, AND JÀN LIGU

Abstra t. The paper presents features and implementation of a shared redundant approa h to in rease the reliability of networked ontrol systems. Common approa hes based on redundant omponents in ontrol system use passive or a tive redundan y. We deal with quasi-redundant subsystems (shared redundan y) whereas basi features are introdu ed in the paper. This type of redundan y oers several important advantages su h as minimizing the number of omponents as well as in reasing the reliability. The example of a four-rotor mini-heli opter is presented in order to show reliability improving without using any additional redundant omponents. The main aim of this paper is to show the inuen e of the load in reasing following dierent s enarios. The results ould help to determine the appli ations where quasi-redundant subsystems are a good solution to remain in a signi ant reliability level even if riti al failure appears. Key words: shared redundan y, dependability, networked ontrol systems 1. Introdu tion. To be able to obtain relevant results of reliability evaluations for omplex systems, it is ne essary to des ribe the maximum of spe i dependen ies within the studied system and their inuen es on the system reliability. Dierent methods or approa hes for ontrol systems ' reliability improvement are developed in order to be applied to spe i subsystems or to deal with dependen ies among subsystems. A lassi al te hnique onsists in designing a fault-tolerant ontrol [1 ℄ where the main aim is to propose a robust ontrol algorithm. Guenab and others in [2 ℄ deal with this approa h and re onguration strategy in omple