a vision based automatic landing method fro fixed wing uavs

A Vision-Based Automatic Landing Method For Fixed-Wing Unmanned Aerial Vehicles

Name:

Sahana Sridhar

1SG06EC064

Guided by:

Mrs.Shobha.K

Mrs.Padmavathi.H

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Introduction

• A system for small-size, fixed-wing unmanned aerial

vehicles (UAV’s).

• Based on vision in front of the vehicle.

• Visual servoing algorithm is used to improve accuracy

of the landing

• Color- and moment-based target detection.

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Automatic landing method for fixed wing UAVs

Manual landing

• Landing is the most accident-prone stage airplanes.

• Pilot obtains visual info by naked eyes live images taken by onboard cameras.

• Piloting outside needs lot of practice.

• Nearly 70% of mishaps and 50% of fixed-wing UAVs such as Hunter and Pioneer suffer accidents during landing.

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Automatic landing method for fixed wing UAVs

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Vision-based Automatic landing

• A camera and a vision processing unit onboard.

• Detects the runway or other visual markers.

• Guide the vehicle to the touchdown point with good accuracy.

• Automatic landing systems control velocity of UAV’s more accurately.

Automatic landing method for fixed wing UAVs

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• UAVs fly without onboard pilots.

• They have become increasingly popular in military operations.

• UAVs use energy-absorption technique.

• These are simple and they use high rate of survivability.

Unmanned aerial vehicles(UAVs)

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System Description

• Proposed landing system consists of three

major components:

Inflated dome as a visual marker,

A vision processing unit,

Flight controller using visual servoing algorithm.

• Vision system is integrated with an MEMS based inertial

measurement unit (IMU).

Automatic landing method for fixed wing UAVs

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Description on the proposed approach

Automatic landing method for fixed wing UAVs

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Airframe and Avionics

• In this research we make use of BWB-based UAV’s.

• BWB has only 2 control surfaces at the trailing edge know as elevons.

• The fuselage houses the flight computer, IMU, battery and radio receiver, also vehicle has a DC motor.

•The vehicle is resistant to shocks and crashes.

Automatic landing method for fixed wing UAVs

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Blended-wing body (BWB) UAV Test bed

Automatic landing method for fixed wing UAVs

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Avionics hardware architecture

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Landing equipment

• An arresting device is needed.

We propose a dome-shaped air bag.

• The dome is constructed with sturdy nylon of red color.

• The vehicle would simply fly into the dome at low speed with a reasonable incident angle.

• Dome serves as visual cue and recovery net is responsible for arresting the vehicle.

Automatic landing method for fixed wing UAVs

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Vision Algorithms The proposed vision algorithm consists of:A color-based detection,A moment-based detection, and Visual servoing.

Proposed landing dome and recovery net

Automatic landing method for fixed wing UAVs

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Color-based target detection

• Color can provide an efficient vision.

• It can identify the target color regions with faster speeds.

• Good results are obtained under good lighting conditions.

• The dome’s color is the strongest visual cue.

• By making use of the moment invariant, specific target can be

found.

Automatic landing method for fixed wing UAVs

Roof Road sign Automobile Landing Dome

Hu’s moment 1 0.48560 0.20463 0.27423 0.21429

Hu’s moment 2 0.18327 0.00071 0.04572 0.01806

Hu’s moment 3 0.01701 0.00009 0.00193 0.00106

Hu’s moment 4 0.00911 0.00028 0.00098 0.000

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Moment based target detection:

• Multiple red objects are found by color based detection.

• Now it is required to determine whether the object is the landing dome or not.

• We use Hu’s method for high rate-detection for visual-based landing.

Four image moments are used for detection

Hu’s moment approach is applied to various red objects seen from space.

Hu’s moment value of various shapes

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Visual servoing:

• Is a method to control a robot using computer vision.

• Can be applied to the fixed-wing UAV.

• Landing dome from the center of the image represents the heading

and pitch deviation.

• When the heading and pitch angle errors are zero the vehicle flies

directly to the landing dome.

• The heading and pitch angle deviations are sent to the heading and

pitch angle controllers.

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Visual servoing scheme:

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Fig.1 Fig. 2

Fig. 3 Fig. 4

Sequence of images during landing to domeAutomatic landing method for fixed wing UAVs

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Sequence of images during landing to the recovery netAutomatic landing method for fixed wing UAVs

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Conclusion

• The domes distinctive color and shape provides a visual cue to

vision system without any mistakes.

• The vision algorithm detects the landing dome.

• Navigation sensors cannot provide accurate solutions, visual

servoing is implemented.

• The idea shows that the system is a viable approach for landing.

Automatic landing method for fixed wing UAVs

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References:

• www.wikipedia.org

• http://ieeeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1057692

• Intelligent robots and systems, 2007, IROS 2007. IEEE/RSJ international conference on.

• www.springerlink.com/index/80660XH9678W1810

• www.sciencedirect.com

Automatic landing method for fixed wing UAVs

Thank you!

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