Disturbance Accommodating Control of an Automotive Transmission Torque Converter Clutch System

Abstract

Modern automotive drivelines are facing increasing pressure to improve overall efficiency while maintaining vehicle comfort and performance. This thesis presents several new ways to control the torque converter clutch in an automotive automatic transmission in such a way they improve driveline system efficiency while maintaining its comfort. This efficiency improvement is accomplished by extending the clutch’s application conditions to a lower speed where the environment is harsher than is possible with the current class of controllers. Three new model-based methods are evaluated on their ability to control the simplified model of a torque converter clutch. These controllers include one-step-ahead and complex observe based controller methods. These controllers are applied in the presence of large disturbances that include parameter uncertainties and unmeasured state errors to evaluate their robustness in these environments. The lack of clean sensor measurements highlights the limitations of the one-step-ahead method and are demonstrated by the controller's inability to maintain system regulation in this high noise environment. Because it is not practical to accurately measure the torques and internal speeds of the torque converter system, this research addresses this by estimating them using observers. Using these new observer-based-control methods, this dissertation presents the simulation results that demonstrate this method provides a significant increase in robustness to disturbances. The precise and smooth tracking of the regulator's setpoints highlights the system's ability to meet the powertrain's comfort and economy targets, while being practical enough to be implemented in current automotive systems