scholarly journals Required Moment Sets: Enhanced Controllability Analysis for Nonlinear Aircraft Models

2021 ◽  
Vol 11 (8) ◽  
pp. 3456
Author(s):  
Max Söpper ◽  
Jiannan Zhang ◽  
Niclas Bähr ◽  
Florian Holzapfel
Keyword(s):  
Simulation Model ◽  
Flight Control ◽  
Aircraft Design ◽  
Powerful Method ◽  
Specific System ◽  
Nonlinear Simulation ◽  
Critical Moment ◽  
Aircraft Model ◽  
Simulation Based ◽  
Moment Set

Attainable moment sets (AMS) are a powerful method to assess aircraft controllability. However, as attainable moment sets only take into account the achievable moment set of the control effectors, they do not assess the required moment set to fulfill the aircraft mission requirements. This paper proposes to calculate a corresponding required moment set (RMS) which defines a set of moments sufficient for fulfilling aircraft controllability requirements in the mission flight envelope. The paper applies the required moment set approach to a nonlinear simulation model of an electric vertical take off vehicle (eVTOL) transition drone in hover. By comparing the required moment set to the AMS of the aircraft model, moment set margins are derived and used to assess the controllability of the considered aircraft. The results indicate that the combined evaluation directly identifies critical moment channels and margins, which is advantageous when compared to a pure AMS-based evaluation. The proposed approach enables the execution of simulation-based assessments in aircraft design and flight control development. In the early stages of aircraft design, required moment sets can support sizing, positioning and tilting of control effectors (e.g., propulsive elements) to fit the AMS to the actual required force and moment set for the specific system.

Fidelity enhancement of a rotorcraft simulation model through system identification

2011 ◽  
Vol 115 (1170) ◽  
pp. 453-470 ◽  
Author(s):  
L. Lu ◽  
G. D. Padfield ◽  
M. White ◽  
P. Perfect
Keyword(s):  
System Identification ◽  
Simulation Model ◽  
Linear Models ◽  
Aircraft Design ◽  
Design Data ◽  
Loads Analysis ◽  
Physics Based Simulation ◽  
Six Degree Of Freedom ◽  
The University ◽  
Frequency Domain Approach

AbstractHigh fidelity modelling and simulation are prerequisites for ensuring confidence in decision making during aircraft design and development, including performance and handling qualities, control law developments, aircraft dynamic loads analysis, and the creation of a realistic simulation environment. The techniques of system identification provide a systematic framework for ‘enhancing’ a physics–based simulation model derived from first principles and aircraft design data. In this paper we adopt a frequency domain approach for model enhancement and fidelity improvement of a baseline FLIGHTLAB Bell 412 helicopter model developed at the University of Liverpool. Predictability tests are based on responses to multi–step control inputs. The techniques have been used to generate one, three, and six degree-of-freedom linear models, and their derivatives and predictability are compared to evaluate and augment the fidelity of the FLIGHTLAB model. The enhancement process thus involves augmenting the simulation model based on the identified parameters. The results are reported within the context of the rotorcraft simulation fidelity project, Lifting Standards, involving collaboration with the Flight Research Laboratory (NRC, Ottawa), supported with flight testing on the ASRA research helicopter.

UAV Autopilot Design for the AUVSI, UAS International Competition

2009 ◽  
Author(s):  
Muhammad M. Mahmood ◽  
Md S. Chowdhury ◽  
Rizwan Ihsan ◽  
Umar M. Yousaf ◽  
Mohamed W. Afifi ◽  
...  
Keyword(s):  
Undergraduate Students ◽  
Flight Control ◽  
Computer Network ◽  
Imaging System ◽  
Aircraft Design ◽  
Unmanned Aircraft ◽  
American University ◽  
Ground Station ◽  
Aerial Imaging ◽  
Safety Features

This paper provides an overview of the first participation of the design developed by the undergraduate students of American University of Sharjah to meet the requirements laid forth in the 2008 Association for Unmanned Vehicle Systems International (AUVSI) Student UAS competition. The overall objective of the competition is to fly autonomously over a GPS waypoint defined route and also to identify and locate ground based targets within a confined area. To meet the objectives an unmanned aircraft is equipped with autonomous functionality and aerial imaging system. A ground station and supportive software to keep track of the aircraft routine and log the raw data gained from the flight is also designed. Achieving complete success depends upon mission elements which include autonomous take-off and landing, autonomous control and waypoint navigation. The onboard equipment used was a flight control computer network, IMU, GPS, an air data system and a camera. Additionally, safety features such as manual override was also installed. Presented in this report are aircraft design and testing, the processes involved in accomplishing the goal, and the results and achievements.

Level Mobile Shot Blasting Machine Shot Blasting Wheel in the Dynamic Simulation Based on ADAMS

2011 ◽  
Vol 148-149 ◽  
pp. 837-841
Author(s):  
Dan Zhang ◽  
Yuan Lin Liu ◽  
Hong Tao Li
Keyword(s):  
Simulation Model ◽  
Dynamic Simulation ◽  
Mechanical Model ◽  
Shot Blasting ◽  
Air Resistance ◽  
Simulation Based ◽  
Dynamic Simulation Model ◽  
External Forces ◽  
Machine Analysis ◽  
Speed Of Analysis

The level of mobile shot blasting machine analysis, a mechanical model of the projectile with the blade and shot rounds of dynamic simulation model, the model by imposing constraints and external forces, analysis of air resistance, friction, blade length and projectile diameter of throw playing speed. Played by the speed of analysis can throw further analysis of various parameters on the effect of throwing fight.

Integrated Aircraft Modeling Research for Accurate Flight Control System Design

2013 ◽  
Vol 791-793 ◽  
pp. 658-662
Author(s):  
Chao Zhang ◽  
Yi Nan Liu ◽  
Jian Hui Xu
Keyword(s):  
Control System ◽  
System Design ◽  
Flight Control ◽  
Time Delays ◽  
Flight Dynamics ◽  
Control System Design ◽  
Control Law ◽  
Flight Control System ◽  
Aircraft Model ◽  
Simulation Results

In order to realize accurate flight control system design and simulation, an integrated scheme of aircraft model which consists of flight dynamics, fly-by-wire (FBW) platform and flight environment is proposed. Flight environment includes gravity, wind, and atmosphere. And the actuator and sensors such as gyroscope and accelerometer models are considered in the FBW platform. All parts of the integrated model are closely connected and interacted with each other. Simulation results confirm the effectiveness of the integrated aircraft model and also indicate that the (Flight Control Law) FCL must be designed with robustness to sensor noise and time delays with the FBW platform in addition to the required robustness to model uncertainty in flight dynamics.

Application of Agile Model-Based Systems Engineering in aircraft conceptual design

2019 ◽  
Vol 123 (1268) ◽  
pp. 1561-1601 ◽  
Author(s):  
G. P. Krupa
Keyword(s):  
Systems Engineering ◽  
Flight Control ◽  
System Analysis ◽  
Object Oriented ◽  
Aircraft Design ◽  
System Engineering ◽  
Smooth Transition ◽  
Model Based ◽  
Agile Model ◽  
Aircraft Conceptual Design

ABSTRACTOne of the challenges of modern engineering design is the amount of data that designers must keep track while performing system analysis and synthesis. This task is particularly important in the design process of complex systems such as novel aerospace systems where Modeling and Simulation play an essential role. The Agile philosophy stems from the field of Software Engineering and describes an approach to development in which requirements and solutions gradually develop through collaboration between self-organising cross-functional teams and end users. Agile Model-Based System Engineering (AMBSE) is the application of the Agile philosophy to Model-Based System Engineering. In this paper, AMBSE is accomplished through the application of the Object-Oriented System Engineering Method (OOSEM). OOSEM employs a top-down scenario-driven process that adopts System Modeling Language (SysML) and leverages the object-oriented paradigm to support the analysis, specification, design, and verification of systems. AMBSE assisted by mathematical modelling and safety assessment techniques is applied to the first design iterations of the main aircraft systems, allowing a comprehensive design exploration. The flight control system was chosen to illustrate the procedure in detail, emphasising the synthesis of a six-degrees-of-freedom model augmented by dynamic inversion control for a hypothetical supersonic transport aircraft satisfying class II MIL-F-8785C handling qualities. It is concluded that AMBSE presents promising properties to support future aircraft development within the current regulatory framework for aircraft design, while enabling a smooth transition from conceptual to preliminary design.

scholarly journals Flight Control Design for a Tailless Aircraft Using Eigenstructure Assignment

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Clara Nieto-Wire ◽  
Kenneth Sobel
Keyword(s):  
Control System ◽  
Flight Control ◽  
Eigenstructure Assignment ◽  
Flight Control System ◽  
Nonlinear Simulation ◽  
Thrust Vectoring ◽  
Stability Margins ◽  
Gain Margin ◽  
Command Systems ◽  
Tailless Aircraft

We apply eigenstructure assignment to the design of a flight control system for a wind tunnel model of a tailless aircraft. The aircraft, known as the innovative control effectors (ICEs) aircraft, has unconventional control surfaces plus pitch and yaw thrust vectoring. We linearize the aircraft in straight and level flight at an altitude of 15,000 feet and Mach number 0.4. Then, we separately design flight control systems for the longitudinal and lateral dynamics. We use a control allocation scheme with weights so that the lateral pseudoinputs are yaw and roll moment, and the longitudinal pseudoinput is pitching moment. In contrast to previous eigenstructure assignment designs for the ICE aircraft, we consider the phugoid mode, thrust vectoring, and stability margins. We show how to simultaneously stabilize the phugoid mode, satisfy MIL-F-8785C mode specifications, and satisfy MIL-F-9490D phase and gain margin specifications. We also use a cstar command system that is preferable to earlier pitch-rate command systems. Finally, we present simulation results of the combined longitudinal/lateral flight control system using a full 6DOF nonlinear simulation with approximately 20,000 values for the aerodynamic coefficients. Our simulation includes limiters on actuator deflections, deflection rates, and control system integrators.

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