Simultaneous stabilization addresses the stability of multiple plants under a single feedback controller. It is desired for aircraft flight control operating under different conditions, when they are represented by a collection of linear dynamic models. The single controller brings continuity and a level of reliability. This paper presents a decomposition approach for the solution to the simultaneous stabilization problem. A bilevel design optimization architecture is adopted in which design of each individual plant (flight condition) is taking place at the bottom level, and the top-level optimization aims for single-control convergence of those individual controllers. Furthermore, performance requirements can be taken into account concurrently with the stabilization process, thanks to the separate bilevel decomposition concept. The effectiveness of the proposed approach is illustrated by different aircraft control system design test cases.
Nomenclaturefeedback control gain p = roll rate, rad/s q = pitch rate, rad/s r = yaw rate, rad/s T e = elevator time constant, s t = time, s u = control vector w = vertical velocity, ft/s x = state vector x = local design variable y = output vector y = coupling design variable z = global design variable = sideslip, rad u = aircraft velocity, ft/s = pitch angle, rad = deflection, rad = eigenvalue = roll angle, rad ! = weighting factor Subscripts a = aileron e = elevator j = jth plant r = rudder SL = system level