A design of fault-tolerant servo systems against sensor failures

This paper concerns with a design of fault-tolerant servo systems against sensor failures. This paper proposes to use saturation devices to block undesirable ramp signals generated by integrators. This paper clarifies that unintended saturations make the closed-loop system unstable, even if the controller is appropriately designed for the simultaneous stabilization problem. And it is shown that the row diagonal dominance is required to avoid such unintended saturations. Then, the paper proposes a controller structure which consists of a decoupling gain, a diagonal integral gain, and a full matrix stabilizing controller. A numerical example demonstrates the effectiveness of the proposed controller structure.