Reliability increasing through networked cascade control structure – consideration of quasi-redundant subsystems

The paper presents common cascade control architecture where specific kind of redundancy could be considered. There are different approaches how to increase the reliability of networked control systems. Common approach uses redundant components in control system i.e. passive or active redundancy. We deal with quasi-redundant subsystems (shared redundancy) which could be very useful when critical failure appears. This type of redundancy offers several important advantages such as minimizing the number of components as well as reliability increasing. The example of a four-rotor minihelicopter is presented where a cascade control architecture is considered. The main contribution of this paper is that it helps to determine the applications where quasi-redundant subsystems are a good solution to remain in a significant reliability level even if critical failure appears. (Copyright IFAC 2008).