scholarly journals A trim problem formulation for maximum control authority using the Attainable Moment Set geometry

2021 ◽  
Author(s):  
Carmine Varriale ◽  
Mark Voskuijl
Keyword(s):  
Inequality Constraints ◽  
Problem Formulation ◽  
Control Surface ◽  
Control Effort ◽  
Decision Variables ◽  
Control Authority ◽  
Control Forces ◽  
Lift Control ◽  
Moment Set ◽  
Control Surfaces

AbstractThis paper presents a generic trim problem formulation, in the form of a constrained optimization problem, which employs forces and moments due to the aircraft control surfaces as decision variables. The geometry of the Attainable Moment Set (AMS), i.e. the set of all control forces and moments attainable by the control surfaces, is used to define linear equality and inequality constraints for the control forces decision variables. Trim control forces and moments are mapped to control surface deflections at every solver iteration through a linear programming formulation of the direct Control Allocation algorithm. The methodology is applied to an innovative box-wing aircraft configuration with redundant control surfaces, which can partially decouple lift and pitch control, and allow direct lift control. Novel trim applications are presented to maximize control authority about the lift and pitch axes, and a “balanced” control authority. The latter can be intended as equivalent to the classic concept of minimum control effort. Control authority is defined on the basis of control forces and moments, and interpreted geometrically as a distance within the AMS. Results show that the method is able to capitalize on the angle of attack or the throttle setting to obtain the control surfaces deflections which maximize control authority in the assigned direction. More conventional trim applications for minimum total drag and for assigned angle of elevation are also explored.

Application of Pulsed Blowing Technique in High-Lift Control Surface Design

2012 ◽  
Vol 482-484 ◽  
pp. 121-125
Author(s):  
Peng Wu ◽  
Xue Ying Deng ◽  
Yan Kui Wang
Keyword(s):  
Flow Separation ◽  
Deflection Angle ◽  
Leading Edge ◽  
Control Surface ◽  
Control Technique ◽  
High Lift ◽  
Surface Design ◽  
Aerodynamic Efficiency ◽  
Lift Control ◽  
Control Surfaces

Because the flight performance of aircraft is so dependent on aerodynamic efficiency of control surfaces, it is very important to eliminate the flow separation over the control surfaces at high deflection angle in order to keep the aircraft having good flight capability, especially for the modern aircraft with tailless aerodynamic configuration. A novel flow control technique to eliminate flow separation of control surface at high deflection angle and creat high lift increment by pulsed blowing at leading edge of control surface is discussed in this paper. The performance of lift enhancment of control surface which used this technique is investigated, and based on the zonal analysis of pulsed frequency, the control characteristic of this technique is also discussed.

scholarly journals Trim for Maximum Control Authority using the Attainable Moment Set

2020 ◽  
Author(s):  
Carmine Varriale ◽  
Mark Voskuijl ◽  
Leo L. Veldhuis
Keyword(s):  
Control Authority ◽  
Moment Set

Combined Analysis and Optimization of Extended Heat Transfer Surfaces

1985 ◽  
Vol 107 (3) ◽  
pp. 527-532 ◽  
Author(s):  
A. N. Hrymak ◽  
G. J. McRae ◽  
A. W. Westerberg
Keyword(s):  
Optimization Problem ◽  
Radiative Heat ◽  
Inequality Constraints ◽  
Finite Element Approximation ◽  
Problem Formulation ◽  
Element Approximation ◽  
Problem Solution ◽  
Radiative Heat Loss ◽  
Equality And Inequality Constraints ◽  
Grid Points

This study presents an efficient numerical method to discover the optimal shape for a fin subject to both convective and radiative heat loss. Problem formulation is a finite element approximation to the conduction equation embedded within and solved simultaneously with the shape optimization problem. The approach handles arbitrary equality and inequality constraints. Grid points move to conform to the fin shape during the problem solution, reducing the number of elements required in the solution.

Transient Response Study on Rolling Effectiveness of Multiple Control Surfaces

2002 ◽  
Author(s):  
Deman Tang ◽  
Aiqin Li ◽  
Earl H. Dowell
Keyword(s):  
Transient Response ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Control Surface ◽  
Multiple Control ◽  
Wing Model ◽  
Aerodynamic Model ◽  
Control Surfaces ◽  
Dry Friction Damping

In the present paper, a transient response study of the effectiveness of trailing and leading edge control surfaces has been made for a rolling wing-fuselage model. An experimental model and wind tunnel test are used to assess the theoretical results. The theoretical model includes the inherently nonlinear dry friction damping moment that is present between the spindle support and the experimental aeroelastic wing model. The roll trim equation of motion and the appropriate aeroelastic equations are solved for different combinations of leading and trailing edge control surface rotations using a reduced order aerodynamic model based upon the fluid eigenmodes of three dimensional vortex lattice aerodynamic theory. The present paper provides new insights into the transient dynamic behavior and design of an adaptive aeroelastic wing using trailing and leading edge control surfaces.

scholarly journals Airfoil Selection Procedure, Wind Tunnel Experimentation and Implementation of 6DOF Modeling on a Flying Wing Micro Aerial Vehicle

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 553 ◽  
Author(s):  
Taimur Ali Shams ◽  
Syed Irtiza Ali Shah ◽  
Ali Javed ◽  
Syed Hossein Raza Hamdani
Keyword(s):  
Wind Tunnel ◽  
Equations Of Motion ◽  
Selection Procedure ◽  
Leading Edge ◽  
Control Surface ◽  
Flight Tests ◽  
Micro Aerial Vehicle ◽  
Aerial Vehicle ◽  
P Factor ◽  
Control Surfaces

Airfoil selection procedure, wind tunnel testing and an implementation of 6-DOF model on flying wing micro aerial vehicle (FWMAV) has been proposed in this research. The selection procedure of airfoil has been developed by considering parameters related to aerodynamic efficiency and flight stability. Airfoil aerodynamic parameters have been calculated using a potential flow solver for ten candidate airfoils. Eppler-387 proved to be the most efficient reflexed airfoil and therefore was selected for fabrication and further flight testing of vehicle. Elevon control surfaces have been designed and evaluated for longitudinal and lateral control. The vehicle was fabricated using hot wire machine with EPP styrofoam of density 50 Kg/ m 3 . Static aerodynamic coefficients were evaluated using wind tunnel tests conducted at cruise velocity of 20 m/s for varying angles of attack. Rate derivatives and elevon control derivatives have also been calculated. Equations of motion for FWMAV have been written in a body axis system yielding a 6-DOF model. It was found during flight tests that vehicle conducted coordinated turns with no appreciable adverse yaw. Since FWMAV was not designed with a vertical stabilizer and rudder control surface, directional stability was therefore augmented through winglets and high wing leading edge sweep. Major problems encountered during flight tests were related to left rolling tendency. The left roll tendency was found inherent to clockwise rotating propeller as ‘P’ factor, gyroscopic precession, torque effect and spiraling slipstream. To achieve successful flights, many actions were required including removal of excessive play from elevon control rods, active actuation of control surfaces, enhanced launch speed during take off, and increased throttle control during initial phase of flight. FWMAV flew many successful stable flights in which intended mission profile was accomplished, thereby validating the proposed airfoil selection procedure, modeling technique and proposed design.

Use of Multiple SMA Wires for Morphing of Inflatable Wings

2010 ◽  
Author(s):  
Anthony D. McDonald ◽  
Scott J. I. Walker
Keyword(s):  
Flight Control ◽  
Control Method ◽  
Control Surface ◽  
Static Testing ◽  
Wing Model ◽  
Additional Control ◽  
Pulling Force ◽  
Wing Morphing ◽  
The University ◽  
Control Surfaces

The concept of inflatable wings has design heritage and they have recently seen renewed interest, largely due to the increased demand in unmanned aerial vehicles (UAVs). They offer design advantages over conventional wings, particularly with regard to stowage and portability, since they can be tightly packed when undeployed. Unfortunately current methods of flight control involve the use of additional control surfaces attached to the trailing edge of the wing, adversely affecting the stowage capabilities. One way of overcoming this restriction is to use the wing itself as a control surface, by morphing the very shape of the wing to achieve the desired results. This article outlines the research performed at the University of Southampton into differing configurations of Shape Memory Alloy (SMA) wires as a controllable actuator for the wing morphing. Specifically the use of multiple wires to further enhance this control was the focus of this work. A simple test rig was constructed in order to evaluate the pulling force achievable by combinations of SMA wires in a number of configurations. The most promising of these configurations was then attached to an inflatable wing model for further testing. Both static testing and wind tunnel testing was undertaken, evaluating the authority of flight control such a system could achieve. The test results are presented in this paper, giving an initial performance assessment of the proposed control method.

Novel Silicon Based Anodic Spark Deposition Treatment for Dental Implant

2008 ◽  
Vol 47-50 ◽  
pp. 1434-1437
Author(s):  
Lertrit Sarinnaphakorn ◽  
Patrick Mesquida ◽  
Roberto Chiesa ◽  
C. Giordano ◽  
Michael Fenlon ◽  
...  
Keyword(s):  
Pure Titanium ◽  
Biological Response ◽  
Titanium Implants ◽  
Control Surface ◽  
Commercially Pure Titanium ◽  
Titanium Surfaces ◽  
Silicon Based ◽  
And Control ◽  
Control Surfaces

Surface treated titanium implants are increasingly being used in dental and orthopaedic applications. This study examined the biological response of primary human alveolar osteoblast (aHOB) cells to a novel silicon based anodic spark deposition treated titanium surfaces. Three different titanium surfaces were investigated: anodic spark deposition (ASD) with silicon based (ASDSi), BioSpark™ (BS), and chemically etched (BioRough™, BR). Commercially pure titanium (cpTi) was the non-treated control surface. Physiological and biological evaluations were conducted on all test and control surfaces. Surface scanning (SEM, EDS, and AFM) confirmed a nano-topography, which was textured for all surfaces; and similar surface chemical composition (Ca and P), of significant was the Si peak on the ASDSi surface. Cell morphological study (SEM) showed good adhere and spreading over the surface, with metabolically active cells having extended filopodia. Biological response was observed with cell proliferation on all test surfaces for the period studied. Proliferation rate was seen to increase with time. This initial favourable cell response will be of benefit in the long term osseointegration of the implant surfaces.

Predicting the Radiated Noise of a Submarine Propeller with Different Types of Control Surfaces

2021 ◽  
pp. 1-14
Author(s):  
Jui-Hsiang Kao ◽  
Shang-Sheng Chin ◽  
Fang-Nan Chang ◽  
Yu-Han Tsai ◽  
Hua-Tung Wu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Wave Theory ◽  
Control Surface ◽  
Linear Wave ◽  
Dipole Strength ◽  
Unsteady Forces ◽  
Radiated Noise ◽  
Wake Field ◽  
Diving Depth ◽  
Control Surfaces

The objective of this paper is to predict the noise radiated from submarine propellers with different control surface types (the cross- and X-type). When the propellers are free from cavitation, such as those of submarines at a diving depth, the radiated noise dominate, due to unsteady propeller forces. A well-known submarine model (DARPA SUBOFF) is taken as the computing sample. Simulations for hydrodynamics, including stern wakes and unsteady propeller forces, are carried out by using CFD (Computational Fluid Dynamics) technology, and the results are compared with the experimental data. The accuracy of the predicted noise depends on the CFD results. Comparisons between the CFD results and the experimental data are in good agreement. The CFD results are treated as dipole strengths in the linear wave theory to predict the radiated noise caused by the unsteady forces of the propeller. It is found that, when the control surface is of the X-type, the propeller inflow is more uniform, and the radiated noise can be decreased by about 5 dB compared to the cruciform control surface. Introduction When submarines are at diving depth, the noise generated by unsteady propeller forces (i.e., dipole strengths) will dominate. Because the juncture vortex caused by the sail makes the propeller inflow more nonuniform, the dipole strength will be enhanced and the radiated noise will be more noticeable. The uniformity of the wake field at the stern should be controlled well in order to restrain the radiated noise.

On the feasibility of constrained linear control problems with application to the ALSTOM gasifier

2005 ◽  
Vol 219 (3) ◽  
pp. 207-213 ◽  
Author(s):  
I K Kookos
Keyword(s):  
Problem Formulation ◽  
Control Law ◽  
Control Problems ◽  
Satisfactory Solution ◽  
Control Effort ◽  
Control Community ◽  
Academic Control ◽  
And Control ◽  
Process Constraints

In 1997 the ALSTOM Power Technology Centre issued an open challenge to the academic control community, which addressed the control of a gasifier plant at three different production levels. Despite the numerous attempts and control methodologies that have been applied to the ALSTOM benchmark case study no satisfactory solution has yet been presented. This work aims to study the feasibility of the gasifier control problem. It is shown that the problem formulation corresponds to an infeasible problem. More specifically, operation at nominal conditions (100 per cent load) is shown to be easy and minimum control effort is required to satisfy process specifications. Operation, on the other hand, at the 0 per cent load conditions is infeasible and as a result no control law can be found that satisfies all process constraints. In the light of the findings of this study it is recommended that the ALSTOM benchmark gasifier problem should be modified to alleviate the infeasibility problem.

Multi-Speed Gearbox Design Using Multi-Objective Evolutionary Algorithms

2003 ◽  
Vol 125 (3) ◽  
pp. 609-619 ◽  
Author(s):  
Kalyanmoy Deb ◽  
Sachin Jain
Keyword(s):  
Original Problem ◽  
Problem Formulation ◽  
Optimization Techniques ◽  
Nsga Ii ◽  
Nondominated Solutions ◽  
Multi Objective ◽  
Decision Variables ◽  
Mathematical Expressions ◽  
Different Types ◽  
Important Design

Optimal design of a multi-speed gearbox involves different types of decision variables and objectives. Due to lack of efficient classical optimization techniques, such problems are usually decomposed into tractable subproblems and solved. Moreover, in most cases the explicit mathematical expressions of the problem formulation is exploited to arrive at the optimal solutions. In this paper, we demonstrate the use of a multi-objective evolutionary algorithm, which is capable of solving the original problem involving mixed discrete and real-valued parameters and more than one objectives, and is capable of finding multiple nondominated solutions in a single simulation run. On a number of instantiations of the gearbox design problem having different complexities, the efficacy of NSGA-II in handling different types of decision variables, constraints, and multiple objectives are demonstrated. A highlight of the suggested procedure is that a post-optimal investigation of the obtained solutions allows a designer to discover important design principles which are otherwise difficult to obtain using other means.

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