scholarly journals Validation of Aero-Load Estimator for Convair 880 Aircraft Flight Simulator Benchmark with Electro-Hydrostatic Actuators

2021 ◽  
Vol 13 (3) ◽  
pp. 13-27
Author(s):  
Yamina BOUGHARI ◽  
Ruxandra Mihaela BOTEZ ◽  
Amir BANIAMERIAN ◽  
Ehsan SOBHANI TEHRANI ◽  
Armineh GARABEDIAN
Keyword(s):  
Flight Control ◽  
Flight Test ◽  
Flight Simulation ◽  
High Fidelity ◽  
Aerodynamic Coefficient ◽  
Lookup Tables ◽  
Calculation Methodology ◽  
Geometrical Data ◽  
And Control ◽  
Control Surfaces

Simulating an aircraft model using of high fidelity models of subsystems for its primary and secondary flight control actuators requires measuring or estimating aero-load data acting on flight control surfaces. One solution would be to incorporate the data recorded from flight tests, which is a time-consuming and costly process. This paper proposes another solution based on the validation of an aero-loads estimator or on the hinge moments predictor for fully electrical aircraft simulator benchmark. This estimator is based on an aerodynamic coefficient calculation methodology, inspired by Roskam’s method that uses the geometrical data of the wing and control surfaces airfoils. The hinge moment values are found from two-dimensional lookup tables where the deflections of the control surfaces, aircraft altitude, and aircraft angles of attack are the input vectors of the tables; and the resulting hinge moment coefficients are the output vectors. The resulting hinge moment coefficients of the Convair 880 primary flight control surfaces are compared to those of its recorded flight test data; the results from the new software solution were found to be very accurate. Hinge moment lookup tables are integrated in the Convair 880 high fidelity flight simulation benchmark using mathematical models of energy-efficient Electro-Hydrostatic Actuators (EHA). Autopilot controls are designed for the roll, pitch, attitude and yaw damper motions using Proportional Integral (PI) controller scheduled for different flight conditions. Several different aircraft simulation scenarios are evaluated to demonstrate the efficacy and accuracy of the predicted hinge moment results.

Rotorcraft Lateral-Directional Oscillations: The Anatomy of a Nuisance Mode

2021 ◽  
Author(s):  
Dheeraj Agarwal ◽  
Linghai Lu ◽  
Gareth D. Padfield ◽  
Mark D. White ◽  
Neil Cameron
Keyword(s):  
Simulation Model ◽  
Simulation Models ◽  
Flight Test ◽  
Flight Simulation ◽  
Stability And Control ◽  
Systems Research ◽  
Control Derivatives ◽  
Research Aircraft ◽  
Level Of Understanding ◽  
And Control

High-fidelity rotorcraft flight simulation relies on the availability of a quality flight model that further demands a good level of understanding of the complexities arising from aerodynamic couplings and interference effects. One such example is the difficulty in the prediction of the characteristics of the rotorcraft lateral-directional oscillation (LDO) mode in simulation. Achieving an acceptable level of the damping of this mode is a design challenge requiring simulation models with sufficient fidelity that reveal sources of destabilizing effects. This paper is focused on using System Identification to highlight such fidelity issues using Liverpool's FLIGHTLAB Bell 412 simulation model and in-flight LDO measurements from the bare airframe National Research Council's (Canada) Advanced Systems Research Aircraft. The simulation model was renovated to improve the fidelity of the model. The results show a close match between the identified models and flight test for the LDO mode frequency and damping. Comparison of identified stability and control derivatives with those predicted by the simulation model highlight areas of good and poor fidelity.

VECTOR Program Background and Plan

1998 ◽  
Author(s):  
J. Patrick Schondel ◽  
Michael R. Robinson
Keyword(s):  
Flight Control ◽  
System Integration ◽  
Flight Test ◽  
The United States ◽  
Data System ◽  
Demonstration Program ◽  
Thrust Vectoring ◽  
Stability And Control ◽  
Short Takeoff And Landing ◽  
And Control

The U.S. Navy in cooperation with the Ministries of Defense of Germany and Sweden are initiating a 3-year demonstration program in 1998 to evaluate and define the benefits of thrust vectoring beyond those already understood for Close-in-Combat (CiC). The VECTOR (Vectoring ESTOL Control and Tailless Operational Research) program will capitalize on the X-31 airframe and a contractor team that includes Boeing, G.E., DASA, Volvo, and SAAB to demonstrate the following technologies: • AVEN® Nozzle - a G.E. designed vectoring nozzle applicable to the F404 family of engines • Extremely Short Takeoff and Landing (ESTOL) - employ thrust vectoring and precision control for poststall flight in approach to landing and during take off • Reduced Tail/Tailless - rely on thrust vectoring for primary aircraft stability and control • Advanced Air Data System (AADS) - flush air data ports or optical air data system integrated with the control system to handle the extensive angle-of-attack and sideslip envelope. The flight test activity will be conducted in the United States. However, technical development activities will be conducted in all three countries. Germany and Sweden will contribute technical expertise primarily related to flight control and propulsion system integration, respectively.

Understanding the Effect of Rotor-to-Rotor Interference on CH-47D Helicopter Dynamics

2021 ◽  
Author(s):  
Feyyaz Guner ◽  
David G. Miller ◽  
J. V. R. Prasad
Keyword(s):  
Flight Control ◽  
Influence Factors ◽  
Flight Test ◽  
Flight Simulation ◽  
Flight Control System ◽  
Pressure Potential ◽  
Handling Qualities ◽  
Helicopter Flight ◽  
Lateral Inflow ◽  
Lateral Axis

During the development of the Boeing CH-47D helicopter flight simulation model, test pilots reported mismatch between the flight simulator results and flight test data of the hover and low-speed lateral axis handling qualities, especially for the case without the automatic flight control system. In addressing the observed mismatch, the gains of the longitudinal and lateral components of the inflow model were selected to be significantly higher than their theoretical values. In this study, a detailed understanding of the rotor-to-rotor inflow interference is pursued using a recently developed multi-rotor pressure potential superposition inflow model. It is shown that the coupling between the inflow gradients of individual rotors exists in a tandem rotor, which can be approximated by using higher values for the longitudinal and lateral inflow gains of individual rotors. Further, it is shown that the need for empirical tuning of aerodynamic hub moment influence factors can be eliminated by properly accounting for the rotor-to-rotor interference in the inflow model.

Integrated distributed formation flight control with aerodynamic constraints on attitude and control surfaces

2018 ◽  
Vol 91 (4) ◽  
pp. 2331-2345 ◽  
Author(s):  
Xueyuan Wang ◽  
Hao Fang ◽  
Lihua Dou ◽  
Bin Xin ◽  
Jie Chen
Keyword(s):  
Flight Control ◽  
Formation Flight ◽  
And Control ◽  
Control Surfaces

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.

New methodology and code for Hawker 800XP aircraft stability derivatives calculation from geometrical data

2010 ◽  
Vol 114 (1156) ◽  
pp. 367-376 ◽  
Author(s):  
N. Anton ◽  
R. M. Botez ◽  
D. Popescu
Keyword(s):  
Classical Method ◽  
Complex Structure ◽  
Flight Test ◽  
Stability And Control ◽  
Stability Derivatives ◽  
Subsonic Regime ◽  
Geometrical Data ◽  
And Control ◽  
Derivatives Of ◽  
New Algorithms

Abstract The new FDerivatives code was conceived and developed for calculating static and dynamic stability derivatives of an aircraft in the subsonic regime, based on its geometrical data. The code is robust and it uses geometries and flight conditions to calculate the aircraft’s stability derivatives. FDerivatives contains new algorithms and methods that have been added to DATCOM’s classical method, presented in a USAF Stability and Control DATCOM reference. The new code was written using MATLAB and has a complex structure which contains a graphical interface to facilitate the work of potential users. Results obtained with the new code were evaluated and validated with flight test data provided by CAE Inc. for the Hawker 800XP business aircraft.

scholarly journals Lateral Control Implementation for an Unmanned Aerial Vehicle

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
R. Samar ◽  
M. Zamurad Shah ◽  
M. Nzar
Keyword(s):  
Flight Control ◽  
Flight Test ◽  
Practical Method ◽  
Roll Angle ◽  
Test Results ◽  
Guidance And Control ◽  
Yaw Rate ◽  
Guidance Law ◽  
Aerial Vehicle ◽  
And Control

This paper presents practical aspects of guidance and control design for UAV and its flight test results. The paper focuses on the lateral-directional control and guidance aspects. An introduction to the mission and guidance problem is given first. Waypoints for straight and turning flight paths are defined. Computation of various flight path parameters is discussed, including formulae for real-time calculation of down-range (distance travelled along the desired track), cross-track deviation, and heading error of the vehicle; these are then used in the lateral guidance algorithm. The same section also describes how to make various mission-related decisions online during flight, such as when to start turning and when a waypoint is achieved. The lateral guidance law is then presented, followed by the design of a robust multivariable H∞ controller for roll control and stability augmentation. The controller uses the ailerons and rudder for control of roll angle and stabilization of yaw rate of the vehicle. The reference roll angle is generated by the nonlinear guidance law. The sensors available on-board the vehicle do not measure yaw rate; hence, a practical method of its estimation is proposed. The entire guidance and control scheme is implemented on the flight control computer of the actual aerial vehicle and taken to flight. Flight test results for different mission profiles are presented and discussed.

scholarly journals Method for designing multi-input system identification signals using a compact time-frequency representation

2021 ◽  
Author(s):  
Mathias Stefan Roeser ◽  
Nicolas Fezans
Keyword(s):  
System Identification ◽  
Design Method ◽  
Flight Test ◽  
Compact Representation ◽  
Time Frequency ◽  
Stability And Control ◽  
Frequency Representation ◽  
Aerodynamic Parameters ◽  
Definition Of ◽  
And Control

AbstractA flight test campaign for system identification is a costly and time-consuming task. Models derived from wind tunnel experiments and CFD calculations must be validated and/or updated with flight data to match the real aircraft stability and control characteristics. Classical maneuvers for system identification are mostly one-surface-at-a-time inputs and need to be performed several times at each flight condition. Various methods for defining very rich multi-axis maneuvers, for instance based on multisine/sum of sines signals, already exist. A new design method based on the wavelet transform allowing the definition of multi-axis inputs in the time-frequency domain has been developed. The compact representation chosen allows the user to define fairly complex maneuvers with very few parameters. This method is demonstrated using simulated flight test data from a high-quality Airbus A320 dynamic model. System identification is then performed with this data, and the results show that aerodynamic parameters can still be accurately estimated from these fairly simple multi-axis maneuvers.

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