Analysis of order of redundancy relation for robust actuator fault detection

This paper presents a new approach, called robust nonlinear analytic redundancy (RNLAR) technique to actuator fault detection for input-affine nonlinear multivariable dynamic systems. Robust fault detection is important because of the universal existence of model uncertainties and process disturbances in most systems. This paper characterizes the order of redundancy relation for nonlinear systems in terms of robustness. A theorem is proposed that state an increase in the order of redundancy relation increases the robustness in the sense of a performance index defined in this paper. Experimental results on a PUMA 560 robotic arm are presented to demonstrate the application of the theorem.