Bio-inspired Landing Approaches and Their Potential Use On Extraterrestrial Bodies

International audienceAutomatic landing on extraterrestrial bodies is still a challenging and hazardous task. Here we propose a new type of autopilot designed to solve landing problems, which is based on neurophysiological, behavioral, and biorobotic findings on flying insects. Flying insects excel in optic flow sensing techniques and cope with highly parallel data at a low energy and computational cost using lightweight dedicated motion processing circuits. In the first part of this paper, we present our biomimetic approach in the context of a lunar landing scenario, assuming a 2-degree-of-freedom spacecraft approaching the moon, which is simulated with the PANGU software. The autopilot we propose relies only on optic flow (OF) and inertial measurements, and aims at regulating the OF generated during the landing approach, by means of a feedback control system whose sensor is an OF sensor. We put forward an estimation method based on a two-sensor setup to accurately estimate the orientation of the lander's velocity vector, which is mandatory to control the lander's pitch in a near optimal way with respect to the fuel consumption. In the second part, we present a lightweight Visual Motion Sensor (VMS) which draws on the results of neurophysiological studies on the insect visual system. The VMS was able to perform local 1-D angular speed measurements in the range 1.5°/s - 25°/s. The sensor was mounted on an 80 kg unmanned helicopter and test-flown outdoors over various fields. The OF measured onboard was shown to match the ground-truth optic flow despite the dramatic disturbances and vibrations experienced by the sensor

Optic Flow-Based Nonlinear Control and Sub-optimal Guidance for Lunar Landing

International audience— A sub-optimal guidance and nonlinear control scheme based on Optic Flow (OF) cues ensuring soft lunar land-ing using two minimalistic bio-inspired visual motion sensors is presented here. Unlike most previous approaches, which rely on state estimation techniques and multiple sensor fusion methods, the guidance and control strategy presented here is based on the sole knowledge of a minimum sensor suite (including OF sensors and an IMU). Two different tasks are addressed in this paper: the first one focuses on the computation of an optimal trajectory and the associated control sequences, and the second one focuses on the design and theoretical stability analysis of the closed loop using only OF and IMU measurements as feedback information. Simulations performed on a lunar landing scenario confirm the excellent performances and the robustness to initial uncertainties of the present guidance and control strategy

Toward an Autonomous Lunar Landing Based on Low-Speed Optic Flow Sensors

International audienceFor the last few decades, growing interest has returned to the quite chal-lenging task of the autonomous lunar landing. Soft landing of payloads on the lu-nar surface requires the development of new means of ensuring safe descent with strong final conditions and aerospace-related constraints in terms of mass, cost and computational resources. In this paper, a two-phase approach is presented: first a biomimetic method inspired from the neuronal and sensory system of flying insects is presented as a solution to perform safe lunar landing. In order to design an au-topilot relying only on optic flow (OF) and inertial measurements, an estimation method based on a two-sensor setup is introduced: these sensors allow us to accu-rately estimate the orientation of the velocity vector which is mandatory to control the lander's pitch in a quasi-optimal way with respect to the fuel consumption. Sec-ondly a new low-speed Visual Motion Sensor (VMS) inspired by insects' visual systems performing local angular 1-D speed measurements ranging from 1.5 • /s to 25 • /s and weighing only 2.8 g is presented. It was tested under free-flying outdoor conditions over various fields onboard an 80 kg unmanned helicopter. These pre-liminary results show that the optic flow measured despite the complex disturbances encountered closely matched the ground-truth optic flow

DE L'INSECTE AUX ROBOTS : OBSERVER, RECONSTRUIRE, INNOVER ET MIEUX COMPRENDRE

Les insectes ailés ont résolu des problèmes ardus tels que la stabilisation du vol, l’évitement d’obstacles en 3D, la poursuite de cibles, l’odométrie, l’atterrissage sans piste aménagée et l’atterrissage sur des cibles en mouvements, problèmes sur lesquels bute encore la robotique autonome contemporaine. Certains principes naturels, éprouvés depuis des millions d’années, peuvent aujourd’hui apporter à la Robotique des idées innovantes. Nous savons depuis 70 ans que les insectes ailés réagissent visuellement aux mouvements relatifs du sol causés par leur mouvement propre [Kennedy, 1939]. De façon surprenante, cet indice visuel naturel, plus récemment nommé “flux optique" [Gibson, 1950], n’a pas encore envahi le champ de l’aéronautique, alors même que les capteurs et les traitements mis en oeuvre par le système nerveux d’un insecte au service de son comportement visuo-moteur commencent à être clairement identifiés [Kennedy, 1951; Reichardt, 1969; Hausen, 1984; Pichon et al., 1989; Franceschini et al., 1989; Collett et al., 1993; Srinivasan et al., 1996, 2000;Serres et al., 2008b; Portelli et al., 2010a].Accorder une certaine autorité de vol à un micro-aéronef est une tâche particulièrement difficile, en particulier pendant le décollage, l’atterrissage, ou en présence de vent. Construire un aéronef de quelques grammes ou dizaines de grammes équipé d’un pilote automatique demande alors une démarche innovante. J’ai donc choisi une démarche bioinspirée résolument tournée vers les insectes ailés pour tenter de résoudre les problèmes inhérents au décollage, au contrôle de la vitesse, à l’évitement d’obstacles, à la réaction au vent, ou bien encore l’atterrissage grâce à lamesure du flux optique

A two-directional 1-gram visual motion sensor inspired by the fly's eye

International audienceOptic flow based autopilots for Micro-Aerial Vehicles (MAVs) need lightweight, low-power sensors to be able to fly safely through unknown environments. The new tiny 6-pixel visual motion sensor presented here meets these demanding requirements in term of its mass, size and power consumption. This 1-gram, low-power, fly-inspired sensor accurately gauges the visual motion using only this 6-pixel array with two different panoramas and illuminance conditions. The new visual motion sensor's output results from a smart combination of the information collected by several 2-pixel Local Motion Sensors (LMSs), based on the \enquote{time of travel} scheme originally inspired by the common housefly's Elementary Motion Detector (EMD) neurons. The proposed sensory fusion method enables the new visual sensor to measure the visual angular speed and determine the main direction of the visual motion without any prior knowledge. By computing the median value of the output from several LMSs, we also ended up with a more robust, more accurate and more frequently refreshed measurement of the 1-D angular speed

Evidence for ventral optic flow regulation in honeybees

To better grasp the visuomotor control system underlying insects' height and speed control, we attempted to interfere with this system by producing a major perturbation on the free flying insect and obsering the effect of this perturbation. Honeybees were trained to fly along a high-roofed tunnel, part of which was equipped with a moving floor. The bees followed the stationary part of the floor at a given height. On encountering the moving part of the floor, which moved in the same direction as their flight, honeybees descended and flew at a lower height. In so doing, bees gradually restored their ventral optic flow (OF) to a similar value to that they had perceived when flying over the stationary part of the floor. OF restoration therefore relied on lowering the groundheight rather than increasing the groundspeed. This result can be accounted for by the control system called an optic flow regulator that we proposed in previous studies. This visuo-motor control scheme explains how honeybees can navigate safely along tunnels on the sole basis of OF measurements, without any need to measure either their speed or the clearance from the ground, the roof or the surrounding walls

Honeybees' Speed Depends on Dorsal as Well as Lateral, Ventral and Frontal Optic Flows

Flying insects use the optic flow to navigate safely in unfamiliar environments, especially by adjusting their speed and their clearance from surrounding objects. It has not yet been established, however, which specific parts of the optical flow field insects use to control their speed. With a view to answering this question, freely flying honeybees were trained to fly along a specially designed tunnel including two successive tapering parts: the first part was tapered in the vertical plane and the second one, in the horizontal plane. The honeybees were found to adjust their speed on the basis of the optic flow they perceived not only in the lateral and ventral parts of their visual field, but also in the dorsal part. More specifically, the honeybees' speed varied monotonically, depending on the minimum cross-section of the tunnel, regardless of whether the narrowing occurred in the horizontal or vertical plane. The honeybees' speed decreased or increased whenever the minimum cross-section decreased or increased. In other words, the larger sum of the two opposite optic flows in the horizontal and vertical planes was kept practically constant thanks to the speed control performed by the honeybees upon encountering a narrowing of the tunnel. The previously described ALIS (“AutopiLot using an Insect-based vision System”) model nicely matches the present behavioral findings. The ALIS model is based on a feedback control scheme that explains how honeybees may keep their speed proportional to the minimum local cross-section of a tunnel, based solely on optic flow processing, without any need for speedometers or rangefinders. The present behavioral findings suggest how flying insects may succeed in adjusting their speed in their complex foraging environments, while at the same time adjusting their distance not only from lateral and ventral objects but also from those located in their dorsal visual field

3rd International Workshop on Instrumentation for Planetary Missions : October 24–27, 2016, Pasadena, California

The purpose of this workshop is to provide a forum for collaboration, exchange of ideas and information, and discussions in the area of the instruments, subsystems, and other payload-related technologies needed to address planetary science questions. The agenda will compose a broad survey of the current state-of-the-art and emerging capabilities in instrumentation available for future planetary missions.Universities Space Research Association (USRA); Lunar and Planetary Institute (LPI); Jet Propulsion Laboratory (JPL)Conveners: Sabrina Feldman, Jet Propulsion Laboratory, David Beaty, Jet Propulsion Laboratory ; Science Organizing Committee: Carlton Allen, Johnson Space Center (retired) [and 12 others