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

Constitutions and Bills of Rights:Invigorating or Placating Democracy?

Champions of constitutions and bills of rights regularly portray them as possessing significant, sometimes mysterious, powers. One characterisation is that newly implemented constitutions may invigorate a democracy, particularly at the ballot box. This paper challenges that notion by scrutinising a relatively unexplored area of constitutional performance: voter turnout. In particular, it examines a number of jurisdictions that have recently implemented constitutions and bill of rights, finding that in many of them, voter turnout decreased after passage, sometimes significantly. As the argument for a codified British constitution endures, the findings of this paper provide provisional evidence that those advocating for such a device should be wary of touting its potentially invigorating democratic effects. Ultimately, however, the paper calls for more research into the area of constitutions and democratic performance, such as voter turnout

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

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