A cascade controller structure using an internal PID controller for a hybrid piezo-hydraulic actuator in camless internal combustion engines

This paper presents a hybrid actuator composed by a piezo and a hydraulic part and with a cascade PI-PID-PI control structure for camless engine motor applications. The idea of this contribution is using the advantages of both: the high precision of the piezo and the force of the hydraulic part. Piezoelectric actuators (PEAs) are mostly used for precision positioning, despite PEAs present nonlinearities, such as saturations, hysteresis and creep. In the control problem this kind nonlinearities must be taken into consideration. The Preisach dynamic model with the above mentioned nonlinearities is considered along with a cascade PI-PID-PI in this contribution. 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 presented.