Biomimetics - Biologically Inspired Technologies - Yoseph Bar Cohen Episode 1 Part 2 ppt

as the ground or plants. Other creatures that perform worm-like movement but in a different way can be seen in the earthworm, maggot, hornworm, ragworm (swimming, walking, burrowing), eel, geometrid larva, snake, millipede, and centipede. 1.5.2.3 Pumping Mechanisms Nature uses various pumping mechanisms that are also used in mechanical pumps. The lungs pump air in and out (tidal pumping) via the use of the diaphragm to enable our breathing. Peristaltic pumping is one of the most common forms of pumping in biological systems, where liquids are 1. Clamps Brake no. 1 2. Extends and moves Brake no. 2 3. Clamps Brake no. 2 4. Retracts and moves Brake no. 1 forward Extender Brake no. 1 Brake no. 2 Shaft Figure 1.6 Operation sequence of a typical inchworm mechanism. Brings the back forward Stretches forward Brings the back forward Figure 1.7 One of the forms of mobility seen in worms (the millipede). Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 12 21.9.2005 6:40pm 12 Biomimetics: Biologically Inspired Technologies squeezed in the required direction. Such pumping is common in the digestion system. Pumping via valves and chambers that change volume is found in human and animal hearts, with expansion and contraction of chambers. The use of one-way valves is the key to the blood flow inside the veins, where the pressure is lower. 1.5.2.4 Controlled Adhesion Controlled adhesion is achieved by many organisms using a highly fibrillated microstructure. The Hemisphaerota cyanea (a beetle) uses wet adhesion that is based on capillary intera ction (wet adhesion) (Eismer and Aneshansly, 2000). The gecko exhibits remarkable dry adhesion using van der Waals forces. Even though these forces provide low intrinsic energy of approximately 50 mJ/m 2 , their effective localized application allows for the remarkable capability (Autumn et al., 2002). Using this adhesion mechanism, the gecko can race up a polished glass at a speed of approximately 1 m/sec and support its body weight from a wall with a single toe. Geckos have millions of 10 to 20 mm long setae, which are microscopic hairs at the bottom of their feet. Each seta ends with about 1000 pads at the tip (called spatulae) that significantly increase the surface density, and allow getting into close contact with the adhered surface. This capability motivated efforts to mimic the gecko adhesion mechanism, and some limited success was reported. Re- searchers like Autumn and Peattie (2003) sought to develop artificial foot-hair tip model for a dry, self-cleaning adhesive that works under water and in a vacuum. Their limited success effectively created a synt hetic gecko adhesive that can potentially operate in vacuum areas of clean rooms as well as outer space. 1.5.2.5 Biological Clock The body processes are controlled by our biological clock and it is amazing in its precision. It is critical in assuring the timely execution of the genetic code to form the same characteristics for the given creatures at the same seque nce of occurrence at about the same age. The cicada matures for 17 years, after which it lives for another 1-week period. During this week, all cicadas mate, the females lay eggs, and then they all die. The hatched cicadas then develop for another 17 years and these synchronized processes are repeated again. 1.5.3 Biologically Inspired Structures and Parts Parts and structures also have a biological model of inspiration. Some of these are discussed below. 1.5.3.1 Honeycomb as a Strong, Lightweight Structure Honeycombs consist of perfect hexagonal cellular structures and they offer optim al packing shape. For the honeybees, the geometry meets their need for making a structure that provides the maximum amo unt of stable containment (honey, larvae) using the minimum amount of material (Figure 1.8). The honeycomb is, for the same reasons, an ideal structure for the construction of control surfaces of an aircraft and it can be found in the wing, elevators, tail, the floor, and many other parts that need strength and large dimensions while maintaining low weight. An example of a control surface part of an aircraft with a honeycomb is shown in Figure 1.9. 1.5.3.2 Hand Fan Historically, hand fans were one of the most important ways of cooling down during the hot summer months (Figure 1.10). This simple tool used to be made of feathers, which copy the shape Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 13 21.9.2005 6:40pm Introduction to Biomimetics 13 Figure 1.8 The honeycomb (left) and the nest of the wasp (right) are highly effective structures in terms of low weight and high strength. Figure 1.9 A cross-section of a honeycomb structure that plays an important role in the construction of aircraft control surfaces. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 14 21.9.2005 6:40pm 14 Biomimetics: Biologically Inspired Technologies of a bird’s wing or the tail of the male peacock. The advantage of using feathers is their lightweight structure and their beauty. 1.5.3.3 Fishing Nets and Screens The fishing net is another of nature’s invention that most likely has been imitated by humans after observing the spider’s use of its web to catch flies. At an even more basic level, the concept of fiber or string may well have been inspired by the spider. Both the spider web and the fishing net have structural similarities and carry out the same function of trapping creatures passing by. The spider uses a sticky material that helps capture the trapped insects by gluing them onto the web, and the spider knows how to avoid being glued to its own web. Depending on the type of spider, the distance between the fibers in the web can be as large as several centimeters and as small as fractions of a millimeter. Beside the use of nets to catch fish, insects, and animals, humans further expanded the application of the concept of the net to such tools as bags for carrying and storage of objects, protective covers against insects, and mounting stored food while allowing aeration. The screen, mesh, and many other sieving devices that allow separation of various size objects may also be attributed to the evolution of the net. Also, it is possible to attribute the invention of the net configuration to many medical supplies including the bandage and the membranes that are used to cover burns and other wounds. 1.5.3.4 Fins Unlike the failure to fly by copying the flapping of birds’ wings, the use of fins to enhance swimming and diving has been highly successful. While it may be arguable whether the fins were a direct biologically inspired invention, it is common knowledge that swimming creatures have legs with gossamer (geese, swans, seagulls, seals, frogs, etc.). Imitating the legs of these creatures offered the inventors of the fins a model that was improved to the point where it resembles Figure 1.10 The hand fan, which is also produced in a folding form, was probably inspired by the peacock tail and the ability of this bird to open its tail into a wide screen that is shaken to impress the female. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 15 21.9.2005 6:40pm Introduction to Biomimetics 15 the leg of the seal and to a lesser extent that of the frog. This similarity to the latter led to the naming of divers — frogmen, which is clearly a biomimetically inspired name. 1.5.4 Defense and Attack Mechanisms in Biology A critical aspect of the survival of various species is having effective defense and attack mechan- isms to protect against predators, catch prey, secure mating, protect the younger generation, procure and protect food, and other elements that are essential to survival. The following are some of the biologically inspired mechanisms that were adapted by humans. Further details are discussed more extensively in Chapter 13. 1.5.4.1 Camouflage The chameleon and the octopus are well known for their capability of changing their body color. The octopus matches the shape and texture of its surroundings as well as releases ink to completely mask its location and activity — and yet, the octopus is a color-blind creature (Hanlon et al., 1999). Another aspect of the octopus’ behavior is its ability to configure its body to allow traveling through narrow openings and passages. These include tubes, which are significantly smaller than its normal body cross- section. Generally, camouflage is not used solely for concealment alone, it also allows the predator to get close to its prey before charging ahead and capturing it by gaining the element of surprise while minimizing the response time of the prey. In some creatures, camouflage provides deterrence. For instance, some snakes, which are harmless, clone the appearance of highly poisonous snakes. Further, some harmless flies camouflage themselves with bright colors, pretending that they are wasps. Minutes after birth, a baby deer is already capable of recognizing danger and taking action of passive self-defense. Since oftentimes the baby deer is left alone after birth, while the mother goes off to search for food, the baby has to rely on its ability to hide. It does this by finding shelter and taking advantage of basic camouflage rules. Without training, it is able to recogniz e which animals pose a threat to its life. Furthermore, the baby deer is equipped with the basic skill of taking advantage of objects in its terrain (e.g., plants), to reduce its body profile by ducking low, and to use a surrounding background that matches its colors in order to minimize its visibility. These skills, which are innate in the baby deer, are taught in human military training as camouflage methods. While itis impossible for humans to imitate theoctopus’ ability to squeeze its body through narrow openings (since we have bones and the octopus does not), its camouflage capabilities have been the subject of imitation by all armies. In World War II,the zoologist Hugh Cott (1938) was instrumental in guiding the British army in developing camouflage techniques. Modern military uniforms and weapons are all colored in a way that makes them minimally visible by matching the background colors inthe area where the personnel operate.Further, likethe useof the ink by the octopus, soldiers in the army and on large naval vessels at sea use a smoke screen when they do not want to be seen. Until recently, camouflage has beenused inthe form of fixed colors for uniforms, armor and various military vehicles. With advancement in technology, the possibility of using paint that changes color is becoming increasingly feasible, and the use of liquid crystal color displays as a form of external coating are under consideration for active camouflage. Recent efforts are producing colors that can be changed to adapt to the local terrain (http://www.csmonitor.com/2004/0108/p14s01 -stct.htm). 1.5.4.2 Body Armor The shell is another means of protect ion that some creatures are equipped with, both on Earth and under water, and to a certain extent also in some flying insects. Creatures with body armor include the turtle, snail, and various shelled marine creatures (e.g., mussel, etc.). There are several forms of shells ranging from shelte r that is carried on the back (e.g., snails) to those with full body cover in Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 16 21.9.2005 6:40pm 16 Biomimetics: Biologically Inspired Technologies which creatures can completely close the shell as a means of defense against predators. While the snail is able to emerge from its shell and crawl as it carries the shell on the back (Figure 1.11), the turtle lives inside its ‘‘body armor’’ and is able to use its legs for mobility when it is safe and hide its legs and head when it fears danger. The turtle was probably a good model for human imitation in terms of self-defense. The idea of body protection was adapted by humans many thousands of years ago in the form of hand-carried shields that allowed for defense against sharp objects, such as knives and swords. As the capability to process metals improved, humans developed better weapons to overcome the shield and therefore forced the need for better body armor in order to provide cover for the whole body. The armor that knights wore for defense during the Middle Ages provided metal shield from head to toe. Figure 1.12 shows such an armor for the upper part of the body. In Japan, a more flexible armor was produc ed that consisted of thin metal strips connected with flexible leather bands. Relying on such protection led to defeat when faced against soldiers with rifles. As weapon technology in the West evolved, efforts were made to reduce the use of armor on individual soldiers for the sake of increased speed and maneuverability, as well as to lower the cost of fabrication and operation. In parallel, armored vehicles, which included tanks providing mobile shield and weaponry, with both defense and offense capabilities were developed. In nature, the use of shell for body protection is limited mostly to slow moving creatures and nearly all of them are plant-eaters. 1.5.4.3 Hooks, Pins, Sting, Syringe, Barb, and the Spear Most of us have experienced at least once in our lifetime the pain of being hurt by a prick from plants — sometimes from something as popular and beautiful as the rose bush. Such experience can Figure 1.11 The snail protects its soft body with a hard-shell which it carries on its back when safe. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 17 21.9.2005 6:40pm Introduction to Biomimetics 17 also occur when interacting with certain creatures, such as the bee. In the case of the bee, the stinger is left in the penetrated area and does not come out because of its spear shape. Humans adapted and evolved the concept of sharp penetrators in order to create many tools for applications in medicine, sports, and weaponry. These tools include the syringe, spears, fishing hooks, stings, barbs, and many others. Once penetrated, the hook and barb section on the head of a harpoon or an arrow makes it difficult to remove the weapon from the body of fish, animal, or hu man being. 1.5.4.4 Decoy The use of decoy is as ancient as the lizard’s use of its tail as a method to distract the attention of predators. The lizard autotomizes its tail and the tail moves rapidly, diverting the attention of the suspected predator while the lizard escapes to safety. This method is quite critical to lizard’s survival and the tail grows back again without leaving a scar. This capability is not only a great Figure 1.12 An armor used as a body protection for knights can be viewed as mimicking the turtle’s hard-shell body cover. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 18 21.9.2005 6:40pm 18 Biomimetics: Biologically Inspired Technologies model for military strategies but also offers a model for potential healing of maimed parts of the human body. Success in adapting this capability could help people with disabilities the possibility of regrowing amputated or maimed parts of their body. 1.5.5 Artificial Organs It is increasingly common to augment body organs with artificial substitutes. This is the result of significant advances in materials that are biocompatible, powerful electronics, and efficient mini- ature actuators. An artificial hand is shown in Figure 1.13 where a mechanism was designed to allow control of the fingers using a hand that matches the appearance of a human real hand. Artificial organs already include the heart, lung, kidney, liver, hip, and others (Chapter 18). Smart limbs, also known as Cyborgs, are also increasingly being developed with various degrees of sophistication and operation similar to the biological model. Moreover, the possibility of an artificial vision allowing a blind person to see is another growing reality, and a description of the state of the art as well as the expected future of this technology is provided in Chapter 17. 1.6 MATERIALS AND PROCESSES IN BIOLOGY The body is a chemical laboratory that processes chemicals acquired from nature and turns them to energy, construction materials, waste, and various multifunctional structures (Mann, 1995). Natural materials have been well recognized by humans as sourc es of food, clothing, comfort, and so on. These include fur, leather, honey, wax, milk, and silk (see Chapte r 14). Even though some of the creatures and insects that produce materials are relatively small, they can produce quantities of materials that are sufficien t to meet human consumption on a scale of mass production (e.g., honey, silk, and wool). The use of natural materials can be traced back to thousands of years. Silk, which is produced to protect the cocoon of the silkmoth, has great properties that include beauty, strength, and durability. These advantages are well recognized by humans and the need to make them in any desired quantity has led to the production of artificial versions and imitations. Some of the fascinating capabilities of natural mater ials include self-healing, self-replication, reconfigurability, chemical balance, and multifunctionality. Many man-made materials are processed by heating and Figure 1.13 A mechanical hand for use as a prosthetic. (Photographed by the author at the Smithsonian Museum in Washington, DC.) Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 19 21.9.2005 6:40pm Introduction to Biomimetics 19 pressurizing, and this is in contrast to nature which uses amb ient conditions. Materials, such as bone, collagen, or silk, are made inside the organism’s body without the harsh treatment that is used to make our materials. The fabrication of biologically derived materials produces minimum waste and no pollution, where the result is biodegradable, and can be recy cled by nature. Learning how to process such materials can make our material choices grea ter, and improve our ability to create recyclable materials that can better protect the environment. There are also studies that are improving prosthetics, which include hips, teeth, structural support of bones, and others. A brief description of structural materials that are made by certain insects and birds is given in this section, whereas Chapters 12 and 14 cover in greater detail the topics of biological materials and their multifunctional characteristics. 1.6.1 Spider Web — Strong Fibers One of biology’s best ‘‘manufacturing engineers’’ with an incredibly effective material-fabrication capability is the spider. It fabricates the web (Figure 1.14) to make a very strong, insoluble, continuous lightweight fiber, and the web is resistant to rain, wind, and sunlight. It is made of very fine fibers that are barely visible allowing it to serve its function as an insect trap. The web can carry significant amount of water droplets from fog, dew, or rain thus making it visible as shown in Figure 1.14. The web structure in the photograph has quite an interesting geometry. It reveals the Figure 1.14 (See color insert) The spider constructs an amazing web made of silk material that for a given weight is five times stronger than steel. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 20 21.9.2005 6:40pm 20 Biomimetics: Biologically Inspired Technologies spokes, the length, and density of sticky spiral material for catching bugs. The segments of the photographed web are normally straight, but are seen curved in this figure due to the weight of the accumulated droplets. The net is sufficiently strong to survive this increased load without collapsing. The spider generates the fiber while at the same time hanging on to it as it emerges cured and flawless from its body. The web is generated at room temperature and at atmospheric pressure. The spider has sufficient supply of raw materials for its silk to span great distances. It is common to see webs spun in various shapes (including flat) between distant trees, and the web is amazingly large compared to the size of the spider. Another interesting aspect of the spider web is the fact that it is a sticky material intended to catch prey, but the spider itself is able to move freely on it without being trapped. The silk that is produced by a spider is far superior in toughness and elasticity to Kevlar 1 , which is widely used as one of the leading materials in bullet proof vests, aerospace structures, and other applications where there is a need for strong lightweight fibers. Though produced in water, at room temperature and pressure, spid er’s silk is much stronger than steel. The tensile strength of the radial threads of spider silk is 1154 MPa, while steel is 400 MPa (Vogel, 2003). Spiders eat flies and digest them to produce the silk that comes out from their back ends, and spool the silk as it is produced while preparing a web for trapping insects. This web is designed to catch insects that cross the net and get stuck due to its stickiness and complexity. While the net is effective in catchi ng insects, the spider is able to maneuver on it witho ut the risk of being caught in its own trap. Recent progress in nano-technology reveals a promise for making fibers that are fine, continuous, and enormously strong. For this purpose, an electrospinning technique was developed (Dzenis, 2004) that allows producing 2-mm diameter fibers from polymer solutions and melts in high electric fields. The resulting nano-fibers were found to be relatively uniform without requiring extensive purification. 1.6.2 Honeybee as a Multiple Materials Producer Another ‘‘material manufacturing engineer’’ found in nature is the honeybee. This insect can make materials in volumes that far exceed the individual bee’s size. Bees are well known for making honey from the nectar that they collect from flowers. They also produce honeycomb from wax. Historically, candles were made using this beeswax, but with the advent of the petroleum industry, candles are now mostly mad e from paraffin wax. Another aspect of honeybee is that their bodies produce a poison that causes great pain, which is injected, through a stinger, into the body of any intruder who is perceived as a threat to the bee’s colony. 1.6.3 Swallow as a Clay and Composite Materials Producer The swallow makes its nest from mud and its own spit forming a composite structure that is strong. The nest is shaped to fit the area onto which it is built. The swallow builds its nest under roofs and other shelters that provide both protection and concealment. Figure 1.15 is a photograph of two nests of swallow. A flock of swallows have gathered next to the nests. While the two nests are different in shape they have similar characteristics and they both provided sufficient room for the chicks to hatch and reach maturity. It is interesting to note that the birds in the photograph attach themselves to the wall carrying their body weight on their claws, which secure them comfortably to the stucco paint on the wall. 1.6.4 Fluorescence Materials in Fireflies and Road Signs Fluorescence materials can be found in quite a few living species and these visible light-emitting materials can be divided into two types: Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 21 21.9.2005 6:40pm Introduction to Biomimetics 21 [...]... Washington, Vol PM136 (March 20 04), pp 1 765 Bar- Cohen Y and B Joffe, ‘‘Magnetically Attached Multifunction Maintenance Rover (MAGMER),’’ NTR, Docket 20 229 , Item No 9854, February 6, 19 97 Bar- Cohen Y and C Breazeal (Eds), Biologically- Inspired Intelligent Robots, ISBN 0-8 19 4-4 87 2- 9 , SPIE Press, Bellingham, Washington, Vol PM 122 (May 20 03), pp 1 393 Bar- Cohen Y and S Sherrit, ‘‘Self-Mountable and Extractable... 16 (19 98), pp 25 0 25 8 Dzenis Y., ‘‘Spinning continuous fibers for nanotechnology,’’ Science, Vol 304 (25 June 20 04), pp 19 17– 19 19 Eismer T and D.J Aneshansly, PNAS, Vol 97, No 12 (20 00), pp 6568–6573 Fisch A., C Mavroidis, Y Bar- Cohen, and J Melli-Huber, ‘‘Haptic and telepresence robotics,’’ Chapter 4, in Bar- Cohen, Y and C Breazeal (Eds), Biologically- Inspired Intelligent Robots, ISBN 0-8 19 4-4 87 2- 9 ,... ISBN 0-8 19 4-4 054-X, SPIE Press, Bellingham, Washington, Vol PM98 (March 20 01) , pp 1 6 71 Bar- Cohen Y., ‘‘Emerging NDE technologies and challenges at the beginning of the 3rd millennium — part II,’’ Material Evaluation, Vol 58, No 2 (February 20 00), pp 14 1 15 0 Bar- Cohen Y., Electroactive Polymer (EAP) Actuators as Artificial Muscles — Reality, Potential and Challenges, 2nd Edition, ISBN 0-8 19 4-5 29 7 -1 , SPIE... ISBN 00 722 26 013 , McGraw-Hill, Osborne (20 02) , http://www.natur.cuni.cz/~vpetr/ Develop.htm Hughes H.C., Sensory Exotica A World Beyond Human Experience, ISBN 0 -2 6 2- 0 827 9-9 , MIT Press, Cambridge, Massachusetts (19 99), pp 1 359 Koza J.R., Genetic Programming: On the Programming of Computers by Means of Natural Selection, ISBN 0 -2 6 2 -1 11 7 0-5 , MIT Press, Cambridge, Massachusetts (19 92) , pp 1 40 Krantz-Ruckler... chemically sensitive, carbon black-polymer resistors,’’ Chemical Materials, Vol 8 (19 96), p 22 98 Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 01 Final Proof page 39 Introduction to Biomimetics 21 . 9 .20 05 6:40pm 39 Lowman P., Long Way East of Eden: Could God Explain the Mess We’re In? ISBN: 18 422 710 83, Paternoster Press, Milton Keynes, UK (20 02) , pp 1 390 Luger G.F., Artificial Intelligence:... http://xxx.infidels.org/~meta/getalife/life.html Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 02 Final Proof page 41 21 . 9 .20 05 11 :39am 2 Biological Mechanisms as Models for Mimicking: Sarcomere Design, Arrangement and Muscle Function Kenneth Meijer, Juan C Moreno, and Hans H.C.M Savelberg CONTENTS 2 .1 Introduction 41 2. 2 Muscle Function 43 2. 3 The Functional Units 44 2. 3 .1. .. Docket No 3 02 91 (July 17 , 20 01) , U.S Patent application No 10 /304 ,19 2, filed on November 27 , 20 03 Bar- Cohen Y., S Sherrit, B Dolgin, T Peterson, D Pal, and J Kroh, ‘‘Ultrasonic/sonic driller/corer (USDC) with integrated sensors,’’ NTR, August 30, 19 99, Item No 0448b, Docket No 20 856, November 17 (19 99) NASA Tech Briefs, Vol 25 , No 1 (January 20 01) , pp 38–39 Patent registration numbers US 10 /25 8007, submitted... artificial haircell using surface micromachining and 3D assembly,’’ The 12 th International Conference on Solid-State Sensors, Actuators and Microsystems, Vol 2, Boston, Massachusetts, June 8 12 , 20 03a Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 01 Final Proof page 38 38 21 . 9 .20 05 6:40pm Biomimetics: Biologically Inspired Technologies Chen J., Z Fan, J Engel, and C Liu, ‘‘Towards modular.. .Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 01 Final Proof page 22 22 21 . 9 .20 05 6:40pm Biomimetics: Biologically Inspired Technologies Figure 1. 15 A group of swallows gathering next to two nests that are made of a composite mix of mud and straws These nests were built under the author’s roof (July 20 04) (a) (b) bioluminescence — a voluntary... results from the rigidity of the widely used gauges Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 01 Final Proof page 25 21 . 9 .20 05 6:40pm Introduction to Biomimetics 25 1. 7 .2 MEMS-Based Flow Detector Mimicking Hair Cells with Cilium On the micron-scale level the monitoring of air (Friedel and Barth, 19 97) and water flow (Bond, 19 96) in insects and in fish is by clusters of hair . used gauges. Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 01 Final Proof page 24 21 . 9 .20 05 6:40pm 24 Biomimetics: Biologically Inspired Technologies 1. 7 .2 MEMS-Based Flow. array (Bartlett and Gardner , Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 01 Final Proof page 26 21 . 9 .20 05 6:40pm 26 Biomimetics: Biologically Inspired Technologies 19 99;. forward Figure 1. 7 One of the forms of mobility seen in worms (the millipede). Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK 316 3_c0 01 Final Proof page 12 21 . 9 .20 05 6:40pm 12 Biomimetics: Biologically