A cascade regulator using Lyapunov's PID-PID controllers for an aggregate actuator in automotive applications

This paper deals with a hybrid actuator composed by a piezo and a hydraulic part and with a cascade PID-PID control structure for camless engine motor applications. The idea is to use the advantages of both, the high precision of the piezo and the force of the hydraulic part. In fact, piezoelectric actuators (PEAs) are commonly used for precision positionings, despite PEAs present nonlinearities, such as hysteresis, saturations, and creep. In the control problem such nonlinearities must be taken into account. In this paper the Preisach dynamic model with the above mentioned nonlinearities is considered together with cascade PID-PID controllers combined with a feed-forward action. In particular, the hysteresis effect is considered and a model with a switching function is used also for the controller design. Simulations with real data are shown.