A Baseline Nonlinear Flight Controller Design Approach With A Shorter Design Cycle Time For a Fighter Aircraft

Abstract

In this paper, a framework for designing a baseline full envelope flight controller  for the stability augmentation of an unstable fighter aircraft  is presented. The flight dynamics assesments for these aircrafts are normally carried out using both off-line and real-time simulations. The framework, referred to here as  Simplified Nonlinear Dynamic Inversion (SNDI), results in significant reduction in the overall  design cycle time. The SNDI based controller produces  simultaneous control allocation and decoupling in the time domain. The Aileron to Rudder Interconnect (ARI) gain which is commonly used for the lateral-directional control decoupling is generalized here for an aircraft with multiple redundant controls. The off-line simulations and simulator based pilot evaluations carried out for the assessment of aircraft dynamics enable an early comparison between different  candidate configurations to narrow down to  the final choice of the design configuration  in a short time. 

The proposed approach is illustrated using the model of Aero Data Model In Research Environment (ADMIRE) delta canard fighter aircraft.  Offline simulation results show that the proposed controller design achieves a similar performance when conmpared to that of other existing controllers available in open literature that are designed based on a conventional approach. The proposed design is carried out  in a shorter   span of design cycle time and meets all the design specifications considered.