scholarly journals A multi-channel $$\varvec{H}_\infty $$ preview control approach to load alleviation design for flexible aircraft

2021 ◽  
Author(s):  
Ahmed Khalil ◽  
Nicolas Fezans
Keyword(s):  
Design Methodology ◽  
Control Design ◽  
Doppler Lidar ◽  
Preview Control ◽  
Reduced Order ◽  
Control Approach ◽  
Structural Fatigue ◽  
Trade Offs ◽  
Gust Load Alleviation ◽  
Near Future

AbstractGust load alleviation functions are mainly designed for two objectives: first, alleviating the structural loads resulting from turbulence or gust encounter, and hence reducing the structural fatigue and/or weight; and second, enhancing the ride qualities, and hence the passengers’ comfort. Whilst load alleviation functions can improve both aspects, the designer will still need to make design trade-offs between these two objectives and also between various types and locations of the structural loads. The possible emergence of affordable and reliable remote wind sensor techniques (e.g., Doppler LIDAR) in the future leads to considering new types of load alleviation functions as these sensors would permit anticipating the near future gusts and other types of turbulence. In this paper, we propose a preview control design methodology for the design of a load alleviation function with such anticipation capabilities, based on recent advancements on discrete-time reduced-order multi-channel $$H_\infty $$ H ∞ techniques. The methodology is illustrated on the DLR Discus-2c flexible sailplane model.

scholarly journals Gust load alleviation for flexible aircraft using discrete-time preview control

2020 ◽  
Vol 125 (1284) ◽  
pp. 341-364
Author(s):  
A. Khalil ◽  
N. Fezans
Keyword(s):  
Optimal Control ◽  
Discrete Time ◽  
Wind Profile ◽  
Problem Formulation ◽  
Preview Control ◽  
Control Techniques ◽  
Design Flexibility ◽  
Trade Offs ◽  
Gust Load Alleviation ◽  
Large Aircraft

AbstractTurbulence and gusts cause variations in the aerodynamic forces and moments applied to the structure of aircraft, resulting in passenger discomfort and dynamic loads on the structure that it must be designed to support. By designing Gust Load Alleviation (GLA) systems, two objectives can be achieved: first, realizing higher passenger comfort; and second, reducing the dynamic structural loads, which allows the design of lighter structures. In this paper, a methodology for designing combined feedback/feedforward GLA systems is proposed. The methodology relies on the availability of a wind profile ahead of the aircraft measured by a Doppler LIDAR sensor, and is based on $H_{\infty}$-optimal control techniques and a discrete-time preview-control problem formulation. Moreover, to allow design trade-offs between those two objectives (to achieve design flexibility) as well as to allow specification of robustness criteria, a variant of the problem using multi-channel $H_{\infty}$-optimal control techniques is introduced. The methodology developed in this paper is intended to be applied to large aircraft, e.g. transport aircraft or business jets. The simulation results show the effectiveness of the proposed design methodology in accounting for the measured wind profile to achieve the two mentioned objectives, while ensuring both design flexibility and controller robustness and optimality.

Control-design methodology for drinking-water treatment processes

2010 ◽  
Vol 10 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Kim van Schagen ◽  
Luuk Rietveld ◽  
Alex Veersma ◽  
Robert Babuška
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Design Methodology ◽  
Treatment Plant ◽  
Control Design ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Process Characteristics ◽  
Chemical Usage ◽  
Treatment Step

The performance of a drinking-water treatment plant is determined by the control of the plant. To design the appropriate control system, a control-design methodology of five design steps is proposed, which takes the treatment process characteristics into account. For each design step, the necessary actions are defined. Using the methodology for the pellet-softening treatment step, a new control scheme for the pellet-softening treatment step has been designed and implemented in the full-scale plant. The implementation resulted in a chemical usage reduction of 15% and reduction in the maintenance effort for this treatment step. Corrective actions of operators are no longer necessary.

The CRONE Suspension: Modelling and Stability Analysis

2003 ◽  
Author(s):  
Xavier Moreau ◽  
Olivier Altet ◽  
Alain Oustaloup
Keyword(s):  
Stability Analysis ◽  
Transfer Function ◽  
Design Methodology ◽  
Control Design ◽  
Internal Stability ◽  
Function Modelling ◽  
Robust Control Design ◽  
Force Displacement ◽  
Crone Suspension ◽  
Transfer Function Modelling

The CRONE suspension, French acronym of “suspension a` Comportement Robuste d’Ordre Non Entier”, results from a traditional suspension system whose spring and damper are replaced by a mechanical and hydropneumatic system defined by a fractional (so-called non-integer) order force-displacement transfer function. Modelling, frequency-domain robust control design methodology and internal stability analysis are presented in this paper.

scholarly journals Restauración paisajística de Cantera Rosales. Hellín (Albacete, España)

REVISTARQUIS ◽  
2016 ◽  
Vol 5 (2) ◽  
Author(s):  
José Durán Fernández ◽  
Daniel Moreno Ruiz
Keyword(s):  
Design Methodology ◽  
Mining Activity ◽  
Land Art ◽  
Innovative Design ◽  
Ornamental Stone ◽  
Geometric Reconstruction ◽  
Man And Nature ◽  
The Impact ◽  
Near Future ◽  
The Relationship

ResumenEl texto describe y dibuja una estrategia de recuperación ecológica de una explotación minera de piedra ornamental en activo, situada en el entorno del parque arqueológico del Tolmo de Minateda, en el Término municipal de Hellín (Albacete, España). En el año 2015, la empresa Areniscas Rosal, propietaria de los derechos de explotación de dicha cantera, encargó a la oficina de Arquitectura y Urbanismo SSS (Spanish Studio of Space) un Plan de Restauración para establecer las directrices básicas de una recuperación paisajística que revierta el impacto de la actividad extractiva en un futuro próximo. El proyecto, fundamentado en la filosofía del Land Art, es una reconstrucción geométrica del terreno por medio de la reutilización de los sobrantes de la propia actividad, para así crear un paisaje totalmente nuevo y contemporáneo. El reciclaje, la re-vegetación y una solución proyectual innovadora fundamentan las directrices de esta intervención paisajística y territorial. Las posibilidades de reutilización y disfrute de este nuevo entorno natural podrán ser variadas y enriquecedoras y solo dependerán de una gestión sensible y respetuosa de la relación del hombre con la naturaleza. AbstractThe former document describes and draws a strategy of ecological recovery of an ornamental stone mine in active, located in the archaeological park environment of Tolmo de Minateda in the municipality of Hellín (Albacete, Spain). Back in 2015, the company Rosal Sandstones, which owns the rights to exploit the quarry, commissioned the Office of Architecture and Urbanism SSS (Spanish Studio of Space) a Restoration Plan in order to establish the basic guidelines for a landscape recovery to revert the impact of mining activity in the near future. The project, based on the philosophy of Land Art, is a geometric reconstruction of the ground by means of reusing the leftovers of the activity itself, to thereby create a totally new and contemporary landscape. Recycling, re-vegetation and innovative design methodology solutions substantiate the guidelines of this landscape and territorial intervention. The possibilities for reusability and enjoyment of this new natural environment can be diverse and enriching and, only depend on a sensitive and respectful management of the relationship between man and nature.

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