Innovative Gain Reconfiguration for Active Fault-Tolerant Flight Control: Balance of Stability and Agility

TL;DR

This paper introduces a novel reconfigurable fault-tolerant flight control strategy that enhances safety by maintaining stability and agility during actuator faults through incremental attainable acceleration sets and adaptive gain updates.

Contribution

It presents a new approach for real-time reconfiguration of flight control gains using incremental attainable acceleration sets and an analytical outer-loop gain update law.

Findings

Successfully maintains stability during severe actuator faults.

Outperforms fixed-gain control approaches in agility and robustness.

Demonstrates effectiveness in demanding maneuver scenarios.

Abstract

In this study, a distinct reconfigurable fault-tolerant flight control strategy is addressed for mitigating one of the persistent safety-critical issue, i.e. loss of control triggered by actuator faults. The attainable acceleration set notion is taken a step further towards incremental attainable acceleration set through a slight modification that enables instantaneous controllability checks. The inner-loop gains are updated in case of a fault using incremental attainable acceleration set and a tuning function, which is in charge as a compensator of agility and robustness. Additionally, the outer-loop gains are also such reconfigured that holding the bandwidth ratio of the successive loops at a prudent level to ensure the closed-loop stability; for this reason, an analytical outer-loop gain update law is derived based on the inner-loop gains and bandwidth, actuator and command filter time constants. Subsequently, the proposed architecture is assessed under a severe fault scenario with a demanding maneuver mission. Noticeably, the proposed method fulfills the expectations of stability and agility sufficiently, and surpasses the fixed-gain approach.