Irrigation channel stability under arbitrary feed-forward link failures

In this paper we study the decentralized control configuration for water level control with added local feedforward (FF) control. The water level control application is a practical example where the use of communication hardware is inescapable. Therefore in our study we consider that on occasions the FF loops will be rendered ineffective due to the inability of the related communication channels to transmit at the required times. We consider first the case in which some FF loops are not operational for a long time (static failure configuration) and propose a stability analysis that shows that as long as the original feedback decentralized control is stable the overall configuration, including the possibly failing FF links, will remain stable. We then consider the more challenging case of time-varying faults on these FF loops and their effect on the overall stability of the system and finally the more general case in which the control action can be FF to all upstream controllers, not just the adjacent one.