Non-smooth observer for sandwich systems with dead-zone

In control engineering practice,many systems involving dead-zone can be described by the so-called sand-wich systems with dead-zone.In this paper,a novel non-smooth observer is proposed to handle the state estimation for the sandwich systems with dead-zone.Based on the characteristics of the system,a non-smooth state-space equation is con-structed by the separation principle;and then,a non-smooth observer is developed based on this state-space equation.The observer can be switched among different operating zones automatically according to the change of operation conditions.The convergence theorem of the non-smooth observer and its proof are given respectively.Simulations are performed.The comparison of simulation results between the proposed non-smooth scheme and the conventional method is illustrated.It shows that the proposed non-smooth approach is much better than the conventional one in estimation performances.