Design of fault detection and diagnosis systems (FDDS), although extending the control strategies, they are challenged by controller interferences in fault diagnosis. In this study, in order to improve performance and accuracy of FDDS in the fault detection process, considering influential parameters and the level of corresponding interferences is investigated. To achieve this enterprise, a powerful method in fault pattern recognition of industrial plants based on dynamic behavior and dynamic model by using soft computing is designed and tested on simulated suspension system of a vehicle. The suspension system is one the parts, most affecting reliability and safety of the vehicle. For investigating the level of interference caused by the control unite, the simulations of both passive and active (equipped with hydraulic actuator) suspension systems are utilized in association with the control unite. The results of tests under variable circumstances (using random values) demonstrate that the presence of control unite, strict the FDDS process and reduces the robustness of the system against disturbances and noise. Considering the way in which the control unite affects the process, application of suggested solutions in this research, have a considerable impact on amendment of the adverse effects.
Fault detection program which is provided by Matlab software benefits special possibilities to investigate and define the effect of controlling unite and can be considered as a useful device to facilitate and precipitate conduction of tests in different stages of the research.