Aircraft spiral dive attractors due to actuator saturation

Robust gain-scheduling H∞ control of uncertain continuous-time systems having magnitude- and rate-bounded actuators: An application of full block S-procedure

“…The magnitude, and especially the rate bounds of the actuator, are identified as a serious source of undesirable transient response and may even cause closed-loop instability and poor performance in several industrial applications [24,44]. For instance, rate saturations on the control surfaces caused YF-22 to crash in 1992 [13,1,8,45]. Other practical examples of control systems in which actuator saturations appear as a major reason for instability can be given as engine compressors [49], stabilization of ships by using active fins [27] and reactors having slow actuators [10].…”

Robust disturbance rejection for discrete-time systems having Magnitude and rate bounded inputs

“…They may cause fatal effects in several situations such as the crash of YF-22 in 1992, which has been caused by pilot-induced oscillations due to rate saturated control surfaces. Details about these incidents can be found in the references [1], [2], [3] and [4]. Other examples of practical problems in which the magnitude and rate bounded actuators create a source of performance degradation and instability can be listed as the control of jet engine compressors [5], general reaction processes having sluggish actuators [6] and stabilisation of ships using active fins [7].…”