A sighted aerial robot with fast gaze and heading stabilization

International audienceAutonomous guidance of Micro-Air Vehicles (MAVs) in unknown environments is a challenging task because these artificial creatures have small aeromechanical time constants, which make them prone to be disturbed by gusts of wind. Flying insects are subject to quite similar kinds of disturbances, yet they navigate swiftly and deftly. Flying insects display highperformance visuo-motor control systems that have stood the test of time. They can therefore teach us how vision can be used for immediate and vital actions. We built a 50-gram tethered aerial demonstrator, called OSCAR II, which manages to keep its gaze steadily fixating a target (a dark edge), in spite of nasty thumps that we deliberately gave to its body with a custom-made "slapping machine". The robot's agile yaw reactions are based on: - a mechanical decoupling of the eye from the body - an active coupling of the robot's heading with its gaze - a Visual Fixation Reflex (VFR) - a Vestibulo-Ocular Reflex (VOR) - an accurate and fast actuator (Voice Coil Motor, VCM) The actuator is a 2.4-gram voice coil motor that is able to rotate the eye with a rise time as small as 12ms, that is, much shorter than the rise time of human oculo-motor saccades. In connection with a micro-rate gyro, this actuator endows the robot with a high performance "vestibulo ocular reflex" that keeps the gaze locked onto the target whatever perturbations in yaw affect the robot's body. Whenever the robot is destabilized (e.g., by a slap applied on one side), the gaze keeps fixating the target, while being the reference to which the robot's heading is servoed. It then takes the robot only 0:6s to realign its heading with its gaze

Descripción de ley de movimiento de cascarilla plegable no expansible en campo de fuerzas de gravedad

This work makes use of Navier-Stokes equations to describe an analytical method of finding the motion speed of a flexible inextensional shell falling down to the ground from a preset height and determines the duration of this fall. The soft shell in question is a fabric body of aerodynamic shape or an item of clothes, an airborne vehicle element, etc. Analytical relations are presented for the speed at which the shell moves in the air, taking account of the air resistance and the shell fall duration. The boundary problem of the soft shell vertically falling in the air is solved.Aquí se usan las ecuaciones de Navier-Stokes para describir un método analítico de calcular la velocidad del movimiento de una cascarilla plegable no expansible que cae en tierra de una altura predeterminada y calcular la duración de la caída. La cascarilla plegable en cuestión es un objeto  de tejido de configuración aerodinámica o una prenda de vestir, un elemento de un vehículo aéreo, etc. Se presentan las relaciones analíticas para calcular la velocidad con que la cascarilla cae en el aire. Se tienen en cuenta en las fórmulas la resistencia del aire y la duración de la caída. Se resuelve el problema de límites para la cascarilla que cae verticalmente en el aire

Descripción de ley de movimiento de cascarilla plegable no expansible en campo de fuerzas de gravedad

Aquí se usan las ecuaciones de Navier-Stokes para describir un método analítico de calcular la velocidad del movimiento de una cascarilla plegable no expansible que cae en tierra de una altura predeterminada y calcular la duración de la caída. La cascarilla plegable en cuestión es un objeto de tejido de configuración aerodinámica o una prenda de vestir, un elemento de un vehículo aéreo, etc. Se presentan las relaciones analíticas para calcular la velocidad con que la cascarilla cae en el aire. Se tienen en cuenta en las fórmulas la resistencia del aire y la duración de la caída. Se resuelve el problema de límites para la cascarilla que cae verticalmente en el air

Neuromimetic Robots inspired by Insect Vision

International audienceEquipped with a less-than-one-milligram brain, insects fly autonomously in complex environments without resorting to any Radars, Ladars, Sonars or GPS. The knowledge gained during the last decades on insects' sensory-motor abilities and the neuronal substrates involved provides us with a rich source of inspiration for designing tomorrow's self-guided vehicles and micro-vehicles, which are to cope with unforeseen events on the ground, in the air, under water or in space. Insects have been in the business of sensory-motor integration for several 100 millions years and can therefore teach us useful tricks for designing agile autonomous vehicles at various scales. Constructing a "biorobot" first requires exactly formulating the signal processing principles at work in the animal. It gives us, in return, a unique opportunity of checking the soundness and robustness of those principles by bringing them face to face with the real physical world. Here we describe some of the visually-guided terrestrial and aerial robots we have developed on the basis of our biological findings. These robots (Robot Fly, SCANIA, FANIA, OSCAR, OCTAVE and LORA) all react to the optic flow (i.e., the angular speed of the retinal image). Optic flow is sensed onboard the robots by miniature vision sensors called Elementary Motion Detectors (EMDs). The principle of these electro-optical velocity sensors was derived from optical/electrophysiological studies where we recorded the responses of single neurons to optical microstimulation of single photoreceptor cells in a model visual system: the fly's compound eye. Optic flow based sensors rely solely on contrast provided by reflected (or scattered) sunlight from any kind of celestial bodies in a given spectral range. These nonemissive, powerlean sensors offer potential applications to manned or unmanned aircraft. Applications can also be envisaged to spacecraft, from robotic landers and rovers to asteroid explorers or space station dockers, with interesting prospects as regards reduction in weight and consumption

Field Programmable Gate Array (FPGA) for Bio-Inspired Visuo-Motor Control Systems Applied to Micro-Air Vehicles

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Optic Flow Based Visual Guidance: From Flying Insects to Miniature Aerial Vehicles

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Insect inspired visual motion sensing and flying robots

International audienceFlying insects excellently master visual motion sensing techniques. They use dedicated motion processing circuits at a low energy and computational costs. Thanks to observations obtained on insect visual guidance, we developed visual motion sensors and bio-inspired autopilots dedicated to flying robots. Optic flow-based visuomotor control systems have been implemented on an increasingly large number of sighted autonomous robots. In this chapter, we present how we designed and constructed local motion sensors and how we implemented bio-inspired visual guidance scheme on-board several micro-aerial vehicles. An hyperacurate sensor in which retinal micro-scanning movements are performed via a small piezo-bender actuator was mounted onto a miniature aerial robot. The OSCAR II robot is able to track a moving target accurately by exploiting the microscan-ning movement imposed to its eye's retina. We also present two interdependent control schemes driving the eye in robot angular position and the robot's body angular position with respect to a visual target but without any knowledge of the robot's orientation in the global frame. This "steering-by-gazing" control strategy, which is implemented on this lightweight (100 g) miniature sighted aerial robot, demonstrates the effectiveness of this biomimetic visual/inertial heading control strategy

Aerial Vehicles

This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space