Delay-based signal shapers and acfa 2020 blended wing body flight control system

¹ Czech Technical University in Prague, FEE Department of Control Engineering Prague, Czech Republic
² Czech Technical University in Prague, FEE Center for Applied Cybernetics Prague, Czech Republic

Abstract

The purpose of this paper is twofold. First: results related to application of signal shapers, imposed on pilot's commands, in cooperation with feedback flight control system (FCS) are reported for the case of ACFA2020 (Active Control for Flexible 2020 Aircraft) blended-wingbody (BWB) design. The results suggest that signal shapers can cooperate nicely both with FCS focused on the rigid-body dynamics only, as well as with an implemented and properly working active damping system. In both cases, the amount of vibrations due to pilot's inputs (manoeuvres) can be substantially reduced. Second: combination of signal shapers and rate-limiters is discussed in detail. Rate-limiters, representing finite achievable rates of servos for control surfaces, deteriorate considerably performance of the delay-based shapers. Configuration proposes only open-loop response of the free aircraft (without controller) for shaped reference respect to nonlinearities at action surface. Standard versions of the shapers cannot be therefore directly applied, especially for higher control surfaces deflections. Instead, two efficient alternatives can be used, suggested in the paper, that take the rate limitations into account at the design stage already.