scholarly journals Historical Overview of Research in Reconfigurable Flight Control

2005 ◽  
Vol 219 (4) ◽  
pp. 263-275 ◽  
Author(s):  
M Steinberg
Keyword(s):  
Intelligent Control ◽  
Flight Control ◽  
Flight Test ◽  
Historical Overview ◽  
Reconfigurable Control ◽  
Control Laws ◽  
Loop Control ◽  
Software Algorithms ◽  
Lifting Surfaces ◽  
Initial Research

This article presents a historical overview of research in reconfigurable flight control. For the purpose of this article, the term ‘reconfigurable flight control’ is used to refer to software algorithms designed specifically to compensate for failures or damage of flight control effectors or lifting surfaces, using the remaining effectors to generate compensating forces and moments. This article will discuss initial research and flight testing of approaches based on explicit fault detection, isolation, and estimation, as well as later approaches based on continuously adaptive and intelligent control algorithms. In addition, approaches for trajectory reshaping of an impaired aircraft with reconfigurable inner loop control laws will be briefly discussed. Finally, there will be some discussion on current implementations of reconfigurable control to improve safety on production and flight test aircraft and remaining challenges to enable broader use of the technology, such as the difficulties of flight certification of these types of approaches.

Design of Dynamic Inversion and Explicit Model Following Flight Control Laws for Quadrotor UAS

2020 ◽  
Vol 65 (3) ◽  
pp. 1-16
Author(s):  
Umberto Saetti ◽  
Joseph F. Horn ◽  
Sagar Lakhmani ◽  
Constantino Lagoa ◽  
Tom F. Berger
Keyword(s):  
Flight Control ◽  
Flight Test ◽  
Parametric Model ◽  
Unmanned Aerial Systems ◽  
Model Parameters ◽  
Dynamic Inversion ◽  
Explicit Model ◽  
Control Laws ◽  
Model Following ◽  
Novel Approach

The objectives of this paper are to advance dynamic inversion (DI) and explicit model following (EMF) flight control laws for quadrotor unmanned aerial systems (UAS) and to develop an efficient strategy to compute the stability and performance robustness statistics of such control laws given parametric model uncertainty. For this purpose, a parametric model of a quadrotor is identified from flight-test data. The identified model is validated both in frequency and time domains. Next, DI and EMF flight control laws are designed for both inner attitude and outer velocity loops. Finally, a novel approach based on an unscented transform is used to evaluate the statistics of the controller's performance based on the statistics of the uncertain model parameters.

Stalling transport aircraft

2013 ◽  
Vol 117 (1198) ◽  
pp. 1183-1206 ◽  
Author(s):  
P. J. Bolds-Moorehead ◽  
V. G. Chaney ◽  
T. Lutz ◽  
S. Vaux
Keyword(s):  
Wind Tunnel ◽  
Flight Control ◽  
Flight Test ◽  
High Angle ◽  
Flight Testing ◽  
Control Laws ◽  
Transport Aircraft ◽  
Wind Tunnel Data ◽  
Predictive Validation ◽  
Flight Deck

Abstract Airbus and Boeing are cooperatively presenting this topic dealing with transport aircraft stalls. The paper will begin by defining a stall, followed by a review of requirements, predictive validation and flight testing. There are various ways of designing modern jet transports for the stall regime such as aerodynamic approaches, flight deck indications, and augmentation control laws to deal with the high angle-of-attack (α) arena. The goal of augmented control laws for high α is common – no full aerodynamic stall or loss of climb performance should occur in the operational flight envelope, in Normal flight control modes. The validation techniques employed in preparation for a flight test campaign will follow. These include flight characteristic predictions based on wind-tunnel data as well as pilot-in-the-loop simulation rehearsals. The preparation for flight testing will be reviewed from both the engineer and pilot viewpoints. This will be followed by a review of various flight testing that has been conducted. The paper will close with a brief foray into what the future of transport stalls could be – perhaps protection features in degraded flight control modes? What are the benefits as well as drawbacks to increased augmentation for high α?

scholarly journals Inflight investigation of the effects of rotor state measurement and feedback on variable stability helicopters

2021 ◽  
Author(s):  
Marc David Alexander
Keyword(s):  
Flight Control ◽  
National Research Council ◽  
Likelihood Estimation ◽  
Flight Test ◽  
Flight Simulation ◽  
Tracking Accuracy ◽  
Response Dynamics ◽  
Control Laws ◽  
Systems Research ◽  
Model Following Control

This thesis describes a flight test evaluation of flight control laws applying rotor state measurements and feedback on the National Research Council Bell 412 Advanced Systems Research Aircraft (ASRA) and Bell 205A Airborne Simulator (AS). Parameter estimation of a higher-order mathematical model of the ASRA rotor dynamics was achieved by Maximum Likelihood Estimation (MLE) employing coupled rotor-body equations parameterized by explicit rotor and fuselage state measurements. Root Locus (RLM), Classical Multivariable (CMC), Eigenstructure Assignment (EAC), and Model Following control algorithms were implemented in Matlab/Simulink simulation for analysis of coupled rotor-body dynamics. Rotorcraft performance specifications were based on compliance with ADS-33E-PRF and Cooper Harper military handling qualities. Evaluated in desk-top and in-flight simulation, rotor state feedback of longitudinal and lateral disc tilt dynamics by modern multivariable control significantly improves inter-axis decoupling, disturbance rejection characteristics, rotor response dynamics, command tracking accuracy, and rigid-body bandwidth performance.

scholarly journals Inflight investigation of the effects of rotor state measurement and feedback on variable stability helicopters

2021 ◽  
Author(s):  
Marc David Alexander
Keyword(s):  
Flight Control ◽  
National Research Council ◽  
Likelihood Estimation ◽  
Flight Test ◽  
Flight Simulation ◽  
Tracking Accuracy ◽  
Response Dynamics ◽  
Control Laws ◽  
Systems Research ◽  
Model Following Control

This thesis describes a flight test evaluation of flight control laws applying rotor state measurements and feedback on the National Research Council Bell 412 Advanced Systems Research Aircraft (ASRA) and Bell 205A Airborne Simulator (AS). Parameter estimation of a higher-order mathematical model of the ASRA rotor dynamics was achieved by Maximum Likelihood Estimation (MLE) employing coupled rotor-body equations parameterized by explicit rotor and fuselage state measurements. Root Locus (RLM), Classical Multivariable (CMC), Eigenstructure Assignment (EAC), and Model Following control algorithms were implemented in Matlab/Simulink simulation for analysis of coupled rotor-body dynamics. Rotorcraft performance specifications were based on compliance with ADS-33E-PRF and Cooper Harper military handling qualities. Evaluated in desk-top and in-flight simulation, rotor state feedback of longitudinal and lateral disc tilt dynamics by modern multivariable control significantly improves inter-axis decoupling, disturbance rejection characteristics, rotor response dynamics, command tracking accuracy, and rigid-body bandwidth performance.

Research of Robust Flight Control Algorithm for Quadrotor UAV

2014 ◽  
Vol 701-702 ◽  
pp. 743-747 ◽  
Author(s):  
Yun Dou Hu ◽  
Feng Fa Yue ◽  
Dan Dan Hu ◽  
Qing Ji Gao
Keyword(s):  
Robust Control ◽  
Flight Control ◽  
Flight Test ◽  
Loop Control ◽  
Control Approach ◽  
Quadrotor Uav ◽  
Nonlinear Control Problems ◽  
Backstepping Controller ◽  
Robust Flight Control ◽  
Nested Loop

For quadrotor unmanned air vehicles (UAVs) nonlinear control problems under disturbance conditions, a nested loop control approach is presented to realize robust control. The robust control approach is proposed to solve the stabilization and navigation problems in the quadrotor. The robust control strategy is composed of two controllers. A nonlinear backstepping controller is designed for the inner loop to stabilize the attitude angle. A PID controller based on BP neural network is designed for the outer loop in order to generate the reference path for the inner loop. Numerous simulations and flight test experiments have been made to study the performance of controller based on the independently developed quadrotor UAV. The results illustrate that the proposed controller has good stability, maneuverability and robustness.

Design and flight test of active flutter suppression on the X-56A multi-utility technology test-bed aircraft

2016 ◽  
Vol 120 (1228) ◽  
pp. 893-909 ◽  
Author(s):  
E. L. Burnett ◽  
J. A. Beranek ◽  
B. T. Holm-Hansen ◽  
C. J. Atkinson ◽  
P. M. Flick
Keyword(s):  
Flight Control ◽  
Flight Test ◽  
Test Bed ◽  
Control Laws ◽  
Control Approach ◽  
Mode Control ◽  
Flying Qualities ◽  
Technical Challenges ◽  
Long Endurance ◽  
Aircraft Configurations

ABSTRACTEfforts to develop the next generation of aircraft with ever-increasing levels of performance – higher, farther, faster, cheaper – face great technical challenges. One of these technical challenges is to reduce structural weight of the aircraft. Another is to look to aircraft configurations that have been unrealizable to date. Both of these paths can lead to a rigid flex coupling phenomenon that can result in anything from poor flying qualities to the loss of an aircraft due to flutter. This has led to a need to develop an integrated flight and aeroelastic control capability where structural dynamics are included in the synthesis of flight control laws. Studies have indicated that the application of an integrated flight and aeroelastic control approach to a SensorCraft high-altitude long-endurance vehicle would provide substantial performance improvement(1,2). Better flying qualities and an expanded flight envelope through multi-flutter mode control are two areas of improvement afforded by integrated flight and aeroelastic control. By itself, multi-flutter mode control transforms the flutter barrier from a point of catastrophic structural failure to a benign region of flight. This paper discusses the history and issues associated with the development of such an integrated flight and aeroelastic control system for the X-56A aircraft.

String Instabilities in Formation Flight: Limitations Due to Integral Constraints

2004 ◽  
Vol 126 (4) ◽  
pp. 873-879 ◽  
Author(s):  
P. Seiler ◽  
A. Pant ◽  
J. K. Hedrick
Keyword(s):  
Flight Control ◽  
Formation Control ◽  
Energy Savings ◽  
Feedback Loops ◽  
Formation Flight ◽  
Control Laws ◽  
Aerodynamic Efficiency ◽  
Preceding Vehicle ◽  
Specific Control ◽  
Theoretical Results

Flying in formation improves aerodynamic efficiency and, consequently, leads to an energy savings. One strategy for formation control is to follow the preceding vehicle. Many researchers have shown through simulation results and analysis of specific control laws that this strategy leads to amplification of disturbances as they propagate through the formation. This effect is known as string instability. In this paper, we show that string instability is due to a fundamental constraint on coupled feedback loops. The tradeoffs imposed by this constraint imply that predecessor following is an inherently poor strategy for formation flight control. Finally, we present two examples that demonstrate the theoretical results.

scholarly journals Gust Mitigation of Micro Air Vehicles Using Passive Articulated Wings

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Adetunji Oduyela ◽  
Nathan Slegers
Keyword(s):  
Experimental Validation ◽  
Micro Air Vehicles ◽  
Flight Test ◽  
Analytical Investigation ◽  
Micro Air Vehicle ◽  
Gust Alleviation ◽  
Air Vehicle ◽  
Lifting Surfaces ◽  
Gust Mitigation ◽  
Air Vehicles

Birds and insects naturally use passive flexing of their wings to augment their stability in uncertain aerodynamic environments. In a similar manner, micro air vehicle designers have been investigating using wing articulation to take advantage of this phenomenon. The result is a class of articulated micro air vehicles where artificial passive joints are designed into the lifting surfaces. In order to analyze how passive articulation affects performance of micro air vehicles in gusty environments, an efficient 8 degree-of-freedom model is developed. Experimental validation of the proposed mathematical model was accomplished using flight test data of an articulated micro air vehicle obtained from a high resolution indoor tracking facility. Analytical investigation of the gust alleviation properties of the articulated micro air vehicle model was carried out using simulations with varying crosswind gust magnitudes. Simulations show that passive articulation in micro air vehicles can increase their robustness to gusts within a range of joint compliance. It is also shown that if articulation joints are made too compliant that gust mitigation performance is degraded when compared to a rigid system.

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