Andrei Popov | École de Technologie Supérieure (original) (raw)

Papers by Andrei Popov

nt.ntnu.no

This article presents an identification technique for distributed systems with identical units us... more This article presents an identification technique for distributed systems with identical units using linear recurrent neural networks and exploiting the replicated structure of the units inside the system. The proposed method is applicable both to open-loop and closed-loop identification, takes into consideration boundary conditions and available information about the structure of the system, and is capable of identifying systems with heterogeneous units. The approach provides parameters estimate with minimum bias for unstable plant models when there is additive colored noise in the data. The method is described for two-dimensional systems (one for time and one for space), but is equally applicable to systems having more dimensions in space. The effectiveness of the method is demonstrated by two examples.

In this paper, main simulation methodology and results for the laminar to turbulent flow transiti... more In this paper, main simulation methodology and results for the laminar to turbulent flow transition controller on a morphing wing equipped with two smart actuators and thirty sensors (optical and Kulite) to be installed and tested in the NRC wind tunnel is presented.

The objective of the research presented here is to develop a new morphing mechanism using smart m... more The objective of the research presented here is to develop a new morphing mechanism using smart materials such as Shape Memory Alloy (SMA) as actuators and fuzzy logic techniques. These smart actuators deform the upper wing surface, made of a flexible skin, so that the laminar-to-turbulent transition point could move close to the wing trailing edge. The ultimate goal of this research project is to obtain a drag reduction as a function of flow condition by changing the wing shape. The transition location detection is based on pressure signals measured by optical and Kulite sensors installed on the upper wing flexible surface. Depending on the project evolution phase, two architectures are considered for the morphing system: open loop and closed loop. The difference between these two architectures is given by the use of the transition point as feedback signal. This research work was a part of a morphing wing project developed by the Ecole de Technologie Supérieure in Montréal, Canada, in collaboration with the Ecole Polytechnique in Montréal and the Institute for Aerospace Research at the National Research Council Canada (IAR-NRC). Recently, morphing wing system studies have branched out into new research directions. Extremely complex and catalogued as inter-and multidisciplinary studies, morphing wing studies continue to 'push' the science, up to the extreme boundaries of mathematics and physics. These multidisciplinary studies therefore require knowledge in the following disciplines: aerodynamics and computational fluid dynamics, aeroelasticity, automatic control, intelligent materials, signal detection using the latest miniaturized sensors, high computer-time calculations, wind tunnel and flight testing, instruments, and signal acquisition-these signals have such speed that they are raising serious problems for the existing calculus technology. Consequently, real-time system functioning is conditioned (in addition to other factors) by the obtaining of the best data processing algorithms, easy to implement software within the command and control unit. Fuzzy logic theories, which offer remarkable facilities, may therefore be used in these algorithms. They facilitate signal processing by allowing empirical models to be designed based on experimental data; and thus, the complex mathematical calculus currently in use can be avoided. In addition, fuzzy logic can be used to model highly non-linear, multidimensional systems, including those with parameter variations, or where the sensors' signals are not accurate enough for other models. This research project included the following: optical sensor selection and testing for laminar-to-turbulent flow transition validation (by use of XFoil code and Matlab), smart material actuator modeling, aeroelasticity wing studies using MSC/Nastran, open loop and closed loop transition delay controller design, integration and validation on a wing equipped with SMAs and optical sensors. A first phase of this project involved the determination of optimized airfoils available for 35 different flow conditions expressed in terms of five Mach numbers and seven angles of attack combinations. The optimized airfoils, derived from a laminar WTEA-TE1 reference airfoil (Fig. 1), were calculated and were used as a starting point in the actuation system design. Two steps were completed in the actuation system design phase: optimization of the number and positions of flexible skin actuation points, establishment of each actuation line's architecture (Fig. 2). The next phase of the project was about the design of the actuation control in open loop architecture of the morphing wing, for which an integrated on-off versus a fuzzy PID architecture was chosen (Fig. 3 to Fig. 5). In this design, numerical simulations of the open loop morphing wing integrated system, based on a SMA non-linear model, were performed; as subsequent validation methods, a bench test (Fig. 6, Fig. 7) and a wind tunnel test were conducted (Fig. 8, Fig. 9). In the final phase a closed loop controller was developed and experimentally validated (Fig. 10-Fig. 13).

Journal of Aircraft, May 22, 2012

In this paper, wind tunnel results of a real time optimization of a morphing wing in wind tunnel ... more In this paper, wind tunnel results of a real time optimization of a morphing wing in wind tunnel for delaying the transition towards the trailing edge are presented. A morphing rectangular finite aspect ratio wing, having a WTEA reference airfoil cross-section, was considered with its upper surface made of a flexible composite material and instrumented with Kulite pressure sensors, and two smart memory alloys actuators. Several wind tunnel tests runs for various Mach numbers, angles of attack and Reynolds numbers were performed in the 6'×9' wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC). Unsteady pressure signals were recorded and used as feed back in real time control while the morphing wing was requested to reproduce various optimized airfoils by changing automatically the two actuators strokes. The paper shows the optimization method implemented into the control software code that allows the morphing wing to adjust its shape to an optimum configuration under the wind tunnel airflow conditions.

In this paper, wind tunnel experiment was performed for boundary layer transition control on a mo... more In this paper, wind tunnel experiment was performed for boundary layer transition control on a morphing wing. Surface pressure fluctuations were measured using Kulite transducers at high sampling rate. A controller, linking the Kulites signals fluctuation to the smart material actuators, is incorporated to the control system, where the signals are analyzed and the transition location is detected. Several wind tunnel test runs for various Mach numbers and angles of attack were performed in the 6 × 9 ft 2 wind tunnel at the Institute for Aerospace Research at the National Research Council Canada. A rectangular finite aspect ratio wing, having a morphing airfoil cross section due to a flexible skin installed on the upper surface of the wing, was instrumented with sixteen Kulite transducers. The Mach number was varied from 0.2 to 0.3 and the angle of attack between-1 o and 2 o. Unsteady pressure signals were recorded and analyzed and a thorough comparison, in terms of mean pressure coefficients and their standard deviations, was performed against theoretical predictions using the XFoil computational fluid dynamics code. The unsteady pressure signals were analyzed through FFT spectral decomposition for detecting the Tollmien-Schlichting waves frequencies that trigger transition. In addition, infra red measurements were performed to asses the performance of the Kulite transducers in detecting the transition location and serve as an additional validation of the XFoil code in predicting the transition location .

ABSTRACT "Master thesis submitted to École de technologie supérieure in partial fulfilme... more ABSTRACT "Master thesis submitted to École de technologie supérieure in partial fulfilment of the requirements for the degree of master of science in engineering". Thèse (M. Ing.)--École de technologie supérieure, Montréal, 2005. Bibliogr.: f. [146]-147. Ch. 1. Literature overview -- Ch. 2. Flight tests -- Ch. 3. Simulation model -- Ch. 4. Model validation -- Ch. 5. Lateral and directional handling quality validation -- Ch. 6. Hover performance validation -- Ch. 7. Autorotation performance validation. Accès réservé aux membres des établissements autorisés.

... andrei-vladimir.popov.1@ens.etsmtl.ca Lucian Grigorie Postdoc fellowship, Laboratory of Resea... more ... andrei-vladimir.popov.1@ens.etsmtl.ca Lucian Grigorie Postdoc fellowship, Laboratory of Research in Active Controls, Avionics and AeroServoElasticity LARCASE 1100 Notre-Dame West Street, Montreal, Quebec, H3C 1K3 Canada ltgrigorie@yahoo.com Ruxandra Mihaela ...

Icinco, 2010

The paper represents the second part of a study related to the development of an actuators contro... more The paper represents the second part of a study related to the development of an actuators control system for a morphing wing application, and describes the experimental validation of the control designed in the first part. After a short presentation of the finally adopted control architecture, the physical implementation of the control is done. To implement the controller on the physical model two Programmable Switching Power Supplies AMREL SPS100-33 and a Quanser Q8 data acquisition card, were used. The inputs of the data acquisition were two signals from Linear Variable Differential Transformer potentiometers, indicating the positions of the actuators, and six signals from thermocouples installed on the SMA wires. The acquisition board outputs channels were used to control power supplies in order to obtain the desired skin deflections. The control validation was made in two experimental ways: bench test and wind tunnel test. All 35 optimized airfoil cases, used in the design phase, were converted into actuators vertical displacements which were used as inputs reference for the controller. In the wind tunnel tests a comparative study was realized around of the transition point position for the reference airfoil and for each optimized airfoil.

Proquest Dissertations and Theses Thesis Ecole De Technologie Superieure 2010 Publication Number Aainr60090 Isbn 9780494600900 Source Dissertation Abstracts International Volume 71 05 Section B Page 3169 262 P, 2010

ABSTRACT The aerospace industry is motivated to reduce fuel consumption in large transport aircra... more ABSTRACT The aerospace industry is motivated to reduce fuel consumption in large transport aircraft, mainly through drag reduction. The main objective of the global project is the development of an active control system of wing airfoil geometry during flight in order to allow drag reduction. Drag reduction on a wing can be achieved through modifications in the laminar-to-turbulent flow transition point position, which should be situated as close as possible to the trailing edge of the airfoil wing. As the transition point plays a crucial part in this project, this work focuses on the control of its position on the airfoil, as an effect of controlling the deflection of a morphing wing airfoil equipped with a flexible skin. The paper presents the modeling and the experimental testing of the aerodynamic performance of a morphing wing, starting from the design concept phase all the way to the bench and wind tunnel tests phases. Several wind tunnel test runs for various Mach numbers and angles of attack were performed in the 6 x 9 ft2 wind tunnel at the Institute for Aerospace Research at the National Research Council Canada. A rectangular finite aspect ratio wing, having a morphing airfoil cross-section due to a flexible skin installed on the upper surface of the wing, was instrumented with Kulite transducers. The Mach number varied from 0.2 to 0.3 and the angle of attack between -1° and 2°. Unsteady pressure signals were recorded and analyzed and a thorough comparison, in terms of mean pressure coefficients and their standard deviations, was performed against theoretical predictions, using the XFoil computational fluid dynamics code. The acquired pressure data was analyzed through custom-made software created with Matlab/Simulink in order to detect the noise magnitude in the surface airflow and to localize the transition point position on the wing upper surface. This signal processing was necessary in order to detect the Tollmien-Schlichting waves responsible for triggering the transition from laminar to turbulent flow. The flexible skin needed to morph its shape through two actuation points in order to obtain an optimized airfoil shape for several flow conditions in the wind tunnel. The two shape memory alloy actuators, having a non-linear behavior, drove the displacement of the two control points of the flexible skin towards the optimized airfoil shape. This thesis presents the methodology used and the results obtained from designing the controller of the two shape memory actuators as well as the methods used for morphing wing control in the wind tunnel tests designed to prove the concept and validity of the system in real time. Keywords: wing, morphing, laminar, turbulent, transition, control, wind tunnel

Icinco, 2010

This chapter presents the design and the validation of the actuators control system for a morphin... more This chapter presents the design and the validation of the actuators control system for a morphing wing application. Some smart materials, like Shape Memory Alloy (SMA), are used as actuators to modify the upper surface of the wing made of a flexible skin. The finally adopted control law is a combination of a bi-positional law and a PI law. The controller is validated in two experimental ways: bench test and wind tunnel test. All optimized airfoil cases, used in the design phase, are converted into actuators vertical displacements which are used as inputs reference for the controller. In the wind tunnel tests a comparative study is realized around of the transition point position for the reference airfoil and for each optimized airfoil.

Journal of Aircraft, 2010

This paper presents the modeling and the experimental testing of the aerodynamic performance of a... more This paper presents the modeling and the experimental testing of the aerodynamic performance of a morphing wing in open-loop architecture. We show the method used to acquire the pressure data from the external surface of the flexible wing skin, using incorporated Kulite pressure sensors and the instrumentation of the morphing controller.

In this paper, wind tunnel experiment was performed for boundary layer transition control on a mo... more In this paper, wind tunnel experiment was performed for boundary layer transition control on a morphing wing. Surface pressure fluctuations were measured using Kulite transducers at high sampling rate. A controller, linking the Kulites signals fluctuation to the smart material actuators, is incorporated to the control system, where the signals are analyzed and the transition location is detected. Several wind tunnel test runs for various Mach numbers and angles of attack were performed in the 6 × 9 ft 2 wind tunnel at the Institute for Aerospace Research at the National Research Council Canada. A rectangular finite aspect ratio wing, having a morphing airfoil cross section due to a flexible skin installed on the upper surface of the wing, was instrumented with sixteen Kulite transducers. The Mach number was varied from 0.2 to 0.3 and the angle of attack between -1 o and 2 o . Unsteady pressure signals were recorded and analyzed and a thorough comparison, in terms of mean pressure coefficients and their standard deviations, was performed against theoretical predictions using the XFoil computational fluid dynamics code. The unsteady pressure signals were analyzed through FFT spectral decomposition for detecting the Tollmien-Schlichting waves frequencies that trigger transition. In addition, infra red measurements were performed to asses the performance of the Kulite transducers in detecting the transition location and serve as an additional validation of the XFoil code in predicting the transition location .

International Conference on Informatics in Control, Automation and Robotics, 2010

Journal of Aircraft, 2010

... The infrared measurements were performed during wind tunnel tests by Dr. Youssef Merbaki. ...... more ... The infrared measurements were performed during wind tunnel tests by Dr. Youssef Merbaki. ... [2] Popov. AV., Labib, M., Fays, J., Botez, RM, 2008, Closed loop control simulations on a morphing laminar airfoil using shape memory alloys actuators, AIAA Journal of Aircraft, Vol. ...

icas.org

A large-scale multi-disciplinary research project, CRIAQ 7.1, was undertaken to investigate a mor... more A large-scale multi-disciplinary research project, CRIAQ 7.1, was undertaken to investigate a morphing wing concept for aircraft aerodynamic performance improvement over various flow conditions. The collaborators were

nt.ntnu.no

Journal of Aircraft, May 22, 2012

Icinco, 2010

Journal of Aircraft, 2010

In this paper, wind tunnel experiment was performed for boundary layer transition control on a mo... more In this paper, wind tunnel experiment was performed for boundary layer transition control on a morphing wing. Surface pressure fluctuations were measured using Kulite transducers at high sampling rate. A controller, linking the Kulites signals fluctuation to the smart material actuators, is incorporated to the control system, where the signals are analyzed and the transition location is detected. Several wind tunnel test runs for various Mach numbers and angles of attack were performed in the 6 × 9 ft 2 wind tunnel at the Institute for Aerospace Research at the National Research Council Canada. A rectangular finite aspect ratio wing, having a morphing airfoil cross section due to a flexible skin installed on the upper surface of the wing, was instrumented with sixteen Kulite transducers. The Mach number was varied from 0.2 to 0.3 and the angle of attack between -1 o and 2 o . Unsteady pressure signals were recorded and analyzed and a thorough comparison, in terms of mean pressure coefficients and their standard deviations, was performed against theoretical predictions using the XFoil computational fluid dynamics code. The unsteady pressure signals were analyzed through FFT spectral decomposition for detecting the Tollmien-Schlichting waves frequencies that trigger transition. In addition, infra red measurements were performed to asses the performance of the Kulite transducers in detecting the transition location and serve as an additional validation of the XFoil code in predicting the transition location .

International Conference on Informatics in Control, Automation and Robotics, 2010

Journal of Aircraft, 2010

icas.org