are primarily controlled in open-loop using many valves in a complex control architecture designed specifically for a given transmission system in order to perform precise pressure and flow control. To meet the increasing demand for higher fuel economy, transmissions with greater number of gear ratios are being introduced. The hydraulic architecture is becoming increasingly complicated with more clutches and control elements. With the advancement of MEMS technology, the sensor-based direct feedback control of clutches becomes possible. This paper first analyzes the current architecture of transmission hydraulic actuation and then presents a new architecture for the feedback-based clutches. The proposed architecture is further validated through experiments using a hardware-in-the-loop system.