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Chatelard, Switzerland

Zufferey J.-C.,Ecole Polytechnique Federale de Lausanne | Beyeler A.,SenseFly | Floreano D.,SenseFly
International Journal of Micro Air Vehicles | Year: 2010

The ability to fly at low altitude while actively avoiding collisions with the terrain and objects such as trees and buildings is a great challenge for small unmanned aircraft. This paper builds on top of a control strategy called optiPilot whereby a series of optic-flow detectors pointed at divergent viewing directions around the aircraft main axis are linearly combined into roll and pitch commands using two sets of weights. This control strategy already proved successful at controlling flight and avoiding collisions in reactive navigation experiments. This paper describes how optiPilot can efficiently steer a flying platform during the critical phases of hand-launched take off and landing. It then shows how optiPilot can be coupled with a GPS in order to provide goal-directed, nap-of-the-earth flight control in presence of obstacles. Two fully autonomous flights of 25 minutes each are described where a 400-gram unmanned aircraft flies at approx. 10 m above ground in a circular path including two copses of trees requiring efficient collision avoidance actions.


Daynes S.,RMIT University | Lachenal X.,SenseFly | Weaver P.M.,University of Bristol
Thin-Walled Structures | Year: 2015

A morphing wing structure is presented which is designed to have zero torsional stiffness to minimise actuation requirements. The concept consists of carbon fibre reinforced plastic strips which are initially curved prior to being flattened and assembled into a grid-like structure in a heightened state of elastic strain energy. Varying the initial curvature of the strips, material properties and the assembled geometry enables the torsional stiffness to be tailored. A state of zero torsional stiffness can be obtained when there is a balance between the changes in strain energy associated with bending and twist deformations. © 2015 Elsevier Ltd. All rights reserved.


Briod A.,Ecole Polytechnique Federale de Lausanne | Zufferey J.-C.,SenseFly | Floreano D.,Ecole Polytechnique Federale de Lausanne
Autonomous Robots | Year: 2015

We aim at developing autonomous miniature hovering flying robots capable of navigating in unstructured GPS-denied environments. A major challenge is the miniaturization of the embedded sensors and processors that allow such platforms to fly by themselves. In this paper, we propose a novel ego-motion estimation algorithm for hovering robots equipped with inertial and optic-flow sensors that runs in real-time on a microcontroller and enables autonomous flight. Unlike many vision-based methods, this algorithm does not rely on feature tracking, structure estimation, additional distance sensors or assumptions about the environment. In this method, we introduce the translational optic-flow direction constraint, which uses the optic-flow direction but not its scale to correct for inertial sensor drift during changes of direction. This solution requires comparatively much simpler electronics and sensors and works in environments of any geometry. Here we describe the implementation and performance of the method on a hovering robot equipped with eight 0.65 g optic-flow sensors, and show that it can be used for closed-loop control of various motions. © 2015 Springer Science+Business Media New York


Halter A.,SenseFly
GIM International | Year: 2015

senseFly is a developer and producer of autonomous, ultra-light aerial imaging UAVs (also called 'drones') for professional applications. Based in the French-speaking region of Switzerland, the company provides professionals around the world with safe, easy-to-use aerial imaging tools that help them collect the geospatial data they need to make better decisions.


Zufferey J.-C.,Ecole Polytechnique Federale de Lausanne | Beyeler A.,SenseFly | Floreano D.,Ecole Polytechnique Federale de Lausanne
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2010

The ability to fly at low altitude while actively avoiding collisions with the terrain and other objects is a great challenge for small unmanned aircraft. This paper builds on top of a control strategy called optiPilot whereby a series of optic-flow detectors pointed at divergent viewing directions around the aircraft main axis are linearly combined into roll and pitch commands using two sets of weights. This control strategy already proved successful at controlling flight and avoiding collisions in reactive navigation experiments. This paper shows how optiPilot can be coupled with a GPS in order to provide goal-directed, nap-of-the-earth flight control in presence of static obstacles. Two fully autonomous flights of 25 minutes each are described where a 400-gram unmanned aircraft is flying at approx. 9 m above the terrain on a circular path including two copses of trees requiring efficient collision avoidance actions. ©2010 IEEE.

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