Stability under Sensor or Actuator Failures

We consider the standard linear, time-invariant, multiinput multi-output unity-feedback system with possiblc failures in the sensor or actuator-connections. We parametrize the set of all controllers such that the closed-loop system is stable when sensors or actuators fail. We consider two classes of failures: the failure of one connection and the failure of any number of connections provided that at least one connection does not fail. The general parametrization requires knowledge of the failure to update the stabilizing controller. For plants which can be decoupled, we also give a class of controllers which ensure stability under any sensor or actuator failures without updating for different perturbations.