Tailless aircraft control allocation

Abstract

Abstract : This paper presents a flight controller for a tail-less aircraft with a large suite of conventional and unconventional control effectors. The controller structure is modular to take advantages of individual technologies from the areas of plant parameter estimation, control allocation, and robust feedback control. Linear models generated off-line provide plant parameter estimates for control. Dynamic inversion control provides direct satisfaction of flying qualities requirements in the presence of uncertainties. The focus of this paper, however, is control allocation. Control allocation is posed as constrained parameter optimization to minimize an objective that is a function of the control surface deflections. The control law is decomposed into a sequence of prioritized partitions, and additional optimization variables scale the control partitions to provide optimal command limiting which prevent actuator saturation. Analysis shows that appropriate prioritization of dynamic inversion control laws provides graceful command and loop response degradation for unachievable commands. Preliminary simulation results show that command variable response remains decoupled for unachievable commands while other command limiting methods may result in unacceptable coupled response.