Vertical Take-Off and Landing Flying Robots

Towards miniature flying robotic paltforms


Samir Bouabdallah, PhD Student


Recent developments in high density power storage, in sensors and actuators technology; make autonomous miniature flying robots imaginable. Designing such a robotic platform is a multidisciplinary challenge which requires competences in several fields, mainly: aerodynamics, control systems, electronics and data processing. However, during this project we focus on design methodology and control strategies development, specifically for small-scale VTOL systems.

Quadrotor flying robot design and control

OS4* is an electrically powered four-rotors miniature helicopter developped towards fully autonomous operation in indoor/outdoor environments.

The major goal of this research is the development and implementation of an active control system for a quadrotor helicopter. However, one has to consider seriously the design aspect of the problem in order to get rid of the hardware limitations and achieve control simplification. Controlling a VTOL flying robot is basically dealing with highly unstable dynamics and strong axes coupling. Good results can only be reached with high bandwidth actuators and reliable hardware. Main control and design results are presented in the publications.

*Omnidirectional Stationary Flying OUtstretched Robot
  NEWS & EVENTS

[20 August 2005] AERO: The "Unmanned Aerial Robotics Initiative", a coordination of all EPFL's aerial robotics research activities.

[9 Mar 2005] Colibri (EPFL) team selected for ESA parabolic flight campaign.

[20 February 2005] New proto of OS4 quadrotor robot is now ready.

[01 February 2005] New CoaX coaxial helicopter project launched
The second OS4 prototype is a fully autonomous quadrotor with 520g in mass and 720mm in span. It has the following features:
  • 30min autonomy estimation
  • One 15g (OEM) micro IMU from Xsens
  • Four 12g BLDC motors from LRK and controlers (special design)
  • Integrated computer module (special design)
  • 230g Lipo battery
  • WLAN, Bluetooth and RC communication modules
  • Ground Control Software
The first OS4 prototype is a simple cross with four DC motors and a micro IMU mounted on a test-bench. The data processing, the energy source and the motor control are off-board. It is mainly used for control strategies developement and system analysis. This system description and several videos are available in the related publications and links below. The flying part features are:
  • 235g in mass
  • 730mm in span
  • Four Faulhaber 1724 micro-motors
  • One 32g micro IMU from Xsens

Video Gallery (all flights are autonomous)

Project Status
  • Successful collision avoidance experiment based on sonars (June 2006) [Video in WMV, 1.6Mo],[Video in WMV, 1.5Mo]
  • Roll, Pitch, Yaw and Altitude autonomous control, all embedded (April 2006) [Video in WMV, 6.3Mo]
  • Extanded Kalman Filter for state estimation (April 2006)
  • Vision based positionning sensor for indoor navigation (March 2006)
  • Roll, Pitch, Yaw and Altitude autonomous control, all embedded (January 2006)
  • Obstacle avoidance controller integrated in the simulator (December 2006 - in collaboration with Prof. M.Becker)
  • New Integral Backstepping control (November 2005)
  • Advanced Quadrotor simulator ready under Matlab-Simulink R14 (July 2005)
  • New "OS4" robot with integrated avionics and energy device (February 2005) [Picture in JPG, 1Mo]
  • Integrated computer module design (December 2004) [Picture in JPG, 600Ko]
  • Brushless sensorless motor module design (June 2004) [Picture in JPG, 150Ko]
  • First autonomous flight (orientation control), the controller and the power source are still off-board (February 2004) [Video in MPG, 3Mo]
  • Roll, Pitch and Yaw angles controlled on test bench (October 2003) [Video in MPG, 3Mo]
  • Test bench design (September 2003)
  • Dynamic Modelling (August 2003)
  • State of the art survey

Related publications

Related projects
  • Vincent de Perrot: Implementation of an obstacle avoidance controller on the OS4 mini-helicopter (summer 2006) [Report in PDF, 2Mo]
  • Julien Epiney: Quadrotor helicopter hovering with vision (winter 2006) [Report in PDF, 3Mo]
  • Thierry Frank: Positionnement de robots volants par la vision (winter 2005) [Report in PDF, 4Mo]
  • Yves Stauffer: Analog PID module (summer 2004) [Report in PDF, 2Mo]
  • Andre Noth: Synthèse et Implémentation d'un contrôleur pour micro-hélicoptère à 04 rotors (winter 2004) [Report in PDF, 1Mo]
  • Adrien Brossard: Banc de test automatique pour groupe-moto-propulseur (winter 2004) [Report in PDF, 1Mo]
  • Marc Kunze: Hélicoptère indoor partie électronique/informatique (winter 2003) [Report in PDF, 500Ko]
  • Pierre-Olivier Latour: Computer based control system for a model helicopter (summer 2002) [Report in PDF, 1Mo]

Related Links

Miniature VTOL flying robots design and control

The flying robots downscaling is the principal challenge in this aspect of our research. This challenge creates several others because of the negative effects of the miniaturization. These effects are strongly present under a certain threshold, that is: fall of the propulsion system efficiency as a result of low reynolds numbers and actuators low efficiency, weakness of the available energy and a great tendency to high frequency oscillations.
CoaX 2 is the new version of a miniature coaxial helicopter robotic platform. This version has two separate BLDC motors in addition to several sensors and controllers. CoaX 2 has the ability to move horizontally by displacing its center of gravity in two axes.

CoaX 2 has the following features:

  • Two BLDC 12g motors
  • Two 3 blades propellers (special design)
  • 3 PIC microcontrolers 18F family
  • 2 servos for CoG displacement
  • 1 distance sensor for altitude measurement: SHARP GP2Y0A02YK
  • 1 accelerometer 2 axes: VTI SCA100T
  • 1 MEMS gyroscope: Analog ADXRS300
  • Bluetooth communicatiom module
CoaX is a miniature coaxial helicopter robotic platform currently under development. The aim of the project is to achieve a passively stable operation in roll and pitch rotations while maintaining a dynamic control on the horizontal linear motion. CoaX has the following features:
  • One BLDC 32g motor
  • Two 3 blades propellers (special design)
  • Bluetooth communicatiom module
Flying Alice is a very challenging project which aimed to provide Alice miniature rolling robot with the flying capability. Flying Alice has the following features:
  • Two DC Faulhaber 0806 motors
  • Two axes Accelerometer and Gyroscope from Analog
  • Electronic compass from Honeywell

Related projects

Related Links

New flying concepts

A cool application of the the WX concept, imagined by our X-plane expert Claudio. [Picture in JPG, 0.2Mo]

The complexity of the design and the control of miniaturized flying robots pushed us to seek for new flying concepts which could make it possible to increase the autonomy and reduce the size.

The picture beside shows the WX concept, it is a kind of linear propeller...

Related projects
  • No projects for the moment !

Related Links

Space related activities

Mars exploration is the best way to expand the scientific knowledge of Mars.

Autonomous mobile platforms as Sojourner or mars rover, offers a good alternative to explore and maneuver to scientifically interesting sites. However, large rocks and deep valleys stay unaccessible.

Flying platforms can cover large distances for a long periods and easily provide images, detect soil composition and sample the atmosphere of interesting sites.

Several projects are carried out often for ESA education program and/or students initiatives.

Related projects

Related Links

Resources

Media Coverage


General Links
  • AERO: "Unmanned Aerial Robotics Initiative", a joint effort of three EPFL labs: ASL, LIS, VRLAB
  • X-plane: powerfull aircraft simulator
  • Personnal web page and publications
  • A.Noth: Autonomous solar airplane, Sky-sailor
  • DIDEL: our main external partner for design components
  • J.C.Zufferey: Adaptive Vision-based Flying Robots
  • ETHZ: autonomously flying helicopter



Published: 28.02.03/sb       Last update: 03.07.06/sb