A 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 cm3), 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.

Abstract-The X-Morf robot is a 380-g quadrotor consisting of two independent arms each carrying tandem rotors, forming an actuated scissor joint. The X-Morf robot is able to actively change in-flight its X-geometry by changing the angle between its two arms. The magnetic and electrical joint between the quadrotors arms makes them easily removable and resistant to crashes while providing the propellers with sufficient power and ensuring high quality signal transmission during flight. The dynamic model on which the X-Morf robot was based, was also used to design an adaptive controller. A Model Reference Adaptive Control (MRAC) law was implemented to deal with the uncertainties about the inertia and the center of mass due to the quadrotors reconfigurable architecture and for in-flight span-adapting purposes. The tests performed with the X-Morf robot showed that it is able to decrease and increase its span dynamically by up to 28.5% within 0.5s during flight while giving good stability and attitude tracking performances.

Common 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 bioinspired compass uses only two pixels to determine the solar meridian direction angle. It consists of two UV-light photosensors 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.

Abstract-In 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 straight-forward 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.

This 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, 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 bioinspired 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°• s −1 .

Mimosa Pudica rapidly folds leaves when touched. Motion is created by pulvini, ``the plant muscles'' that allow plants to produce various complex motion. Plants rely on local control of the turgor pressure to create on-demand motion. In this paper, the mechanics of a cellular material inspired from pulvinus of Mimosa Pudica is studied. First, the manufacturing process of a cell-controllable material is described. Its deformation behaviour when pressured is tested, focussing on 3 pressure patterns of reference. The deformations are modelled based on the minimisation of elastic energy framework. Depending on pressurisation pattern and magnitude, reversible buckling-induced motion may occur.

There is a growing interest for bio-logging and the measurement of animal or human motion. However, most of the technical solutions are commercial and therefore fit hardly to particular needs. Here, we describe in details an Arduino-based stand-alone logger featuring a 32-bit microcontroller, an IMU, a Bluetooth link and a SD card. Angular speeds and 3D orientations measurements (roll, pitch and yaw angle) of the hydrofoil are done at a sampling frequency of 100 Hz while the kiteboard is moving in the open sea. Software and hardware design are made fully available on an open archive to facilitate the development of such device.

This study concerns the development of an optical compass inspired by the celestial compass of the desert ant Cataglyphis. This bioinspired navigational instrument opens up new opportunities for navigation in the absence of GNSS or GSM coverage for locating outdoors. This pedagogical activity, through the design of the instrument, aims at understand different physical phenomena involved in optical heading detection: Rayleigh scattering of sunlight in the sky, polarization of light and measurement of heading from photosensors. The design and the fabrication of an experimental teaching device are both described. Experiments were performed to allow students (2nd year of master in robotics & IoT) to become familiar with bio-inspired engineering applied to optical heading detection. Students used an Arduino board (8-bit architecture) to address issues related to the real-time processing of microcontroller with limited computational capabilities. Finally, examples of measurements made by students are presented to demonstrate the pedagogical use of such an experimental device for heading measurement in robotics. Our prototype works in the blue visible light and has only 4 photosensors, each one covered with a different orientation of its polarizing filter.