All three papers have been accepted with minor alterations!

BACKGROUND

This is a consolidation of the three papers published in the Springer-Open journal, “The Journal of Robotics and Biomimetics” in a special issue on nano-/micro-robotics under the following titles:

1. A biomimetic study of natural attachment mechanisms— Arctium minus Part 1 [1]

2. A biomimetic study of natural attachment mechanisms: imaging cellulose and chitin Part 2 [2]

3. Micro-design using frictional, hooked, attachment mechanisms: a biomimetic study of natural attachment mechanisms—Part 3 [3]

Frankly the engineer in the researcher took a biology Ph.D. and under the auspices of researching attachment mechanisms, he researched micro-design. This is not least because the only method available to him for shape acquisition at that time to assess mechanical properties was 2-D digitising which his own work for his Master’s thesis in mechanical engineering had suggested was inadequate for that time (2001/2).

The title of part 3 above displays the underlying hypothesis behind the exploration of the detail of papers 1 and 2. It accepts the viability of using cladistic methods to arrive at a scenario where a structure that has survived the “evolutionary sieve” is selected, to quote Nicklaus et al [4], over the use of Linnaeus or other classification methods which can be seen as insignificantly better when it comes to evolutionary manifestations of properties and/or structures. In other words all evolutionary models are all imperfect and so it is that the solution must indeed be imperfect too if it is to reflect the true nature of the Natural World i.e. testing is necessary before any firm conclusions can be reached. The use of the hook is a not very interesting thing, relatively. But it is also the ideal way to start with the designing of micro-sized (~100micron) objects because of the over-hangs of the hooks, which are of the minimal complexities to test the programmer and they can be assembled into machine-like components for manufacture. Their origins are a little too old for one to understand their development since the designs are based in evolutionary theory, which is utilised in order to identify which structures are viable and of suitable length and strength to be of use in the manufacture of computer components to attach to PCB’s (printed circuit boards).

THE THESIS PROPOSAL

This work derives from a thesis proposal: “The Functional Ecology and Mechanical Properties of Biological Hooks in Nature”. This is another way of requesting the classification of the set of all hooks according to their shape/structure and mechanical properties and here a simple method of assessing a structure is utilised and that is by naked eye, from the outside with no internal examination. This would correspond to the earliest form of Naturalism prsumably, classifying flora and fauna according to their appearance and function. Dissatisfaction with the current methods of shape acquisition and manufacture led to the research path which was followed.

It led to the theory that there is a way of being able to measure the proportional forces being used in the attachment of those mechanisms that could be measured and used to manufacture a hook that would indeed be of use, but not as expected. i.e. A hook shape need not be used only, if at all, for mechanical interlock. It is those hidden secrets that are sought, hidden from the human eye but not from the measuring instruments.

Current technology in 2002/3, where the latest paper on shape acquisition detailed the profile of a tiger’s claw [5] using 2-D digitising, was inadequate. Now through the work of Hirt et al [6], by their work on SEM (scanning electrodeposition electron microscopy) it is possible to move forward. Now a hook can be manufactured at a 1:1 scale to the fluorescent and translucent biological specimen that is to be reverse engineered and that means that designers are on the brink of being able to make things that are of use, in the micro-realm (of the order of 10-100 microns in size). It all began with the discovery that it was possible to image one of the hooked probabilistic fasteners under laser light, namely the cellulose hook of burdock (Arctium minus). Therefore the work continued with the chitinous growths of the bee and the grasshopper (Apis mellifera and Omocestus viridulus) tarsi [2]. This encounter with luck was able to make true the theory that the use of the single phase confocal microscope could be for the imaging of a specimen and then the transfer of data directly to a layered manufacture device that was suitable, namely the SEM work of Hirt et al [6]. The point of this imaging was to use it to describe each member of the class of probabilistic fasteners as a number, namely one for the hook, two for the attachment mechanism of the grasshopper O. viridulus with two hooks, and three for the double set of hooks, namely A. mellifera with a separating arolium which could make it all seem like they are intended to prove the theory right and not wrong. The chance of being on top of a specimen structure available without travelling is immense, as these were all available at the University of Bath which is set in the countryside of Western England. Particularly the burdock which was used as the basis of Velcro but it is concluded this is not the limit and it seemed better to use it than to use the others (see below), as it will be shown, for the production of a new hook, a multi-use flat structure of multiple hooks that could be used without being entirely known, as per its value and knowledge. i.e. if it is to be the one to be imitated then it needs to be studied more now so that it can be manufactured.

INSERT FIGURE 1 AND CAPTION

Referring to the Figure of the A. minus (burdock) “head” or seedpod, which along with the other four hook specimens studied by Gorb, namely the Agrimonia eupatoria, Circaea lutetiana, Galium aparine, and Geum urbanum” [7], all form probabilistic fasteners which is an important classification.

AIM

The aim is to develop a Universal micro-robotic frictional probablistic attachment mechanism with a performance that can be modelled graphically, using Biomimetic principles. This is called a Universal Foot after the fact that a human foot is a frictional probabilistic attachment mechanism and because its performance is to be modelled graphically for design, performance, material, quality and other parameters, its universal qualities. Cladistic methods are used for selection of a long-shafted, probabilistic, frictional, cellulose hook as a basis for the design.

METHOD

The above question is asked because the burdock hook is stronger and not weaker and therefore the best example to be reproduced and hence it is of the best form, whether of cellulose or of chitin, since it has a long shaft and an end that is available to the head of a layered manufacturing device. In the end it is a misnomer to think that it could be any more than a reproduction of the shaft that makes it fast and not slow to reproduce since it is of a cellulose hook, not chitin which is a very complicated biomaterial and therefore it is not easy to reproduce its properties. With cellulose however, it is a known material that has been much studied and therefore it is available to be reproduced via a green theory workplace in the future. Until then we shall make do with copper, not gold, since it is the cheaper of the two and therefore available to mass production and can be seen to be the best fit for the solution of making a reproduce-able hook that will sustain in making it to the end of the product lifecycle. See [6]. Figure 2 below shows the single-phase confocal microscope image sections that are utilised by SEM. Each .tiff file is used to construct a 3 dimensional image or the cubic voxels are directly utilised by the layered manufacturing device.

[INSERT FIGURE 2 AND CAPTION]

With respect to a Universal Foot it is impossible to sustain its probability of fastening since there is a possibility that it should not hold the correct angle on the surface/substrate. That will be overcome with a hinge that will allow the foot to align with the ground according to its angle and not the angle of application. It will be seen that there are a number of solutions to the problem of a Universal Foot and that means a testrig will have to be devised such that it can measure the forces with which a hook attaches to a substrate and that is the way through to the end of the series such that each member of the group of probabilistic fasteners can be measured, of different biological materials as imaged in [2]. In the meantime it is possible to make deductions such that a design can be arrived at that resembles a caterpillar yet makes use of the hook of the burdock and the range of movement that requires needful thinking so that it can be measured. Once this is done we have a product which can be commercialised. Part 2 [2] contains the results of the experimentation to image cellulose and chitin and this will prove useful in the future when a wide range of hooking and other mechanisms/devices are considered since it will be in the interest of those continuing the study to know the difference between the two and whether they can use the data to make hooks that are biological such as those to attach to the stomach wall or the vessels of the heart since they bear cilia which makes them difficult to render in a stainless steel as with a stent. But when it is available it may be possible to make them from a biological material which does not dissolve such as the Massachusetts Institute of Technology device which, when swallowed, removes a watch battery from the stomach wall to avoid a ulcer forming there or to patch a wound, steered by magnetic fields and which is still in the experimental phase. It is made from pig’s sinew which is insoluble but which does not lend itself to electro-deposition so an alternative biomaterial will need to be found. The electrodeposition of stainless steel has been investigated by Hasegawa et al [8] and it appears to allow for copper to be plated in stainless steel, enabling a biologically inert structure to be manufactured.

RESULTS

[INSERT FIGURE 3 AND CAPTION]

The result of this research is a hypothesis that has proved at least partly successful thus far. Please bear in mind that a design is being presented for a structure too small for human eye-sight to assess effectively. Within the constraints of Nachtigal’s classifications [9], three hooked classes have been imaged on a confocal microscope [2] and all that remains is to pass the data to the SEM of [6] to produce prototypes for testing. In a manner of regard, essentially multiple Class 1 hooks have been assembled in an array as a collective or field. They are shaped as per the cellulose form of the burdock hook which is simple and shows no stress modifications, with a tapered tip. Manufactured from copper, their attributes have yet to be discovered but it is hoped that it will yield an attachment device that will succeed in vertical assent via quadrupedal locomotion. It is designed to be multi-use, temporary and permanent, probabilistic and frictional as its mechanical properties. Its physical properties will of course differ not least for copper’s well-known capacitance to pass electric current and its magnetic properties.

[INSERT FIGURE 4 AND CAPTION]

DISCUSSION

For many years scientists have been studying the work done and methods of doing so in the animal world. The work being energy transfer and the methods, from walking to holding a stone as a hammer. It now has become possible to study the intimate details of the assembly of life and it is also becoming a useful aptitude to be able to make the correct decision with regards to design and this encompasses the system as well as the part itself which is being considered. So it becomes a necessary point to make that one can now physically reproduce to microns in accuracy and no longer is it necessary to stick to statistical methods of assessment and aspiration. Physical biology can now be measured at a micron level as can the performance of these structures, albeit in metal. These metal structures have yet to be tested but their material composition shall add to their value it is believed.

At a foundation has been a determined effort to move towards direct data transfer, from microscope image to layered manufacture, as it is called now. Because scaling effects exist, the mechanical properties of the vast majority of hooked attachment mechanisms can only be mimicked when manufactured at the same order of size.

[INSERT TABLE 1]

Table 1: Originating structures of long shafted hooks available in the literature. [1] and [7].

CONCLUSION

The door is creaking open, upon the region of science and manufacturing technology called Microdesign. As never before the opportunity arises for manufacturing expansion into the realm of micron-sized structural designs that could benefit man through their use of their size. In the light of new developments into Biomedical structures there is a need for stable materials at this scale to be used within biological systems. SEM has been proved accurate with both copper and gold so both are options to work with so far.

The hook, as a shape of low-complexity, proved an excellent example to demonstrate the limits of current technology and its new abilities due to the work of Hirt et al. In terms of 3-D date collection via laser scanning, resolution of an overhang is impossible in C++ programming terms unless one moves the head of the layered manufacturing device as per [6] in which case acute angles can be reproduced. Surface modelling via Canny Edge Detection methods does not provide for holes or overhangs in the first instance.

The set of all Biological hooks in Nature can be divided along lines of material, structure and function. When considering shape and form one must consider it surprising that all biomaterial seem able to form hook shapes and do. At the smallest scale, near atomic level and in the region where self-assembly occurs, there must be incentive to form these shapes which is a directed response to the environment. It could be that these early shapes, these hooks, were in fact invented by Life itself as a form of camouflage with dual purpose and thereby were able to be used to vary Life without threatening it. For the first, the very first curve or hook shapes on earth must have occurred in the rock material of the surface and other parts.

A crude mapping system is available to us at any time, much like a parts manufacturer would catalogue a system of related parts. But this is not the purpose of the research, which is into micro-design of which the hook-shape forms a complex challenge.

Figure 4 [10] shows a design space for fasteners, without microfasteners included except in the form of gecko-feet and a macro-sized form of velcro. There must be a place for these new microfasteners that are being suggested, microdesigned after Natural attachments that rise into the empty space of high relative strength and high-reusability on the chart.

REFERENCES

1. Saunders B E. Biomimetic study of natural attachment mechanisms-imaging cellulose and chitin part 2. J. Robot. Biomim. 2015;2:7. doi:10.1186/s40638-015-0032-9.

2. Saunders B E. A biomimetic study of natural attachment mechanisms – Arctium minus part 1. J. Robot. Biomim. 2015:2:4. DOI10.1186/s40638-015-0028-5

3. Saunders B E Microdesign using frictional, hooked, attachment mechanisms: a biomimetic study of natural attachment mechanisms – part 3. J. Robot. Biomim. 2016:3:4. DOI10.1186/s40638-016-0040-4

4. Mattheuk C and Reuss S The Claw of the Tiger: An Assessment of its Mechanical Shape Optimization, J. theor. Biol. (1991) 150, 323-328

5. Nicklaus, K. J. Plant, (1992) Biomechanics – An engineering approach to plant form and function (Chapter 10), Biomechanics and Plant Evolution, University of Chicago Press, pp. 474–530

6. Hirt L, Ihle S, Pan Z, Dorwling-Carter L, Reiser A, Wheeler JM, Spolenak R, Vörös J, Zambelli T. Template-free 3D microprinting of metals using a force-controlled nanopipette for layer-by-layer electrodeposition. Adv Mater. 2016;. DOI:10.1002/adma.201504967.

7. Gorb E, Gorb SN Contact separation force of the fruit burrs in four plant species adapted to dispersal by mechanical interlocking. Plant Physiol Biochem. 2002;40:373–81

8. Hasegawa M, Yoon S, b Guillonneau G, Zhan Y, Frantz C, Niederberger C, Weidenkaff A, Michlerad J, Philippead L The electrodeposition of FeCrNi stainless steel: microstructural changes induced by anode reactions Phys. Chem. Chem. Phys., 2014,16, 26375-26384 DOI: 10.1039/C4CP03744H

9. “Biological Mechanisms of Attachment, The Comparative Morphology and Bioengineering of Organs for Linkage, Suction and Adhesion”, W Nachtigall, 1974 translated by M A Biederman-Thorson, Springer-Verlag, ISBN 3-540-06550-4

10. “Systematic Technology Transfer from Biology to Engineering” J F V Vincent and D L Mann, Phil. Trans. R Soc. Lond. A(2002) 360, pp 159-173

COPYRIGHT BRUCE E SAUNDERS 2020 NOT TO REPRODUCED IN ANY FORM WITHOUT EXPRESS PERMISSION FROM THE AUTHOR OR PROFESSOR ANDREW PARKER, OXFORD UNIVERSITY

THE DESIGN OF A UNIVERSAL FOOT FOR ATTACHMENT OF A ROBOT TO WALLS AND CEILINGS

INTRODUCTION

Industry is by its very Nature not green, as we invest energy to create a form of order that is opposed to the natural thermodynamic qualities of the environment. So to look to Biomimetics for a green technological solution is a naive fallacy and inhibiting to the very science of biomimetics where there are rules and principles to be obeyed but they are not limited to the green solutions others seem to propose.

It is about the principles of chemistry and physics, not the policy of a politician. It is about the modelling of a system, not the shaping of a world, which must be in other people’s hands. Nature is about chaos, not process, self-assembly without apparent direction or control system, and does not serve the human race. If a biomimetic solution is found to nuclear waste disposal from power plants, would you call it “green”? Or would you call it chemistry? Or physics? Is a mutation green?

This is a fundamental that is misunderstood by most writers as they adopt populist theories in order to sell, not knowing the true value of it as they ignore avenues open to research in other fields that must prove that biomimetics is useful to mankind but not secular. It does not hold that Intelligent Design is about Nature. It is about perception.

A new definition of Biomimetics could be “the modelling of biological processes”. This is a coverall for all biomimetic processes witnessed in the laboratory as well as organic processes due to Nature.

The Biomimetic studies of flight and adhesion can be considered as two different systems for analysis, as a dynamic and a static system respectively. To reverse engineer studying flight we must take Nature into the laboratory and study it in a manner that may be transferred to the manufacturing shop floor. This means a methodology needs to be developed that reliably establishes the trends of flight and its parameters.

It is simple to understand that robotic flight will require robotic control and the use of actuators. Once we understand the pattern of movement, we can model this through Simulink(c) to produce an integrated circuit that will do what we want i.e. produce the motions of flight. All we need therefore is a high speed projection of a bee in flight, digitising its wing flutter to mark changes in angle of attack and yawl etc.

Now that Hirt et al [1] have shown it possible to produce structures of the order of size and shape of real instect tarsii in copper, it should be possible to begin the inspection of the surface interactions between small hooks and their substrates.

The underlying hypothesis behind the exploration of the detail of papers [2] and [3] accepts the viability of using cladistic methods to arrive at a scenario where a structure that has survived the “evolutionary sieve” is selected, to quote Nicklaus et al [5], over the use of Linnaeus or other classification methods which can be seen as insignificantly better when it comes to evolutionary manifestations of properties and/or structures. In other words all evolutionary models are all imperfect and so it is that the solution must indeed be imperfect too if it is to reflect the true nature of the Natural World i.e. testing is necessary before any firm conclusions can be reached. The use of the hook is a not very interesting thing, relatively. But it is also the ideal way to start with the designing of micro-sized (~100micron) objects because of the over-hangs of the hooks, which are of the minimal complexities to test the programmer and they can be assembled into machine-like components for manufacture. Their origins are a little too old for one to understand their development since the designs are based in evolutionary theory, which is utilised in order to identify which structures are viable and of suitable length and strength to be of use in the manufacture of computer components to attach to PCB’s (printed circuit boards).

A UNIVERSAL FOOT FOR ATTACHMENT TO ALL SURFACES FOR A ROBOT

With respect to a Universal Foot it is impossible to measure its probability of fastening since there is a possibility that it may not hold the correct angle on the surface/substrate. That will be overcome with a hinge that will allow the foot to align with the ground according to its angle and not the angle of application. It therefore can be used by the military to develop further and so it is about to be since it has application to the frontier of technology and the use is yet to be completely foreseen, such as soft robotics, micro-robotics, biosensors, computer hardware, orthodontics and optical sensors through the use of copper which is a very known substance with qualities that have been researched and ascertained through its use as a strain gauge and other common applications.

It will be seen that there are a number of solutions to the problem of a Universal Foot and that means a test-rig will have to be devised such that it can measure the forces with which a hook attaches to a substrate and that is the way through to the end of the series such that each member of the group of probabilistic fasteners can be measured, of different biological materials as imaged in [3]. In the meantime it is possible to make deductions such that a design can be arrived at that resembles a caterpillar yet makes use of the hook of the burdock and the range of movement that requires needful thinking so that it can be measured. Once this is done we have a product which can be commercialised. Part 2 [3] contains the results of the experimentation to image cellulose and chitin and this will prove useful in the future when we consider a wide range of hooking and other mechanisms/devices since it will be in the interest of those continuing the study to know the difference between the two and whether they can use the data to make hooks that are biological such as those to attach to the stomach wall or the vessels of the heart since they bear cilia which makes them difficult to render in a stainless steel as with a stent. But when it is available it may be possible to make them from a biological material which does not dissolve such as the MIT device which, when swallowed, removes a watch battery from the stomach wall to avoid a ulcer forming there or to patch a wound, steered by magnetic fields and which is still in the experimental phase. It is made from pig’s sinew which is insoluble but which does not lend itself to electro-deposition of course so an alternative will need to be found. The electrodeposition of stainless steel has been investigated by Hasegawa et al [6] and it shows that an improvement has been made to the processing of an otherwise inert steel that does not corrode or “anodize” and it can be electro-deposited on copper. This will make the stainless steel coated copper relatively biologically inert.

AIM

To produce a study plan for the solving of one of Nature’s greatest questions: How does a bee stick to a wall?

APPARATUS

Layered manufacturing device as described in [1]

Confocal microscope (single or two phase)

METHOD

1. Examine a specimen of insect chitin under the confocal microscope, output in .tiff files.

2. Transfer output .tiffs to the layered manufacturing device to produce a sample of a reverse engineered tarsus as described in Figure [] below.

3. Test the result for adhesion with a flat frictionless substrate and others.

RESULTS

1. 2. 3.

4. 5. 6.

7. 8. 9.

10. 11. 12.

13. 14. 15.

16. 17. 18.

19. 20. 21.

22. 23. 24.

25. 26. 27.

28. 29. 30.

Caption:

Figure 1: Images 1-30 are the sections of natural luminescence through a common bee tarsus using a single phase confocal microscope. (see [3])

DISCUSSION

For many years scientists have been studying the work done and methods of doing so in the animal world. The work being energy transfer and the methods, from walking to holding a stone as a hammer. It now has become possible to study the intimate details of the assembly of life and it is also becoming a useful aptitude to be able to make the correct decision with regards to design and this encompasses the system as well as the part itself which is being considered. So it becomes a necessary point to make that one can now physically reproduce to microns in accuracy and no longer is it necessary to stick to statistical methods of assessment and aspiration. Physical biology can now be measured at a micron level as can the performance of these structures, albeit in a metal. These metal structures have yet to be tested but their material composition shall add to the value of the design durability.

At a foundation has been a determined effort to move towards direct data transfer, from microscope image to layered manufacture, as it is called now. Because scaling effects exist, the non-Newtonian mechanical properties of the vast majority of hooked attachment mechanisms can only be mimicked and tested when manufactured at the same order of size.

CONCLUSION

The door is creaking open, upon the region of science and manufacturing technology called Microdesign. As never before the opportunity arises for manufacturing expansion into the realm of micron-sized structural designs that could benefit man through their use of their size. In the light of new developments into biomedical structures there is a need for stable materials at this scale to be used within biological systems.

The hook, as a shape of low-complexity, proved an excellent example to demonstrate the limits of current technology and its new abilities due to the work of Hirt et al [1]. In terms of 3-D data collection via laser scanning, resolution of an overhang is impossible in C++ programming terms unless one moves the head of the layered manufacturing device in which case complex shapes can be reproduced. Surface modelling via Canny Edge Detection methods does not provide for holes or overhangs in the first instance.

The set of all Biological hooks in Nature can be divided along lines of material, structure and function. When considering shape and form one must consider it surprising that all biomaterial seem able to form hook shapes and do. At the smallest scale, near atomic level and in the region where self-assembly occurs, there must be incentive to form these shapes which is a directed response to the environment. It could be that these early shapes, these hooks, were in fact invented by Life itself as a form of camouflage with dual purpose and thereby were able to be used to vary Life without threatening it. For the first, the very first curve or hook shapes on earth must have occurred in the rock material of the surface and other parts.

A crude mapping system is available to us at any time, much like a parts manufacturer would catalogue a system of related parts. But this is not the purpose of the research, which is into micro-design of which the hook-shape forms a complex challenge.

Caption:

Figure 5: This shows a design space for fasteners, without microfasteners included except in the form of gecko-feet and a macro-sized form of velcro. There must be a place for these new microfasteners that are being suggested, microdesigned after Natural attachments that rise into the empty space of high relative strength and high-reusability on the chart. A Universal Foot would have high adaptability and variable strength. [7]

This important work by Hirt et al has physical significance outside that of biomimetic applications. The output, in copper, has potential uses such as the brushes on micromachines.

REFERENCES

1. Hirt L, Ihle S, Pan Z, Dorwling-Carter L, Reiser A, Wheeler JM, Spolenak R, Vörös J, Zambelli T. Template-free 3D microprinting of metals using a force-controlled nanopipette for layer-by-layer electrodeposition. Adv Mater. 2016;. doi:10.1002/adma.201504967.

2. Saunders B. Biomimetic study of natural attachment mechanisms—Arctium minus part 1. J. Robot. Biomim. Special issue on Micro-/Nanorobotics. 2015;2:4.

3. Saunders B. Biomimetic study of natural attachment mechanisms—imaging cellulose and Chitin part 2. J. Robot. Biomim. 2015;2:7. doi:10.1186/s40638-015-0032-9.

4. Saunders B., Microdesign using frictional, hooked, attachment mechanisms: a biomimetic study of natural attachment mechanisms—Part 3

5. Nicklaus, K. J. Plant, (1992) Biomechanics – An engineering approach to plant form and function (Chapter 10), Biomechanics and Plant Evolution, University of Chicago Press, pp. 474–530

6. Hasegawa M, Yoon S, b Guillonneau G, Zhan Y, Frantz C, Niederberger C, Weidenkaff A, Michlerad J, Philippead L The electrodeposition of FeCrNi stainless steel: microstructural changes induced by anode reactions Phys. Chem. Chem. Phys., 2014,16, 26375-26384 DOI: 10.1039/C4CP03744H

7. “Systematic Technology Transfer from Biology to Engineering” J F V Vincent and D L Mann, Phil. Trans. R Soc. Lond. A(2002) 360, pp 159-173

ABSTRACT

Long has been the interest in the manner in which insects fly and land on walls and ceilings and windows of houses, since the beginning of recorded time. The start of the design must be with the introduction of micron accuracy in manufacture and design. Then it will be possible to study the forces acting upon a tarsus and model them mathematically to produce a Universal foot, an attachment mechanism that can bear the weight of a robot, or part of it. Here it is discussed in the context of knowledge transfer from the laboratory to the design. A copper element coated in stainless steel is proposed and described.

COPYRIGHT BRUCE E SAUNDERS 2020 NOT TO REPRODUCED IN ANY FORM WITHOUT EXPRESS PERMISSION FROM THE AUTHOR OR PROFESSOR ANDREW PARKER, OXFORD UNIVERSITY

Title: The micro-design of hooked biological attachment mechanisms and soft robotics – a Biomimetic approach.

Abstract:

Hooked attachment mechanisms are a subset of all Biological Attachment Mechanisms and a useful starting position for experiments on the imaging of all biological attachment mechanisms such that they can be adopted in the engineering domain. A hook has an overhang which makes the imaging and transfer to .stl format a challenge, a test that once passed, allows for the further imaging of attachment mechanisms of all shapes and of differing materials. Confocal microscopy seems to have solved the issue so that it is now possible to move from the attachment mechanism directly to the finished model without user interference [1]. Here, the work to-date is summarised, imaging cellulose and chitin hooks so that the process can move forward to other attachment devices of interest such as the mating parts of sexual organs in insects or other biological sub-structures that are not hooked. Progress is reported to have been made into the development of chitin nano-tubules so clearly there is hope that this work will yield a standard for mechanical attachment mechanisms of soft tissues or materials that can interact safely with human flesh with medical applications.

Keywords: hooks, probability, scaling effects, biomaterials.

INTRODUCTION

This is a review article of the three papers published in the Springer-Open journal, “The Journal of Robotics and Biomimetics” in a special issue on nano-/micro-robotics under the following titles:

1. A biomimetic study of natural attachment mechanisms— Arctium minus part 1 [2]

2. A biomimetic study of natural attachment mechanisms: imaging cellulose and chitin part 2 [3]

3. Micro-design using frictional, hooked, attachment mechanisms: a biomimetic study of natural attachment mechanisms—Part 3 [1]

The title of part 3 above displays the underlying motive behind the exploration of the detail of papers 1 and 2. It accepts the viability of using cladistic methods to arrive at a scenario where a structure that has survived the “evolutionary sieve” is selected, to quote Nicklaus et al [4], over the use of Linnaeus or other classification methods which can be seen as insignificantly better when it comes to evolutionary manifestations of properties and/or structures. [5] goes some way to describing this technology transfer.

The first view was that it was unsuitable to study with available technology. The decision was made to proceed with the use of a confocal microscope instead of light microscopy. Subsequently it has become possible only through the work of Hirt et al [6], by their work on a layered manufacturing device that can accept .tiff files as input and produce form. Now a hook can be manufactured at a 1:1 scale to the specimen that is to be reverse engineered and that means that designers are on the brink of being able to make things that are of use, in the micro-realm (of the order of 10-100 microns in size). It all began with the discovery that it was possible to image one of the hooked probabilistic fasteners under laser light, namely the cellulose hook of burdock (Arctium minus). Therefore the work continued with the chitinous growths of the bee and the grasshopper (Apis mellifera and Omocestus viridulus) tarsii [3]. This encounter with luck was able to make true the theory that the use of the microscope could be for the imaging of a specimen and then the transfer of data directly to a layered manufacture device that was suitable, namely the work of Hirt et al. The point of this imaging was to use it to describe the group of probabilistic fasteners as a number, namely one for the hook, two for the attachment mechanism of the grasshopper O. viridulus with two hooks, and three for the double set of hooks, namely A. mellifera with a separating arolium, irrespective of component material.

The chance of being on top of a specimen structure available without travelling was immense, as these were all available at the University of Bath which is set in the countryside of Western England. Particularly the burdock which is used (apparently) as the basis of Velcro but it is concluded this is without fundament and it seemed better to use it than to use the others (see below), as it will be shown, for the production of a new hook, a multi-use flat structure of multiple hooks that could be used without being entirely known, as per its value and knowledge. i.e. if it is to be the one to be imitated then it needs to be studied more now so that it can be manufactured.

Caption:

Figure 1: An Arctium minus (commonly known as burdock) fruit showing milli-metric scale. [1]

In Part 1 of the investigation [3], the cellulose hooks of burdock revealed a scaling effect [5] under loading. This is because the hook un-rolls as it is loaded until the radius of curvature is increased in size at fracture, in a similar manner in which a length of iron chain cannot be horizontally loaded until it is pulled straight without failing. The material is simply not as stiff as it would appear in the sketch of the structure for analytical purposes with its Newtonian assumptions and its properties vary under conditions, such as its state of dessication.

The reasons for this have been considered but not concluded as of yet, requiring further inspection of the material properties. All the natural cellulose hooks studied in the literature, Agrimonia eupatoria, Circaea lutetiana, Galium aparine, and Geum urbanum as well as Arctium minus, have been described in terms of their originating structures [2][8].

Caption:

Table 1: Grouping the cellulose, probabilistic, frictional and long-shafted hooks according to originating structure. [2] and [8][9].

The cellular complexity obviously plays a part and from [2] the micro-fibril strengthening of the structure must play a part too, but this does not satisfy the Newtonian equations of static analysis used for hooks of a larger size. This is an exciting find since it suggests that there may be differing laws governing the behaviour of structures at this level other than standard analysis, rather in the way that the behaviour of fluids differ under different flow conditions [10] governed by the energy equation. Therefore the sense is that it is best to mimic the morphology exactly in order to yield optimal performance and maximum attachment strength when fastened, through fiction and mechanical attachment, bearing in mind that a hook must be paired with a substrate.

COPYRIGHT BRUCE E SAUNDERS 2020

INTRODUCTION

Industry is by its very Nature not green, as we invest energy to create a form of order that is opposed to the natural thermodynamic qualities of the environment. So to look to Biomimetics for a green technological solution is a naive fallacy and inhibiting to the very science of biomimetics where there are rules and principles to be obeyed but they are not limited to the green solutions others seem to propose.

It is about the principles of chemistry and physics, not the policy of a politician. It is about the modelling of a system, not the shaping of a world, which must be in other people’s hands. Nature is about chaos, not process, self-assembly without apparent direction or control system, and does not serve the human race. If a biomimetic solution is found to nuclear waste disposal from power plants, would you call it “green”? Or would you call it chemistry? Or physics? Is a mutation green?

This is a fundamental that is misunderstood by most writers as they adopt populist theories in order to sell, not knowing the true value of it as they ignore avenues open to research in other fields that must prove that biomimetics is useful to mankind but not secular. It does not hold that Intelligent Design is about Nature. It is about perception.

A new definition of Biomimetics could be “the modelling of biological processes”. This is a coverall for all biomimetic processes witnessed in the laboratory as well as organic processes due to Nature.

The Biomimetic studies of flight and adhesion can be considered as two different systems for analysis, as a dynamic and a static system respectively. To reverse engineer flight we must take Nature into the laboratory and study it in a manner that may be transferred to the manufacturing shop floor. This means a methodology needs to be developed that reliably establishes the trends of flight and its parameters.

It is simple to understand that robotic flight will require robotic control and the use of actuators. Once we understand the pattern of movement, we can model this through Simulink(c) to produce an integrated circuit that will do what we want i.e. produce the motions of flight. All we need therefore is a high speed projection of a bee in flight, digitzing its wing flutter to mark changes in angle of attack and yawl etc.

Now that Hirt et al have shown it possible to produce structures of the order of size and shape of real instect tarsii in copper, it should be possible to begin the inspection of the surface interactions between small hooks and their substrates.

The underlying hypothesis behind the exploration of the detail of papers [2] and [3] accepts the viability of using cladistic methods to arrive at a scenario where a structure that has survived the “evolutionary sieve” is selected, to quote Nicklaus et al [4], over the use of Linnaeus or other classification methods which can be seen as insignificantly better when it comes to evolutionary manifestations of properties and/or structures. In other words all evolutionary models are all imperfect and so it is that the solution must indeed be imperfect too if it is to reflect the true nature of the Natural World i.e. testing is necessary before any firm conclusions can be reached. The use of the hook is a not very interesting thing, relatively. But it is also the ideal way to start with the designing of micro-sized (~100micron) objects because of the over-hangs of the hooks, which are of the minimal complexities to test the programmer and they can be assembled into machine-like components for manufacture. Their origins are a little too old for one to understand their development since the designs are based in evolutionary theory, which is utilised in order to identify which structures are viable and of suitable length and strength to be of use in the manufacture of computer components to attach to PCB’s (printed circuit boards).

With respect to a Universal Foot it is impossible to measure its probability of fastening since there is a possibility that it may not hold the correct angle on the surface/substrate. That will be overcome with a hinge that will allow the foot to align with the ground according to its angle and not the angle of application. It therefore can be used by the military to develop further and so it is about to be since it has application to the frontier of technology and the use is yet to be completely foreseen, such as soft robotics, micro-robotics, biosensors, computer hardware, orthodontics and optical sensors through the use of copper which is a very known substance with qualities that have been researched and ascertained through its use as a strain gauge and other common applications.

It will be seen that there are a number of solutions to the problem of a Universal Foot and that means a testrig will have to be devised such that it can measure the forces with which a hook attaches to a substrate and that is the way through to the end of the series such that each member of the group of probabilistic fasteners can be measured, of different biological materials as imaged in [2]. In the meantime it is possible to make deductions such that a design can be arrived at that resembles a caterpillar yet makes use of the hook of the burdock and the range of movement that requires needful thinking so that it can be measured. Once this is done we have a product which can be commercialised. Part 2 [2] contains the results of the experimentation to image cellulose and chitin and this will prove useful in the future when we consider a wide range of hooking and other mechanisms/devices since it will be in the interest of those continuing the study to know the difference between the two and whether they can use the data to make hooks that are biological such as those to attach to the stomach wall or the vessels of the heart since they bear cilia which makes them difficult to render in a stainless steel as with a stent. But when it is available it may be possible to make them from a biological material which does not dissolve such as the MIT device which, when swallowed, removes a watch battery from the stomach wall to avoid a ulcer forming there or to patch a wound, steered by magnetic fields and which is still in the experimental phase. It is made from pig’s sinew which is insoluble but which does not lend itself to electro-deposition of course so an alternative will need to be found. The electrodeposition of stainless steel has been investigated by Hasegawa et al [11] and it shows that an improvement has been made to the processing of an otherwise inert steel that does not corrode or “anodize” and it can be electro-deposited on copper. This will make the stainless steel coated copper relatively biologically inert.