Novel Hyperacute Gimbal Eye for Implementing Precise Hovering and Target Tracking on Board a Quadrotor

International audienceThis paper presents a new minimalist bio-inspired artificial eye of only 24 pixels, able to locate accurately a target placed in its small field of view (10°). The eye is mounted on a very light custom-made gimbal system which makes the eye able to track faithfully a moving target. We have shown here, that our gimbal eye can be embedded onboard a small quadrotor to achieve accurate hovering with respect to a target placed onto the ground. Our aiborne oculomotor system was enhanced with a bio-inspired reflexe in charge to lock efficiently the robot’s gaze onto a target and compensate for the robot’s rotations and disturbances. The use of very few pixels allowed to implement a visual processing algorithm at a refresh rate as high as such as 400 Hz. This high refresh rate coupled to a very fast control of the eye’s orientation allowed the robot to track efficiently a target moving at a speed up to 200°/s

Local Positioning System Using Flickering Infrared LEDs

International audienceA minimalistic optical sensing device for the indoor localization is proposed to estimate the relative position between the sensor and active markers using amplitude modulated infrared light. The innovative insect-based sensor can measure azimuth and elevation angles with respect to two small and cheap active infrared light emitting diodes (LEDs) flickering at two different frequencies. In comparison to a previous lensless visual sensor that we proposed for proximal localization (less than 30 cm), we implemented: (i) a minimalistic sensor in terms of small size (10 cm 3), light weight (6 g) and low power consumption (0.4 W); (ii) an Arduino-compatible demodulator for fast analog signal processing requiring low computational resources; and (iii) an indoor positioning system for a mobile robotic application. Our results confirmed that the proposed sensor was able to estimate the position at a distance of 2 m with an accuracy as small as 2-cm at a sampling frequency of 100 Hz. Our sensor can be also suitable to be implemented in a position feedback loop for indoor robotic applications in GPS-denied environment

Construction d’une maquette de lévitation magnétique pour un aimant de quelques milligrammes

International audienceLa lévitation magnétique est un dispositif expérimental souvent présenté aux étudiants d'abord en simulation puis en travaux pratiques. La masse de l'objet mis en lévitation est rarement inférieure au gramme en raison de la difficulté de mesurer de très petits déplacements. De plus, les expériences sont souvent réalisées sur des maquettes commerciales. Dans cet article, nous abordons les concepts de la lévitation magnétique sous l'angle de l'expérimentation avec le défi de construire une maquette capable de mettre en équilibre un aimant de quelques milligrammes. Nous avons utilisé ce dispositif pédagogique dans le cadre de la formation des étudiants de la licence au master et écoles d'ingénieurs

A novel 1-gram insect based device measuring visual motion along 5 optical directions

International audienceAutopilots for micro aerial vehicles (MAVs) with a maximum permissible avionic payload of only a few grams need lightweight, low-power sensors to be able to navigate safely when flying through unknown environments. To meet these demanding specifications, we developed a simple functional model for an Elementary Motion Detector (EMD) circuit based on the common housefly's visual system. During the last two decades, several insect-based visual motion sensors have been designed and implemented on various robots, and considerable improvements have been made in terms of their mass, size and power consumption. The new lightweight visual motion sensor presented here generates 5 simultaneous neighboring measurements of the 1-D angular speed of a natural scene within a measurement range of more than one decade [25 °/s; 350°/s]. Using a new sensory fusion method consisting in computing the median value of the 5 local motion units, we ended up with a more robust, more accurate and more frequently refreshed measurement of the 1-D angular speed

A bio-inspired celestial compass applied to an ant-inspired robot for autonomous navigation

International audienceCommon compass sensors used in outdoor environments are highly disturbed by unpredictable magnetic fields. This paper proposes to get inspiration from the insect navigational strategies to design a celestial compass based on the linear polarization of ultraviolet (UV) skylight. This bio-inspired compass uses only two pixels to determine the solar meridian direction angle. It consists of two UV-light photo-sensors topped with linear polarizers arranged orthogonally to each other as it was observed in insects' Dorsal Rim Area. The compass is embedded on our ant-inspired hexapod walking robot called Hexabot. The performances of the celestial compass under various weather and UV conditions have been investigated. Once embedded onto the robot, the sensor was first used to compensate for yaw random disturbances. We then used the compass to maintain Hexabot's heading direction constant in a straightforward walking task over a flat terrain while being perturbated in yaw by its walking behaviour. Experiments under various meteorological conditions provided steady state heading direction errors from 0.3 • (clear sky) to 1.9 • (overcast sky). These results suggest interesting precision and reliability to make this new optical compass suitable for autonomous field robotics navigation tasks

A bio-inspired celestial compass for a hexapod walking robot in outdoor environment

International audiencePoster de la 13ème Journée de l'Ecole Doctorale 463 du 02/06/2017

A new bio-inspired eye to achieve accurate hovering, positioning and fast tracking

International audienceThis paper presents a new bio-inspired artificial eye composed of only 24 pixels, able to locate accurately a target in its small field of view. The proposed eye is composed of 4 hyperacute minimalist eyes ([l]) which are combined to extends the previous works ([2,3]) to the 2-D localization case. The linearity and the fields of view of the visual sensors were improved thanks to new fusion algorithms and an efficient calibration procedure. The eye, oriented toward the ground, is mounted on a very light custom-made pan-tilt system which makes the eye able to track faithfully and smoothly a moving target. lt is shown here, that such a system can be embedded onto a small quadrotor to achieve accurate positioning with respect to the target. The quadrotor used in this work is an open-source platform which is described in details in [ 4], and algorithms are implemented thanks to a new fast prototyping open-source Matlab/Simulink toolbox [5]. The attitude of the robot is estimated using a complementary filter ([6]) implemented with quaternions and attitude setpoints are tracked using a quaternion based geometric controller ([7]). The positions and translational speeds are estimated using an EKF fusing the visual information. The decoupling system is enhanced with bio-inspired reflexes which stabilize efficiently the gaze of the robot during manoeuvres and disturbances [8,9,10]. The use of very few pixels allow to achieve high refresh-rate of the visual algorithm as fast as 400 Hz. This high refresh rate coupled to a very fast mechanical active decoupling make the aerial robot able to track efficiently a target moving at a speed up to 200°/s , and to achieve rotational speed of 800 °/s during disturbances rejection. Finally, we demonstrated experimentally, that it is possible with such a system to achieve accurate visual hovering and tracking. The positioning and tracking performances of the proposed algorithms were evaluated in a flying arena equipped with a 17 T-40s Vicon cameras, delivering a high reliable ground truth.[1] S. Viollet, Vibrating makes for better seeing: from the fly's micro eye movements tohyperacute visual sensors, Frontiers in Bioengineering and Biotechnology, vol. 2, no. 9, 2014.[2] L. Kerhuel, S. Viollet, and N. Franceschini, The VODKA sensor: A bio-inspired hyperacuteoptical position sensing device, Sensors Journal, IEEE, vol. 12, no. 2, pp. 315-324, Feb 2012[3] R. Juston, L. Kerhuel, N. Franceschini, and S. Viollet, Hyperacute edge and bar detection in abioinspired optical position sensing device, Mechatronics, IEEE/ASME Transactions on, vol. 19,no. 3, pp. 1025-1034, June 2014.[4] A. Manecy, N. Marchand, F. Ruffier, and S. Viollet, X4-MaG: A Low-Cost Open-SourceMicro-Quadrotor and its Linux-Based Controller, International Journal of Micro Air Vehicles(IJM..4. V), Accepted for publication.[5] A. Manecy, N. Marchand and S. Viollet. RT-MaG: an open-source SIMULINK Toolbox forReal-Time Robotic Applications. IEEE International Conference on Robotics and Biomimetics(ROBIO), 2014, Bali, Indonesia,[6] R. Mahony, T. Hamel, J.-M. Pflimlin, (2008). Nonlinear Complementary Filters on theSpecial Orthogonal Group, Automatic Contra[, IEEE Transactions on, 53(5): 1203-1218.[7] T. Lee, M. Leoky, N. McClamroch, Geometric Tracking Control of a Quadrotor UAV onSE(3), Decision and Contra[ (CDC), 2010 49th IEEE Conference on, 2010, pp. 5420- 5425.doi:l0.1109/CDC.2010.5717652 ..[8] A. Manecy, S. Viollet, N. Marchand. Bio-Inspired Hovering Control for an Aerial RobotEquipped with a Decoupled Eye and a Rate Gyro. IEEEIRSJ International Conference onIntelligent Robots and Systems (IROS), 2012, Vilamoura, Algarve, Portugal, pp 1110-1117. doi:10.1109/IROS.2012.6385853[9] A. Manecy, R. Juston, N. Marchand, S. Viollet. Decoupling the Eye: A Key toward a RobustHovering for Sighted Aerial Robots. Advances in Aerospace Guidance, Navigation and Contra[,part III, Springer, 2013, pp 317-336. doi: 10.1007/978-3-642-38253-6_20.[10] A. Manecy, N. Marchand and S. Viollet. Hovering by Gazing: A Novel Strategy forImplementing Saccadic Flight-based Navigation in GPS-denied Environments. Int J Adv RobotSyst, 2014, 11:66. doi: 10.5772/58429

A Novel Hyperacute Gimbal Eye to Implement Precise Hovering and Target Tracking on a Quadrotor

IEEE International Conference on Robotics and Automation (ICRA), Royal Inst Technol, Ctr Autonomous Syst, Stockholm, SWEDEN, MAY 16-21, 2016International audienceThis paper presents a new minimalist bio-inspired artificial eye of only 24 pixels, able to locate accurately a target placed in its small field of view (+/- 10 degrees). The eye is mounted on a very light custom-made gimbal system which makes the eye able to track faithfully a moving target. We have shown, that our gimbal eye can be embedded on a small quadrotor to achieve accurate hovering with respect to a target placed onto the ground. Our aiborne eye was enhanced with a bio-inspired reflex in charge of locking efficiently the robot's gaze onto a target and compensate for the robot's rotations and disturbances. The use of very few pixels allowed to implement a visual processing algorithm at a refresh rate of 400 Hz. This high refresh rate coupled to a very fast control of the eye's orientation allowed the robot to track a target moving at a speed up to 200 degrees.s(-1)

A novel insect-inspired optical compass sensor for a hexapod walking robot

International audienceIn an outdoor autonomous navigational context, classic compass sensors such as magnetometers have to deal with unpredictable magnetic disturbances. In this paper, we propose to get inspiration from the insect navigational abilities to design a celestial compass based on linear polarization of ultraviolet (UV) skylight. To compute the solar meridian relative orientation, our 3D-printed celestial compass uses only two pixels created by two UV-light photo-sensors topped with linear polarizers arranged orthogonally to each other, in the same manner that was observed in insects' Dorsal Rim Area ommatidia. The compass was then embedded on our hexapod walking robot called Hexabot. We first tested the UV-polarized light compass to compensate for yaw random disturbances. We then used the compass to maintain Hexabot's heading direction constant in a straightforward task, knowing the robot has important yaw drifts. Experiments under various meteorological conditions provided steady state heading direction errors from 0.3° under clear sky conditions to 1.9° under overcast sky, which suggests interesting precision and reliability to make this optical compass suitable for robotics

A bio-inspired celestial compass for a hexapod walking robot in outdoor environment

International audienc