Clutch slip control of Automatic Transmission using nonlinear method

To improve the shift quality of vehicle with clutch-to-clutch gear shifts, a nonlinear controller is designed for the clutch slip control during the shift inertia phase of an Automatic Transmission (AT). Backstepping technique is used to deduce the control algorithm. Model uncertainties including steady state errors and unmodelled dynamics are also considered as additive disturbance inputs and the controller is designed such that the error dynamics is input-to-state stable (ISS). Lookup tables, which are widely used to represent complex nonlinear characteristics of engine systems, appear in their original form in the designed clutch slip controller. Finally, the designed controller is tested on an AMESim powertrain simulation model. Comparisons with an existing linear algorithm are given as well.