Ruxandra Botez | École de Technologie Supérieure (original) (raw)

Papers by Ruxandra Botez

Research paper thumbnail of Transition Point Detection from the Surface Pressure Distribution for Controller Design

Journal of Aircraft, 2008

Research paper thumbnail of Methodology for Aerodynamic Model Generation for the B-427 Helicopter in Hover and Forward Flight by use of Flight Test Data

In this paper, a method for the correction of a flight dynamics model to account for ground effec... more In this paper, a method for the correction of a flight dynamics model to account for ground effect in hovering flight is presented for a helicopter. This method is derived using only flight test data. Performance correlations are first derived for a helicopter in hover. In hover out of ground effect, we estimate relationships for torque coefficient with respect to collective position, as well as torque coefficient with respect to thrust coefficient. In ground effect, a correction for the relationship between thrust coefficient and torque coefficient with respect to the main rotor height was computed in order to obtain an equation for the main rotor thrust coefficient with respect to collective position and height above ground. A procedure is then suggested to use these performance relationships to correct terms in the control derivatives matrix of the linear equation describing the helicopter dynamics in hover.

Research paper thumbnail of Closed-Loop Control Simulations on a Morphing Wing

Journal of Aircraft, 2008

The main objective of the project is to develop a system for the active control of wing airfoil g... more The main objective of the project is to develop a system for the active control of wing airfoil geometry during flight to allow drag reduction. Drag reduction on a wing can be achieved by modifications in the laminar to turbulent flow transition point position, which should move toward the trailing edge of the airfoil wing. As the transition point plays a crucial part in this project, this paper focuses on the control of its position on the airfoil, as an effect of the deflection control on a morphing wing airfoil equipped with a flexible skin. The reference airfoil is the laminar WTEA-TE1 airfoil, on which a flexible skin is located; its geometry is modified by the use of a single point control, where it is assumed that one actuator acts. The Mach number, angle of attack, and deflection allow us to calculate the pressures and transition point positions at each step. The varying inputs are the deflections and the angles of attack. As they both change, the transition point position changes accordingly. A model of a shape memory alloy has been carried out in the MATLAB®/Simulink environment. Hence, the challenge is to perform the control with a shape memory alloy in the closed loop, as it has a nonlinear behavior. Several controllers, such as a proportional integral derivative controller, a proportional controller, and variables gains, are therefore necessary to control the shape memory alloy and the entire closed loop. Three simulations have been carried out to validate the control. The first simulation keeps the angle of attack constant and is performed for successive deflections. The second simulation considers different steps for the deflection but adds a sinusoidal component for the angle of attack; this simulation is closer to the cruise flight regime. During the third simulation, both the angle of attack and the deflection are modeled as a sinusoidal wave. The outputs (the deflection and the transition point position) are well controlled and the results are very good. Hence, it is concluded that this original method of control is suitable for the control of the transition point position from the laminar to turbulent region on a morphing wing airfoil.

Research paper thumbnail of Towards Drag Reduction on a Morphing Wing by Transition Detection and Delay using Kulite Sensors and Smart Material Actuators

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 .

Research paper thumbnail of Design and experimental validation of a combined PI and Bi-positional laws controller for delaying the transition from laminar flow to turbulent flow over a morphing wing

Lecture Notes in Electrical Engineering, 2011

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.

Research paper thumbnail of Smart concepts for actuation system and its control in a morphing wing

ima.ro

The objective of this research work is the development of an actuation control concept for a new ... more The objective of this research work is the development of an actuation control concept for a new morphing wing mechanism using smart materials made of Shape Memory Alloy (SMA) for the actuators and surface mounted pressure sensors. These actuators modify the upper wing surface, made of a flexible skin, so that the laminar-to-turbulent transition point moves close to the wing airfoil trailing edge. An intelligent controller was used for the open loop development step of the morphing wing project, and the closed loop of the morphing wing system included, as an internal loop, the controller actuation lines, based on the pressure information received from the sensors and on the transition point position estimation. The strong nonlinearities of the SMA actuators' characteristics and the system requirements led to the choice of a Fuzzy Logic Controller. The input-output mapping of the fuzzy model was designed taking account of the system's error and change in error. After preliminary numerical simulations using to tune the controller, an experimental validation was performed. The experimental validation consisted in experimental bench tests in laboratory conditions in the absence of aerodynamic forces, and in wind tunnel tests; the transition point real time position detection and visualization were realized.

Research paper thumbnail of Closed-Loop Control Validation of a Morphing Wing Using Wind Tunnel Tests

Journal of Aircraft, 2010

In this paper, a rectangular finite aspect ratio wing, having a WTEA reference airfoil cross-sect... more In this paper, a rectangular finite aspect ratio wing, having a WTEA reference airfoil cross-section, was considered. The wing upper surface was made of a flexible composite material and instrumented with Kulite pressure sensors, and two smart memory alloys actuators. Unsteady pressure signals were recorded and visualized in real time while the morphing wing was being deformed to reproduce various airfoil shapes by controlling the two actuators displacements. The controlling procedure was performed using two methods which are described in the paper. Several wind tunnel test runs were performed for various angles of attack and Reynolds numbers in the 6'×9' wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC). The Mach number was varied from 0.2 to 0.3, the Reynolds numbers varied between 2.29 million and 3.36 million, and the angles of attack range was within -1º to 2 o . Wind tunnel measurements are presented for airflow boundary layer transition detection using high sampling rate pressure sensors.

Research paper thumbnail of Ground Dynamics Model Validation for a Simulator Certification

Research paper thumbnail of New Formulation of the Ground Dynamics Model Generation and Validation by use of Flight Test Data

This paper outlines a new formulation for a ground dynamics model for a commercial helicopter des... more This paper outlines a new formulation for a ground dynamics model for a commercial helicopter describing the helicopter's dynamic after touchdown. The inputs of the ground dynamics model are the forces, moments, orientations and velocities at touchdown. It returns as output the forces and moments produced by the ground on the helicopter. Expressions for forces and moments as function of the friction coefficient between the skids and the ground and the system stiffness and damping are presented. The system stiffness and damping are defined between the touchdown point and the center of mass in each of the helicopter degree of freedom. Expressions for the stiffness, damping and friction coefficients as function of forces and velocities after touchdown still need to be derived. These expressions will be formulated to match normal and autorotation landing data of a helicopter.

Research paper thumbnail of Ground Dynamics Model Validation by use of Landing Flight Test Data

Research paper thumbnail of Validation of Laminar to Turbulent Transition on a Wing Airfoil

Research paper thumbnail of Determination of the Transition Point on the Upper Surface of a Wing Airfoil

The XFoil code is used to trace the pressure coefficient distribution versus the airfoil chord an... more The XFoil code is used to trace the pressure coefficient distribution versus the airfoil chord and to calculate the transition point position. Two interpolation methods: spline and Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) are used to trace the pressure coefficient distribution, and their first and second derivatives versus the airfoil chord. For 119 cases we obtained a mean error for the transition point position of 0.23% of the chord with the PCHIP method and 0.33% of the chord by using the spline method, with respect to the XFoil code. Therefore, PCHIP method was found to be better than the spline method.

Research paper thumbnail of Open Loop Control of the Transition Point Position on a Morphing Wing

Research paper thumbnail of Laminar to turbulent flow transition control on a morphing wing equipped with smart actuators and optical sensors

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. During the first part of the paper, the concept used for closed loop morphing wing controller is presented, while in the second part of this paper, the new methodology used for two neuro-fuzzy controllers’ identification and validation is described. Preliminary experimental results were obtained on a test bench for the smart material actuators (SMA) modeling and in a wind tunnel for the optical sensor pressure measurements variations with the temperature. The findings in this paper will be combined to build a final closed loop controller for transition point displacement towards the airfoil trailing edge by use of smart actuators and optical sensors. Methodologies and results will be further used to validate the experim...

Research paper thumbnail of Variations in Optical Sensor Pressure Measurements due to Temperature in Wind Tunnel Testing

Journal of Aircraft, 2009

In this paper, wind-tunnel measurements are presented for the airflow fluctuation detection using... more In this paper, wind-tunnel measurements are presented for the airflow fluctuation detection using pressure optical sensors. Twenty-one wind-tunnel test runs for various Mach numbers, angles of attack, and Reynolds numbers 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 half-wing, having a NACA 4415 cross section, was considered with its upper surface instrumented with pressure taps, pressure optical sensors, and one Kulite transducer. The Mach number was varied from 0.1 to 0.3 and the angle of attack range was within 3 to 3 deg. Unsteady pressure signals were recorded and a thorough comparison, in terms of unsteady and mean pressure coefficients, was performed between the measurements from the three sets of pressure transducers. Temperature corrections were considered in the pressure measurements by optical sensors. Comparisons were also performed against theoretical predictions using the XFoil computational fluid dynamics code, and mean errors smaller than 10% were noticed between the measured and the predicted data.

Research paper thumbnail of Adaptive neuro-fuzzy controllers for an open-loop morphing wing system

Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 2009

A new method for the realization of two neuro-fuzzy controllers for a morphing wing design applic... more A new method for the realization of two neuro-fuzzy controllers for a morphing wing design application is here presented. The controllers' main function is to correlate each set of pressure differences, calculated between the optimized and the reference airfoil, with each of the airfoil deformations produced by the actuators' system. The pressures are calculated at different chord positions and will be also measured during wind tunnel tests. During a first identification phase, the two Fuzzy Inference Systems (FIS) from the controllers' structure are generated for sixteen flight conditions characterized by Mach numbers and angles of attack. Next, the Fuzzy Inference Systems are optimized with the Matlab function Adaptive Neuro-Fuzzy Inference System (ANFIS) by training over different epochs. Finally, the controllers are validated for the other thirty-three flight conditions of the open loop morphing wing system. This is the first time that such a method of relating the pressure differences to airfoil displacements has been conceived and used in an open loop morphing wing controller system.

Research paper thumbnail of Morphing Wing Real Time Optimization in Wind Tunnel Tests

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.

Research paper thumbnail of Controller optimization in real time for a morphing wing in a wind tunnel

Proceedings of the Mediterranean Electrotechnical Conference - MELECON, 2010

Wind Tunnel Test results of a real time optimization of a morphing wing in wind tunnel for delayi... more Wind Tunnel Test results of a real time optimization of a morphing wing in wind tunnel for delaying the transition towards the trailing edge are presented.

Research paper thumbnail of Drag Reduction by Improving Laminar Flows past Morphing Configurations

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 .

Research paper thumbnail of A Morphing Wing used Shape Memory Alloy Actuators New Control Technique with Bi-positional and PI Laws Optimum Combination - Part 2: Experimental Validation

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

Research paper thumbnail of Transition Point Detection from the Surface Pressure Distribution for Controller Design

Journal of Aircraft, 2008

Research paper thumbnail of Methodology for Aerodynamic Model Generation for the B-427 Helicopter in Hover and Forward Flight by use of Flight Test Data

In this paper, a method for the correction of a flight dynamics model to account for ground effec... more In this paper, a method for the correction of a flight dynamics model to account for ground effect in hovering flight is presented for a helicopter. This method is derived using only flight test data. Performance correlations are first derived for a helicopter in hover. In hover out of ground effect, we estimate relationships for torque coefficient with respect to collective position, as well as torque coefficient with respect to thrust coefficient. In ground effect, a correction for the relationship between thrust coefficient and torque coefficient with respect to the main rotor height was computed in order to obtain an equation for the main rotor thrust coefficient with respect to collective position and height above ground. A procedure is then suggested to use these performance relationships to correct terms in the control derivatives matrix of the linear equation describing the helicopter dynamics in hover.

Research paper thumbnail of Closed-Loop Control Simulations on a Morphing Wing

Journal of Aircraft, 2008

The main objective of the project is to develop a system for the active control of wing airfoil g... more The main objective of the project is to develop a system for the active control of wing airfoil geometry during flight to allow drag reduction. Drag reduction on a wing can be achieved by modifications in the laminar to turbulent flow transition point position, which should move toward the trailing edge of the airfoil wing. As the transition point plays a crucial part in this project, this paper focuses on the control of its position on the airfoil, as an effect of the deflection control on a morphing wing airfoil equipped with a flexible skin. The reference airfoil is the laminar WTEA-TE1 airfoil, on which a flexible skin is located; its geometry is modified by the use of a single point control, where it is assumed that one actuator acts. The Mach number, angle of attack, and deflection allow us to calculate the pressures and transition point positions at each step. The varying inputs are the deflections and the angles of attack. As they both change, the transition point position changes accordingly. A model of a shape memory alloy has been carried out in the MATLAB®/Simulink environment. Hence, the challenge is to perform the control with a shape memory alloy in the closed loop, as it has a nonlinear behavior. Several controllers, such as a proportional integral derivative controller, a proportional controller, and variables gains, are therefore necessary to control the shape memory alloy and the entire closed loop. Three simulations have been carried out to validate the control. The first simulation keeps the angle of attack constant and is performed for successive deflections. The second simulation considers different steps for the deflection but adds a sinusoidal component for the angle of attack; this simulation is closer to the cruise flight regime. During the third simulation, both the angle of attack and the deflection are modeled as a sinusoidal wave. The outputs (the deflection and the transition point position) are well controlled and the results are very good. Hence, it is concluded that this original method of control is suitable for the control of the transition point position from the laminar to turbulent region on a morphing wing airfoil.

Research paper thumbnail of Towards Drag Reduction on a Morphing Wing by Transition Detection and Delay using Kulite Sensors and Smart Material Actuators

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 .

Research paper thumbnail of Design and experimental validation of a combined PI and Bi-positional laws controller for delaying the transition from laminar flow to turbulent flow over a morphing wing

Lecture Notes in Electrical Engineering, 2011

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.

Research paper thumbnail of Smart concepts for actuation system and its control in a morphing wing

ima.ro

The objective of this research work is the development of an actuation control concept for a new ... more The objective of this research work is the development of an actuation control concept for a new morphing wing mechanism using smart materials made of Shape Memory Alloy (SMA) for the actuators and surface mounted pressure sensors. These actuators modify the upper wing surface, made of a flexible skin, so that the laminar-to-turbulent transition point moves close to the wing airfoil trailing edge. An intelligent controller was used for the open loop development step of the morphing wing project, and the closed loop of the morphing wing system included, as an internal loop, the controller actuation lines, based on the pressure information received from the sensors and on the transition point position estimation. The strong nonlinearities of the SMA actuators' characteristics and the system requirements led to the choice of a Fuzzy Logic Controller. The input-output mapping of the fuzzy model was designed taking account of the system's error and change in error. After preliminary numerical simulations using to tune the controller, an experimental validation was performed. The experimental validation consisted in experimental bench tests in laboratory conditions in the absence of aerodynamic forces, and in wind tunnel tests; the transition point real time position detection and visualization were realized.

Research paper thumbnail of Closed-Loop Control Validation of a Morphing Wing Using Wind Tunnel Tests

Journal of Aircraft, 2010

In this paper, a rectangular finite aspect ratio wing, having a WTEA reference airfoil cross-sect... more In this paper, a rectangular finite aspect ratio wing, having a WTEA reference airfoil cross-section, was considered. The wing upper surface was made of a flexible composite material and instrumented with Kulite pressure sensors, and two smart memory alloys actuators. Unsteady pressure signals were recorded and visualized in real time while the morphing wing was being deformed to reproduce various airfoil shapes by controlling the two actuators displacements. The controlling procedure was performed using two methods which are described in the paper. Several wind tunnel test runs were performed for various angles of attack and Reynolds numbers in the 6'×9' wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC). The Mach number was varied from 0.2 to 0.3, the Reynolds numbers varied between 2.29 million and 3.36 million, and the angles of attack range was within -1º to 2 o . Wind tunnel measurements are presented for airflow boundary layer transition detection using high sampling rate pressure sensors.

Research paper thumbnail of Ground Dynamics Model Validation for a Simulator Certification

Research paper thumbnail of New Formulation of the Ground Dynamics Model Generation and Validation by use of Flight Test Data

This paper outlines a new formulation for a ground dynamics model for a commercial helicopter des... more This paper outlines a new formulation for a ground dynamics model for a commercial helicopter describing the helicopter's dynamic after touchdown. The inputs of the ground dynamics model are the forces, moments, orientations and velocities at touchdown. It returns as output the forces and moments produced by the ground on the helicopter. Expressions for forces and moments as function of the friction coefficient between the skids and the ground and the system stiffness and damping are presented. The system stiffness and damping are defined between the touchdown point and the center of mass in each of the helicopter degree of freedom. Expressions for the stiffness, damping and friction coefficients as function of forces and velocities after touchdown still need to be derived. These expressions will be formulated to match normal and autorotation landing data of a helicopter.

Research paper thumbnail of Ground Dynamics Model Validation by use of Landing Flight Test Data

Research paper thumbnail of Validation of Laminar to Turbulent Transition on a Wing Airfoil

Research paper thumbnail of Determination of the Transition Point on the Upper Surface of a Wing Airfoil

The XFoil code is used to trace the pressure coefficient distribution versus the airfoil chord an... more The XFoil code is used to trace the pressure coefficient distribution versus the airfoil chord and to calculate the transition point position. Two interpolation methods: spline and Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) are used to trace the pressure coefficient distribution, and their first and second derivatives versus the airfoil chord. For 119 cases we obtained a mean error for the transition point position of 0.23% of the chord with the PCHIP method and 0.33% of the chord by using the spline method, with respect to the XFoil code. Therefore, PCHIP method was found to be better than the spline method.

Research paper thumbnail of Open Loop Control of the Transition Point Position on a Morphing Wing

Research paper thumbnail of Laminar to turbulent flow transition control on a morphing wing equipped with smart actuators and optical sensors

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. During the first part of the paper, the concept used for closed loop morphing wing controller is presented, while in the second part of this paper, the new methodology used for two neuro-fuzzy controllers’ identification and validation is described. Preliminary experimental results were obtained on a test bench for the smart material actuators (SMA) modeling and in a wind tunnel for the optical sensor pressure measurements variations with the temperature. The findings in this paper will be combined to build a final closed loop controller for transition point displacement towards the airfoil trailing edge by use of smart actuators and optical sensors. Methodologies and results will be further used to validate the experim...

Research paper thumbnail of Variations in Optical Sensor Pressure Measurements due to Temperature in Wind Tunnel Testing

Journal of Aircraft, 2009

In this paper, wind-tunnel measurements are presented for the airflow fluctuation detection using... more In this paper, wind-tunnel measurements are presented for the airflow fluctuation detection using pressure optical sensors. Twenty-one wind-tunnel test runs for various Mach numbers, angles of attack, and Reynolds numbers 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 half-wing, having a NACA 4415 cross section, was considered with its upper surface instrumented with pressure taps, pressure optical sensors, and one Kulite transducer. The Mach number was varied from 0.1 to 0.3 and the angle of attack range was within 3 to 3 deg. Unsteady pressure signals were recorded and a thorough comparison, in terms of unsteady and mean pressure coefficients, was performed between the measurements from the three sets of pressure transducers. Temperature corrections were considered in the pressure measurements by optical sensors. Comparisons were also performed against theoretical predictions using the XFoil computational fluid dynamics code, and mean errors smaller than 10% were noticed between the measured and the predicted data.

Research paper thumbnail of Adaptive neuro-fuzzy controllers for an open-loop morphing wing system

Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 2009

A new method for the realization of two neuro-fuzzy controllers for a morphing wing design applic... more A new method for the realization of two neuro-fuzzy controllers for a morphing wing design application is here presented. The controllers' main function is to correlate each set of pressure differences, calculated between the optimized and the reference airfoil, with each of the airfoil deformations produced by the actuators' system. The pressures are calculated at different chord positions and will be also measured during wind tunnel tests. During a first identification phase, the two Fuzzy Inference Systems (FIS) from the controllers' structure are generated for sixteen flight conditions characterized by Mach numbers and angles of attack. Next, the Fuzzy Inference Systems are optimized with the Matlab function Adaptive Neuro-Fuzzy Inference System (ANFIS) by training over different epochs. Finally, the controllers are validated for the other thirty-three flight conditions of the open loop morphing wing system. This is the first time that such a method of relating the pressure differences to airfoil displacements has been conceived and used in an open loop morphing wing controller system.

Research paper thumbnail of Morphing Wing Real Time Optimization in Wind Tunnel Tests

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.

Research paper thumbnail of Controller optimization in real time for a morphing wing in a wind tunnel

Proceedings of the Mediterranean Electrotechnical Conference - MELECON, 2010

Wind Tunnel Test results of a real time optimization of a morphing wing in wind tunnel for delayi... more Wind Tunnel Test results of a real time optimization of a morphing wing in wind tunnel for delaying the transition towards the trailing edge are presented.

Research paper thumbnail of Drag Reduction by Improving Laminar Flows past Morphing Configurations

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 .

Research paper thumbnail of A Morphing Wing used Shape Memory Alloy Actuators New Control Technique with Bi-positional and PI Laws Optimum Combination - Part 2: Experimental Validation

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