|Integrated Fault Tolerant Control for Saturated Systems with Additive Faults: A Comparative Study of Saturation Models
Mojtaba Hashemi, Ali Kamali Egoli*, and Mahyar Naraghi
International Journal of Control, Automation, and Systems, vol. 17, no. 4, pp.1019-1030, 2019
Abstract : "In this paper, the integrated design problem of Fault Estimation (FE) and Fault Tolerant Control (FTC)
for saturated systems is considered. The system suffers from input saturation and L2-bounded disturbances. To design
an adaptive observer-based FE, the actuator output measurements are not used, when the actuator is saturated,
there exist new interactions between FE and FTC. In such a case the separation principle for FE and FTC design
does not hold anymore. In this paper, a method is introduced for integrated design of FE and FTC, which guarantees
boundedness stability of such a system. To extract sufficient conditions for stability and minimum L2-gain
performance for disturbance rejection, the Modified Sector Condition (MSC) is employed for saturation modeling.
Also, Quadratic Polytopic Differential Inclusion (QPDI) approach is developed for the comparative study. All conditions
are cast as Linear Matrix Inequality(LMIs) that can be evaluated in a single step. In a numerical example,
the feasibility of the introduced method for stability guarantee is demonstrated and performance characteristics of
FE and FTC in disturbance rejection are compared for both modeling approaches."
Integrated design, linear matrix inequality, observer-based fault tolerant, saturated linear system.