Damage-mitigating control with overload injection: Experimental validationof the concept

The goal of damage-mitigating control is to enhance structural durability o f mechanical systems (e.g., advanced aircraft, spacecraft, and power plants ) while retaining high performance. So far the reported work in damage-miti gating control has focused on reduction of peak stresses to increase struct ural durability. This paper presents a novel concept that takes advantage o f the physical phenomenon of fatigue crack retardation. Overload pulses are intermittently injected into the plant as a feedforward signal through the actuator(s) in addition to robust feedback control. A feedforward sequence of limited overload pulses and a robust feedback control. A feedforward se quence of limited overload pluses and a robust feedback control law are des igned based on state-space models of fatigue-crack damage and plant dynamic s. A series of experiments have been conducted on a laboratory test apparat us to demonstrate feasibility of the overload injection concept for robust damage-mitigating control.