A reduced-order nonlinear clutch pressure observer for automatic transmission using ISS

Abstract

For a new kind of automatic transmissions using proportional pressure valves to control the clutches directly, a clutch pressure observer design method is suggested in the concept of input-to-state stability (ISS). Model uncertainties including steady state errors and unmodelled dynamics are considered as additive disturbance inputs and the observer is designed such that the error dynamics is input-to-state stable. Lookup tables, which are widely used to represent complex nonlinear characteristics of engine systems, appear in their original form in the designed reduced-order observer. Finally, the designed pressure observer is tested on an AMESim powertrain simulation model.

Clutch slip control of automatic transmissions: A nonlinear feedforward-feedback design

“…Fortunately, a pressure observer can be constructed using the measured speed information. Please refer to [13] for detailed discussions.…”

“…Other parameters are defined in Table I and refer to [13] for the detailed modeling process. Due to the extreme complexity of the torque converter and the aerodynamic drag, the nonlinear function in (2) is in general given as lookup table (or MAP), which is obtained by a series of steady state experimentations and contains inherently errors.…”

Observer-based clutch disengagement control during gear shift process of automated manual transmission

“…In [18], for the clutch pressure estimation of ATs, an observer is proposed in the concept of input-to-state stability (ISS) [19][20][21]. The ISS property of the proposed observer is proved, and comparison with a sliding mode observer verifies the potential benefits of the proposed ISS observer in eliminating chatters and in achieving satisfying estimation performance.…”

“…In this paper, the methodology in [18] is extended to design a reduced-order observer for the estimation of the drive shaft torque. A simplified design procedure is given and the estimated drive shaft torque is used for clutch disengagement strategy.…”