15th Triennial World Congress of the International Federation of Automatic Control
  Barcelona, 21–26 July 2002 
PRACTICAL STABILIZATION OF A CLASS OF NONLINEAR PLANTS WITH UNCERTAIN INPUT AND OUTPUT NONLINEARITIES
M.L. Corradini** G. Orlando*
* Università di Ancona, via Brecce Bianche, 60131 Ancona,
Italy.
** Università di Lecce, via per Monteroni, 73100 Lecce, Italy.

This paper addresses the stabilization problem of “sandwich systems”, i.e. intrinsically nonlinear and uncertain SIMO plants containing simultaneoulsy either backlash and dead zone in the actuator and dead zones in sensors. The proposed controllers, based on sliding mode control, have been shown to achieve state (hence output) boundedness. The rationale followed in control design consists in ensuring the achievement of a sliding motion which, in turn, guarantees the attraction of the state vector towards a boundary layer, whose maximum width depends on the uncertainty on output measurements caused by the presence of unknown deadzones in sensors. Furthermore, the control laws have been designed as to simultaneously guarantee also the avoidance of actuator nonlinearities, ensuring that the ‘forbidden region’ of dead zones and backlash are never entered, even in the presence of uncertainties. Simulation results show the effectiveness of the proposed controllers.
Keywords: Robust control, Actuator nonlinearities, Sensors Nonlinearities
Session slot T-Tu-E08: Stabilization III/Area code 2c : Non-linear Systems