LPV model identification of an EVVT system

Abstract

In this paper, a family of discrete-time system models of an Electric Variable Valve Timing (EVVT) actuator for internal combustion engines under different operational conditions were obtained through the closed-loop system identification, where the complicated EVVT actuating system was treated as a black box. Since it is almost impossible to hold the EVVT cam phasing system at the desired operational condition under open-loop control, closed-loop system identification was adopted. Closed-loop EVVT system models were obtained using the PRBS q-Markov Cover system identification, and with the known closed-loop controller the open-loop system models can be obtained under the given system operational condition such as engine speed, oil viscosity, and battery voltage. The LPV (Linear Parameter Varying) system model was formed based on the obtained family of open-loop discrete-time EVVT models, and the resulting LPV model was further validated by the experimental data. The obtained LPV model is intended to be used for designing the gain-scheduling LPV controllers using the LMI (Linear Matrix Inequality) convex optimization.