The Challenge of Controlling a Small Mars Plane

Mapping Intimacies ◽

10.5772/intechopen.95507 ◽

2020 ◽

Author(s):

Seiki Chiba ◽

Mikio Waki

Keyword(s):

Wind Tunnel ◽

Power Control ◽

High Power ◽

Structural Model ◽

High Efficiency ◽

Wind Tunnel Test ◽

Martian Atmosphere ◽

Planetary Exploration ◽

Control Surface ◽

Dielectric Elastomers

Dielectric elastomers (DEs) are lightweight and high-power, making them ideal for power control in a planetary exploration spacecraft. In this chapter, we will discuss the control of an exploration airplane exploring the surface of Mars using DEs. This airplane requires lightweight and powerful actuators to fly in the rare Martian atmosphere. DEs are a possible candidate for use as actuator controlling the airplane since they have high power, and high efficiency. A structural model of a wing having a control surface, a DE, and a linkage was built and a wind tunnel test of a control surface actuation using a DE actuator was carried out.

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Wind Tunnel Testing of Composite Wing Flutter Speed due to Control Surface Excitation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.315.359 ◽

2013 ◽

Vol 315 ◽

pp. 359-363 ◽

Cited By ~ 1

Author(s):

Mahzan Muhammad Iyas ◽

Muhamad Sallehuddin ◽

Mat Ali Mohamed Sukri ◽

Mansor Mohd Shuhaimi

Keyword(s):

Wind Tunnel ◽

Dynamic Instability ◽

Wind Tunnel Test ◽

Control Surface ◽

Wind Tunnel Testing ◽

Structural Stiffness ◽

Wing Flutter ◽

Flutter Speed ◽

Surface Excitation ◽

Composite Wing

Flutter is a dynamic instability problem represents the interaction among aerodynamic forces and structural stiffness during flight. The study was conducted to investigate whether deflecting the control surface will affect the flutter speed and the flutter frequency. A wind tunnel test was performed using a flat plate wing made of composite material. It was found that by deflecting the control surface at 45°, the wing entered flutter state at wind speed of 28.1 m/s instead of 33.4 m/s. In addition, the flutter frequency also reduced from 224.52 Hz to 198.96 Hz. It was concluded that by deflecting the control surface, the wing experienced flutter at lower speed and frequency.

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Composite Wing Flutter Speed and Frequency due to Variable Control Surface Deflection in Low Speed Wind Tunnel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.390.3 ◽

2013 ◽

Vol 390 ◽

pp. 3-7

Author(s):

Muhammad Iyas Mahzan ◽

Sallehuddin Muhamad ◽

Sa’ardin Abdul Aziz ◽

Mohamed Sukri Mat Ali

Keyword(s):

Wind Tunnel ◽

Dynamic Instability ◽

Wind Tunnel Test ◽

Control Surface ◽

Wing Flutter ◽

Flutter Speed ◽

Surface Deflection ◽

Relationship Of ◽

Low Speed Wind Tunnel ◽

The Relationship

Flutter is a dynamic instability problem represents the interaction among structural, aerodynamic, elastic and inertial forces and occurred when the energy is continuously transformed by the surrounding fluids to a flying structure in the form of kinetic energy. The study was conducted to investigate the relationship of the control surface deflection angle to the flutter speed and the flutter frequency. A wind tunnel test was performed using a flat plate wing made of composite material. It was found that by deflecting the control surface up to 45°, the flutter speed reduced almost linearly from 35.6 m/s to 22.7 m/s. The flutter frequency greatly reduced from 48 Hz without the control surface deflected to 34 Hz with the control surface deflected at 15°. After 15° deflection up to 45°, the flutter frequency reduced almost linearly.

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Load prediction of hingeless helicopter rotors including drivetrain dynamics

CEAS Aeronautical Journal ◽

10.1007/s13272-020-00483-6 ◽

2021 ◽

Author(s):

Felix Weiss ◽

Christoph Kessler

Keyword(s):

Wind Tunnel ◽

Structural Model ◽

Wind Tunnel Test ◽

Major Change ◽

Load Prediction ◽

Baseline Case ◽

Time Marching ◽

Free Wake ◽

Blade Loads ◽

Cruise Flight

AbstractIn contrast to analyses with constrained hub speed, the present study includes the dynamic response of coupled rotor-drivetrain modes in the aeromechanic simulation of rotor blade loads. The structural model of the flexible Bo105 rotor-drivetrain system is coupled to aerodynamics modeled by an analytical formulation of unsteady blade element loads combined with a generalized dynamic wake or a free wake, respectively. For two flight states, i. e. cruise flight and large blade loading, a time-marching autopilot trim of the rotor-drivetrain system in wind tunnel configuration is performed. The simulation results are compared to those of a baseline case with constant rotor hub speed. The comparison reveals a major change in the blade passage frequency harmonics of the lead-lag loads. Beside the full drivetrain model, reduced models are shown to accurately represent the drivetrain influence on blade loads, if the eigenfrequency of the coupled second collective lead-lag/drivetrain mode is properly predicted. In a sensitivity analysis, this eigenfrequency is varied by stiffness modification of a reduced drivetrain model. The resulting changes in blade loads are correlated to this eigenfrequency, which serves as a simple though accurate classification of the drivetrain regarding its influence on vibratory blade loads. Finally, the potential to improve lead-lag load predictions by application of a drivetrain model is demonstrated through the comparison of simulated loads with measurements from a wind tunnel test.

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Acquisition of Swept Aerodynamic Data by the Consecutive Changing of Wing Model Configuration in a Wind Tunnel Test Using Remote Feedback Control

Aerospace ◽

10.3390/aerospace8080217 ◽

2021 ◽

Vol 8 (8) ◽

pp. 217

Author(s):

Ken Wakimoto ◽

Kazuhisa Chiba ◽

Hiroyuki Kato ◽

Kazuyuki Nakakita

Keyword(s):

Feedback Control ◽

Wind Tunnel ◽

Deflection Angle ◽

Wind Tunnel Test ◽

Control Surface ◽

Wind Tunnel Tests ◽

The Deflection Angle ◽

Physical Phenomena ◽

3D Wing ◽

Remote Feedback

This study conducted wind tunnel tests with consecutive deflection angle changes on a three-dimensional (3D) wing with a control surface to procure aerodynamic data by sweeping the deflection angle. Configuration changes of a wind tunnel test model, such as changing the deflection angle of control surfaces, are usually performed manually with the ventilation suspended. Hence, the number of configurations that can be implemented within a confined test period is restricted; the aerodynamic data gained are discrete values. To accomplish continuous angular modulation would dramatically improve the ability by sweeping through the aerodynamic data in wind tunnel tests, enhancing the test system as a tool for discussing complex physical phenomena. Thus, this study created a compact remote feedback control system using optical measurement to continuously obtain high-precision aerodynamic data without stopping the wind tunnel, eliminating human operation. In particular, this study targets a 3D wing wind tunnel model with a control surface, which is more challenging to fabricate, miniaturizing the system in a model. The system consequently attained consecutive aerodynamic data multiple times under numerous configurations, which had been impracticable to reach in the past, within a wind tunnel test period of several days, thereby dramatically increasing the testing capability. The reproducibility was quantitatively verified by comparing the multiple data for the identical configurations. Furthermore, the reliability was demonstrated using discrete data obtained by conventional stepwise deflection angle adjustments. Eventually, the system was able to grasp physical phenomena involving hysteresis.

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Group Delay in Digital Filter Induced Instability of a Two-Dimensional Airfoil Active Flutter Suppression System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.226-228.64 ◽

2012 ◽

Vol 226-228 ◽

pp. 64-69

Author(s):

Ming Li Yu

Keyword(s):

Wind Tunnel ◽

Digital Filter ◽

Group Delay ◽

Numerical Study ◽

Wind Tunnel Test ◽

Control Surface ◽

Two Dimensional ◽

Flutter Suppression ◽

Active Flutter Suppression ◽

Suppression System

The presented paper deals with the group delay in the digital filter induced instability of a two dimensional airfoil section active flutter suppression system. Firstly, the aeroelastic model of the airfoil with an ultrasonic motor actuated control surface is set up; secondly, both H∞and μ robust controllers are designed; and then, the group delay induced instability in wind tunnel test is presented; finally, through a combined theoretical and numerical study, the test phenomenon is well explained. Wind tunnel experiments and numerical simulations demonstrate that long enough group delay in digital filter can induce instability of flutter control system, the flutter under control will decrease first, and then become another flutter of lower frequency and moderated amplitude, and μ controller works better than H∞controller on the same condition.

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Blade Structural Load/Airload Correlation on a Slowed Mach-Scaled Rotor at High Advance Ratios

Journal of the American Helicopter Society ◽

10.4050/jahs.65.042003 ◽

2020 ◽

Vol 65 (4) ◽

pp. 1-14

Author(s):

Xing Wang ◽

Yong Su Jung ◽

James Baeder ◽

Inderjit Chopra

Keyword(s):

Wind Tunnel ◽

Structural Model ◽

Reverse Flow ◽

Pressure Sensors ◽

Wind Tunnel Test ◽

Design Feature ◽

Flow Region ◽

Rotor Blades ◽

Data Correlation ◽

Advance Ratio

To expand the cruise speed of a compound helicopter, alleviating the compressibility effects on the advancing side with reduced rotor RPM is proved to be an effective design feature, which results in high advance ratio flight regime. To investigate the aerodynamic phenomena at high advance ratios and provide data for the validation of analytical tools, a series of wind tunnel tests were conducted progressively in the Glenn L. Martin Wind Tunnel with a 33.5-inch radius fourbladed articulated rotor. In a recent wind tunnel test, the rotor blades were instrumented with pressure sensors and strain gauges at 30% radius, and pressure data were acquired to calculate the sectional airloads by surface integration up to an advance ratio of 0.8. The experimental results of rotor performance, control angles, blade airloads, and structural loads were compared with the predictions of comprehensive analysis and computational fluid dynamics (CFD) analysis coupled with computational structural dynamics (CSD) structural model. The paper focuses on the data correlation between experimental pressure, airload, and structural load data and the CFD/CSD predicted results at various collective and shaft tilt angles. Overall, the data correlation was found satisfactory, and the study provided some insights into the aerodynamic mechanisms that affect the rotor airload and performance, in particular the mechanisms of backward shaft tilt, the effect of hub/shaft wake, and the formation of dynamic stall in the reverse flow region.

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Design, Manufacture and Wind Tunnel Test of a Modular FishBAC Wing with Novel 3D Printed Skins

Applied Sciences ◽

10.3390/app12020652 ◽

2022 ◽

Vol 12 (2) ◽

pp. 652

Author(s):

Andrés E. Rivero ◽

Stephane Fournier ◽

Rafael M. Heeb ◽

Benjamin K. S. Woods

Keyword(s):

Wind Tunnel ◽

Modular Design ◽

Thermoplastic Polyurethane ◽

Lift Coefficient ◽

Wind Tunnel Test ◽

Fish Bone ◽

Control Surface ◽

Morphing Wing ◽

3D Printed ◽

Skin Panels

This paper introduces a new modular Fish Bone Active Camber morphing wing with novel 3D printed skin panels. These skin panels are printed using two different Thermoplastic Polyurethane (TPU) formulations: a soft, high strain formulation for the deformable membrane of the skin, reinforced with a stiffer formulation for the stringers and mounting tabs. Additionally, this is the first FishBAC device designed to be modular in its installation and actuation. Therefore, all components can be removed and replaced for maintenance purposes without having to remove or disassemble other parts. A 1m span, 0.27m chord morphing wing with a 25% chord FishBAC was built and tested mechanically and in a low-speed wind tunnel. Results show that the new design is capable of achieving the same large changes in airfoil lift coefficient (approximate ΔCL≈0.55) with a low drag penalty seen in previous FishBAC work, but with a much simpler, practical and modular design. Additionally, the device shows a change in the pitching moment coefficient of ΔCM≈0.1, which shows the potential that the FishBAC has as a control surface.

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