scholarly journals Using a biologically mimicking climbing robot to explore the performance landscape of climbing in lizards

2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Johanna T. Schultz ◽  
Hendrik K. Beck ◽  
Tina Haagensen ◽  
Tasmin Proost ◽  
Christofer J. Clemente
Keyword(s):  
Functional Constraints ◽  
Climbing Robot ◽  
Cost Of Transport ◽  
Performance Tasks ◽  
Natural Systems ◽  
High Speeds ◽  
Extant Species ◽  
Climbing Ability ◽  
The Cost ◽  
Relative Weighting

Locomotion is a key aspect associated with ecologically relevant tasks for many organisms, therefore, survival often depends on their ability to perform well at these tasks. Despite this significance, we have little idea how different performance tasks are weighted when increased performance in one task comes at the cost of decreased performance in another. Additionally, the ability for natural systems to become optimized to perform a specific task can be limited by structural, historic or functional constraints. Climbing lizards provide a good example of these constraints as climbing ability likely requires the optimization of tasks which may conflict with one another such as increasing speed, avoiding falls and reducing the cost of transport (COT). Understanding how modifications to the lizard bauplan can influence these tasks may allow us to understand the relative weighting of different performance objectives among species. Here, we reconstruct multiple performance landscapes of climbing locomotion using a 10 d.f. robot based upon the lizard bauplan, including an actuated spine, shoulders and feet, the latter which interlock with the surface via claws. This design allows us to independently vary speed, foot angles and range of motion (ROM), while simultaneously collecting data on climbed distance, stability and efficiency. We first demonstrate a trade-off between speed and stability, with high speeds resulting in decreased stability and low speeds an increased COT. By varying foot orientation of fore- and hindfeet independently, we found geckos converge on a narrow optimum of foot angles (fore 20°, hind 100°) for both speed and stability, but avoid a secondary wider optimum (fore −20°, hind −50°) highlighting a possible constraint. Modifying the spine and limb ROM revealed a gradient in performance. Evolutionary modifications in movement among extant species over time appear to follow this gradient towards areas which promote speed and efficiency.

scholarly journals Using a biologically mimicking climbing robot to explore the performance landscape of climbing in lizards

2021 ◽  
Author(s):  
Johanna T. Schultz ◽  
Hendrik K. Beck ◽  
Tina Haagensen ◽  
Tasmin Proost ◽  
Christofer J. Clemente
Keyword(s):  
Climbing Robot ◽  
Range Of Movement ◽  
Or Efficiency ◽  
Cost Of Transport ◽  
Natural Systems ◽  
Life And Death ◽  
Rates Of Evolution ◽  
Extant Species ◽  
Relevant Task ◽  
Speed Stability

AbstractThe life and death of an organism often depends on its ability to perform well at some ecologically relevant task. Yet despite this significance we have little idea how well species are optimised for competing locomotor tasks. Most scientists generally accept that the ability for natural systems to become optimised for a specific task is limited by structural, historic or functional constraints. Climbing lizards provide a good example of constraint where climbing ability requires the optimization of conflicting tasks such as speed, stability, or efficiency. Here we reconstruct multiple performance landscapes of climbing locomotion using a 10-DOF robot based upon the lizard bauplan, including an actuated spine, shoulders, and feet, the latter which interlock with the surface via claws. This design allows us to independently vary speed, foot angles, and range of motion, while simultaneously collecting data on climbed distance, stability and efficiency. We first demonstrate a trade-off between speed and stability with high speeds resulting in decreased stability and low speeds an increased cost of transport. By varying foot orientation of fore and hindfeet independently, we found geckos converge on a narrow optimum for both speed and stability, but avoid a secondary wider optimum highlighting a possible constraint. Modifying the spine and limb range of movement revealed a gradient in performance. Evolutionary modifications in movement among extant species appear to follow this gradient towards areas which promote speed and efficiency. This approach can give us a better understanding about locomotor optimization, and provide inspiration for industrial and search-and-rescue robots.Significance StatementClimbing requires the optimization of conflicting tasks such as speed, stability, or efficiency, but understanding the relative importance of these competing performance traits is difficult.We used a highly modular bio-inspired climbing robot to reconstruct performance landscapes for climbing lizards. We then compared the performance of extant species onto these and show strong congruence with lizard phenotypes and robotic optima.Using this method we can show why certain phenotypes are not present among extant species, illustrating why these would be potentially mal-adaptive.These principles may be useful to compare with relative rates of evolution along differing evolutionary histories. It also highlights the importance of biological inspiration towards the optimization of industrial climbing robots, which like lizards, must negotiate complex environments.

scholarly journals Relations between morphology, buoyancy and energetics of requiem sharks

2016 ◽  
Vol 3 (10) ◽  
pp. 160406 ◽  
Author(s):  
Gil Iosilevskii ◽  
Yannis P. Papastamatiou
Keyword(s):  
Body Temperature ◽  
Negative Selection ◽  
Swimming Performance ◽  
Ontogenetic Changes ◽  
Cost Of Transport ◽  
Pectoral Fins ◽  
Confined Spaces ◽  
Reef Sharks ◽  
The Cost ◽  
Derivatives Of

Sharks have a distinctive shape that remained practically unchanged through hundreds of millions of years of evolution. Nonetheless, there are variations of this shape that vary between and within species. We attempt to explain these variations by examining the partial derivatives of the cost of transport of a generic shark with respect to buoyancy, span and chord of its pectoral fins, length, girth and body temperature. Our analysis predicts an intricate relation between these parameters, suggesting that ectothermic species residing in cooler temperatures must either have longer pectoral fins and/or be more buoyant in order to maintain swimming performance. It also suggests that, in general, the buoyancy must increase with size, and therefore, there must be ontogenetic changes within a species, with individuals getting more buoyant as they grow. Pelagic species seem to have near optimally sized fins (which minimize the cost of transport), but the majority of reef sharks could have reduced the cost of transport by increasing the size of their fins. The fact that they do not implies negative selection, probably owing to decreased manoeuvrability in confined spaces (e.g. foraging on a reef).

New Evolutionary Algorithm Based on 2-Opt Local Search to Solve the Vehicle Routing Problem with Private Fleet and Common Carrier

2012 ◽  
pp. 125-148
Author(s):  
Jalel Euchi ◽  
Habib Chabchoub ◽  
Adnan Yassine
Keyword(s):  
Local Search ◽  
Evolutionary Algorithm ◽  
Vehicle Routing ◽  
Cost Savings ◽  
Alternative Mode ◽  
Cost Of Transport ◽  
Routing Problem ◽  
The Cost ◽  
Specific Assignment ◽  
Selection Of

Mismanagement of routing and deliveries between sites of the same company or toward external sites leads to consequences in the cost of transport. When shipping alternatives exist, the selection of the appropriate shipping alternative (mode) for each shipment may result in significant cost savings. In this paper, the authors examine a class of vehicle routing in which a fixed internal fleet is available at the warehouse in the presence of an external transporter. The authors describe hybrid Iterated Density Estimation Evolutionary Algorithm with 2-opt local search to determine the specific assignment of each tour to a private vehicle (internal fleet) or an outside carrier (external fleet). Experimental results show that this method is effective, allowing the discovery of new best solutions for well-known benchmarks.

scholarly journals Soaring Flight in the Eleonora's Falcon (Falco eleonorae)

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 835-840 ◽  
Author(s):  
Mikael Rosén ◽  
Anders Hedenström
Keyword(s):  
Flight Behavior ◽  
Small Island ◽  
Cost Of Transport ◽  
Open Sea ◽  
Gliding Flight ◽  
Eleonora’S Falcon ◽  
Soaring Flight ◽  
Falco Eleonorae ◽  
Vertical Winds ◽  
The Cost

Abstract Eleonora's Falcon (Falco eleonorae) breeds in the Mediterranean region and is highly adapted for catching small birds on passage migration between Eurasia and their African winter quarters, which they feed their young. We studied gliding flight behavior of Eleonora's Falcon at a breeding colony located on a small island southwest of Sardinia, Italy. Gliding and soaring flight performance was measured using an optical range finder and evaluated against flight mechanical theory. The male falcon does the majority of hunting and usually sets off from the colony to hunting areas located at high altitude over the open sea to catch prey. To lower the cost of transport and maximize the energy gain from hunting, we show that the birds use vertical winds for soaring when available. The occurrence of rising air changes with wind direction. At north-northwesterly winds (on-shore), slope lift is available outside the nesting cliffs, and at south-southeasterly winds thermals that form over the island drift out over the sea. Our observations demonstrated the flexibility of flight behavior in relation to the wind situation, and birds thereby make full use of available soaring conditions.

Nature

2021 ◽  
pp. 188-222
Keyword(s):  
Functional Constraints ◽  
Natural Systems ◽  
Energy Footprint ◽  
Efficient Performance ◽  
Historical Origins ◽  
Simple Interaction

This chapter discusses the historical origins of the concept of borrowing from nature and coining the science of bio-mimetics. The material also surveys examples of tribological systems in nature. Generation of design in natural systems (geometry, pattern, form, and texture) is shown to be holistic in essence. It synchronizes simple interaction of design constituents and efficient performance. Such an approach yields deterministic design outputs that while conceptually simple are of minimized energy footprint. Natural engineering, it is shown, seeks trans-disciplinary technically viable alternatives to our technological practices. These alternatives, given functional constraints, require minimum effort to construct and economize effort while functioning.

scholarly journals Brain size is correlated with endangerment status in mammals

2016 ◽  
Vol 283 (1825) ◽  
pp. 20152772 ◽  
Author(s):  
Eric S. Abelson
Keyword(s):  
Brain Size ◽  
Extinction Risk ◽  
Small Body ◽  
Cost Benefit ◽  
Metabolic Cost ◽  
Trade Offs ◽  
Extant Species ◽  
Body Sizes ◽  
The Cost ◽  
The Relationship

Increases in relative encephalization (RE), brain size after controlling for body size, comes at a great metabolic cost and is correlated with a host of cognitive traits, from the ability to count objects to higher rates of innovation. Despite many studies examining the implications and trade-offs accompanying increased RE, the relationship between mammalian extinction risk and RE is unknown. I examine whether mammals with larger levels of RE are more or less likely to be at risk of endangerment than less-encephalized species. I find that extant species with large levels of encephalization are at greater risk of endangerment, with this effect being strongest in species with small body sizes. These results suggest that RE could be a valuable asset in estimating extinction vulnerability. Additionally, these findings suggest that the cost–benefit trade-off of RE is different in large-bodied species when compared with small-bodied species.

scholarly journals The rising cost of warming waters: effects of temperature on the cost of swimming in fishes

2011 ◽  
Vol 8 (2) ◽  
pp. 266-269 ◽  
Author(s):  
Andrew M. Hein ◽  
Katrina J. Keirsted
Keyword(s):  
Water Temperature ◽  
Fish Species ◽  
Global Climate ◽  
Swimming Performance ◽  
Metabolic Cost ◽  
Quantitative Model ◽  
The Body ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
The Cost

Understanding the effects of water temperature on the swimming performance of fishes is central in understanding how fish species will respond to global climate change. Metabolic cost of transport (COT)—a measure of the energy required to swim a given distance—is a key performance parameter linked to many aspects of fish life history. We develop a quantitative model to predict the effect of water temperature on COT. The model facilitates comparisons among species that differ in body size by incorporating the body mass-dependence of COT. Data from 22 fish species support the temperature and mass dependencies of COT predicted by our model, and demonstrate that modest differences in water temperature can result in substantial differences in the energetic cost of swimming.

scholarly journals How (much) do flowers vary? Unbalanced disparity among flower functional modules and a mosaic pattern of morphospace occupation in the order Ericales

2017 ◽  
Vol 284 (1852) ◽  
pp. 20170066 ◽  
Author(s):  
Marion Chartier ◽  
Stefan Löfstrand ◽  
Maria von Balthazar ◽  
Sylvain Gerber ◽  
Florian Jabbour ◽  
...  
Keyword(s):  
Morphological Diversity ◽  
Floral Traits ◽  
Functional Modules ◽  
Functional Constraints ◽  
Mosaic Pattern ◽  
Quantitative Distribution ◽  
Relative Contribution ◽  
Extant Species ◽  
Functional Patterns ◽  
Quantitative Analyses

The staggering diversity of angiosperms and their flowers has fascinated scientists for centuries. However, the quantitative distribution of floral morphological diversity (disparity) among lineages and the relative contribution of functional modules (perianth, androecium and gynoecium) to total floral disparity have rarely been addressed. Focusing on a major angiosperm order (Ericales), we compiled a dataset of 37 floral traits scored for 381 extant species and nine fossils. We conducted morphospace analyses to explore phylogenetic, temporal and functional patterns of disparity. We found that the floral morphospace is organized as a continuous cloud in which most clades occupy distinct regions in a mosaic pattern, that disparity increases with clade size rather than age, and that fossils fall in a narrow portion of the space. Surprisingly, our study also revealed that among functional modules, it is the androecium that contributes most to total floral disparity in Ericales. We discuss our findings in the light of clade history, selective regimes as well as developmental and functional constraints acting on the evolution of the flower and thereby demonstrate that quantitative analyses such as the ones used here are a powerful tool to gain novel insights into the evolution and diversity of flowers.

A Gecko-Inspired Robot for Wind Power Tower Inspection

2013 ◽  
Vol 461 ◽  
pp. 831-837
Author(s):  
Xue Shan Gao ◽  
Jie Shao ◽  
Fu Quan Dai ◽  
Cheng Guo Zong ◽  
Wen Zeng Guo
Keyword(s):  
Wind Power ◽  
Design Method ◽  
Degree Of Freedom ◽  
Small Radius ◽  
Wall Surface ◽  
Climbing Robot ◽  
Soft Body ◽  
Climbing Ability

In order to accomplish the task of wind power tower inspection, a heavy-loaded climbing robot inspired by geckos is presented in this paper. The robot not only imitates body’s functions of geckos but also shows a design method. Wind power tower is a conical wall surface and its smallest radius is less than 2m. There will be a great gap when a robot climbing on such wall with small radius. The extraordinary climbing ability of geckos is considered as a remarkable design of nature that is attributed to its soft body, its multi-degree-of-freedom legs, and its strong-adsorbed toes. Focus on the feature of working on such wall surface, gecko’s body, toes and legs are simplified as free joints, magnetic units and redundant tracks respectively, based on the functions of gecko’s limbs and body. The adaptability of the robot is tested by the experiments in laboratory. With the gecko-inspired structure, the robot can climb on the wall surface with minimum 2m in diameter in any direction.

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