Design of a robust controller for shift control of an automatic transmission

Abstract

A robust controller is proposed for the clutch-to-clutch shift of a stepped-ratio automatic transmission. The control strategy consists of three parts: a feedback controller is derived using µ synthesis, which guarantees the system robustness; a feedforward controller is designed to improve the tracking performance; a disturbance compensator is used to reduce the effect of the disturbance on the system output. Finally the designed controller is tested on a powertrain simulation model, which contains a complete drivetrain and clutch actuators. It is demonstrated that the controller is robust against uncertainties in the parameters and variations in the driving conditions. Moreover, discrete implementations with a sampling time of 10 ms show the potential of the proposed controller for use in real vehicles.