BIOINSPIRED HARDWARE Erki Suurjaak Howdy. My presentation is about bioinspired hardware. It’s not even close to an exhaustive overview, it’s just an introduction to some advancements in the field in recent years. 1
Overview • bioinspired hardware • NASA’s exploration systems • robots Ariel and RHex • future? I will first give a brief introduction to bioinspired hardware. Then I will mainly concentrate on research and advances made by NASA in their search for a superior exploration system. In addition, I will introduce some other bio-inspired hardware, robots like the crab-like Ariel, the cockroach-like RHex. And I’ll try to imagine the future a bit. 2
Bioinspired Hardware • studies processes and • seeks alternative mechanisms in nature hardware design and implementation So, what is bioinspired hardware? Simply put, it’s hardware design copied from the nature. Here people study the processes and mechanisms we can find in nature, some of which are extremely ingenious, and try to apply the design to current hardware, in order to produce superior mechanisms than we humans have come up with. 3
Bioinspired Hardware: Results • biomorphic robots – mostly insectlike • computer vision – navigation – shape recognition • more efficient design for mechanisms – seed pod fliers – adhesive surfaces: beyond velcro This is relatively new field (of course, bioinspired inventions have appeared all the time, but in recent years, the field has seen bigger growth), and so, there are not very many results. However, the results are: - Biomorphic robots: robots that in their structure make use of some biological mechanisms, usually movement. The main inspiration has been drawn from insects, who achieve very much with so little. For example, terrain vehicles that copy crab movement. - Another result is the area of computer vision. Studying biological systems has shown us some very simple and effective devices for navigation in a complex environment, and for shape recognition, tasks that are quite hard to program by hand. - Nature can provide us with additional designs, for example for constructing gliders or fliers mimicking seed pods, or constructing adhesive surfaces vastly superior to velcro, which was also inspired by nature: the inventor came upon the idea when he was picking burrs from the coat of his cat. 4
NASAs Biomorphic Explorers • mobile platforms useful for exploration • Bioinspired Engineering of Exploration Systems (BEES) • idea: many small biomorphic explorer machines Solar System exploration could be substantially enhanced if it were possible to deploy a large number of small, inexpensive, independent, autonomous platforms, each with its own dedicated microsensors, power unit, and communication system into the environment of planetary bodies. The Sojourner rover's success on the surface of Mars has proven beyond doubt that a single mobile platform on a planetary surface, equipped with sensors, can provide a wealth of new science data. The concept of multiple explorers is expected to greatly enhance the science return. Small platforms mimicking the mobility of biological systems, can be built at low cost and made to carry scientific instruments. They can explore sites difficult to reach by traditional platforms. They would complement the abilities of the larger and relatively expensive exploration platforms (e.g. landers, rovers, and aerobots). Movement can vary: they could fly, hover, hop, burrow, or walk, to explore surface, sub-surface and atmosphere. Which makes them pretty versatile. 5
Bee-Inspired Vision & Guidance • amazing results with a handful of neurons • simple and effective hazard avoidance • compound eyes give panoramic vision • simple landing with minimal computation Most flying insects cope remarkably well with their environment, especially considering they have only a tiny fraction of neurons that humans have. In fact, a bee is capable of navigation so far unsurpassed by any human-made and human-controlled flier. Insects use a number of ingenious devices to overcome problems posed by immobile eyes and lack of stereo vision. All flying systems need to have a working obstacle avoidance system, as an in- flight collision can prove fatal. Bees depend on motion vision to achieve terrain following and obstacle avoidance: they simply avoid directions in which image motion appears high. It’s easily possible to implement this in a robot flier, as video cameras with a framerate of more than 500 Hz are small and cheap. There are robust and computationally inexpensive image processing algorithms that can compute motion with a remarkable accuracy. Such a solution is superior to radar or laser or ultrasound vision. The compound eyes that bees have give them panoramic vision that covers almost the entire viewsphere. Compound eyes, for example, make it easy to fly at a certain distance from a canyon wall, by holding the wall’s motion at a constant rate. NASA has developed panoramic imaging systems that can be hooked up to any off-the-shelf video camera. Bees have a very simple landing technique. They hold forward speed proportional to the vertical speed, and the optical flow of the landing surface is held constant. This technique does not require knowledge of current speed or height, and is computationally inexpensive, requiring quite light hardware. 6
Dragonflies See the Horizon • additional eyes ( ocelli ) see a short spectrum • UV and green input combined together • result: correct attitude detected Many insects, like the dragonflies, have additional small eyes on their head, called ocelli. These eyes only see a limited amount of spectrum, like UV and green. They are very useful in determining attitude in respect to the horizon, as they can eliminate false signals caused by a setting sun. For example, take two eyes, one sees UV and the other green. The UV sees a dark ground, a light sky and very bright sun. The green eye sees a uniform picture and a very bright sun. Appropriate processing of the two signals removes the common feature, the sun, and eliminates many effects caused by varying sky color, resulting in a correctly detected attitude. This system is superior to a conventional system of rate gyroscopes: it gives an absolute attitude reference, while gyros accumulate noise. Additionally, it’s very small, light and computationally inexpensive. An equivalent conventional unit would be more than 40 times heavier. 7
BEES: Seed Wing Pod Fliers • plant inspired payload distribution • 20 cm wingspan • load around 60 grams • simpler and smaller than parachutes • slower descent than parachutes • 2x smaller shock on impact than parachutes An additional thing NASA is interested in is deploying a number of fliers or gliders to scout out terrain before landing, and perform atmospheric and surface experiments. For this, inspiration has been drawn from seed pods, namely maple seeds. Maple seed pods use a long light wing and the payload, the seed itself, at the bottom of it. The payload makes up more than 80% of the whole mass. When investigated, NASA found it can develop a small flier with a 20 cm wingspan capable of handling a payload around 60 grams. And this flier or floater is considerably better than using a parachute. It’s simpler, more robust, and smaller, its rate of descent is smaller which allows it more time for observations, and it has a much smaller shock on impact, suffering less damage to equipment. It has unobstructed view overhead. A prototype flier has been developed, which has onboard communications, antennas (in fact, the whole wing area is an antenna, coated with a thin layer of metal), and it has lots of sensors like pressure, temperature, radiation, and IR sensors. In addition, it has equipment for experiments on the surface once it has landed. 8
Other Bio-Inspired Robots: Ariel • movement inspired by crabs • capable of negotiating terrain unaccessible for wheeled machines • capable of underwater movement and resisting wave impact Moving just like a crab, this autonomous robot built by iRobot is the first legged platform capable of walking either on land or underwater in the turbulent surf zone. Able to climb over obstacles and crevices that would block traditional wheeled vehicles, the robot also can resist the impact of waves. Ariel is also completely invertible — if flipped over by the waves, its legs simply reorient so that the "top" of the body becomes the bottom. It is undergoing tests in which it locates mines in the surf zone. 9
The Robot Hexapod RHex • cockroach-inspired • so far, unsurpassed robotic maneuverability • speed up to 3 meters • a possible candidate for Mars 2007 The Robot Hexapod RHex (pronounced "rex") is the most maneuverable robot built, as of last August. It’s about the size of a shoebox. It can bump along at up to 3 meters per second and last close to two hours on one battery charge. Its locomotion is cockroach-inspired, although it does not look like one, which to mind is fortunate. It has six legs, which are capable of clockwise rotation. It’s a possible candidate for the 2007 mission to Mars, which needs surface robots to navigate rough terrain. 10
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