Survey of biomechanical aspects of arthropod terrestrialisation – Substrate bound legged locomotion

Weihmann, Tom

doi:10.1016/j.asd.2020.100983

Cited by 12 publications

(19 citation statements)

References 229 publications

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“…Ancestral legged locomotor systems, just after a certain clade’s colonisation of land, were rather slow and did not exploit leg elasticities ( 21, 43 ). With such conditions, ipsilateral phase relations deviating from 0.5, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…Unfortunately, their energy content cannot be reconverted into forward movements ( 66 ). However, frequencies higher than twice the stride frequency are usually effectively dissipated due to the damping properties of the leg muscles and other internal structures ( 3, 21, 54, 67, 68 ), which is why these high frequencies are practically unobservable in animals. Nevertheless, in underdamped machines it can become a problem and should be taken into account.…”

Section: Discussionmentioning

confidence: 99%

“…rear legs alternated strictly, which, in quadrupedal animals, is a characteristic of symmetrical gaits ( 4 ). However, contralateral phase relations of about 0.5 are also often found in arthropods ( 21 ). In order to generate different leg coordination patterns, the θ of all ipsilateral legs were uniformly shifted from 0 to 1, which resulted in changing contralateral phase shifts in all leg pairs anterior to the rear legs.…”

Section: Methodsmentioning

confidence: 99%

“…The evolution of arthropods also seems to be characterised by repeated and independent reductions in the number of propulsive legs. Particularly in small terrestrial forms, these reductions have probably extensive advantages regarding locomotion energetics and control effort, and therefore may have influenced major morphological changes in the course of these animals’ transitions from marine to terrestrial habitats ( 21, 22 ).…”

Section: Introductionmentioning

confidence: 99%

“…This is true also in animals with sprawled legs such as reptiles or arthropods like insects and arachnids ( 8, 27, 31, 32 ). Accordingly and in absolute terms, overall vertical force amplitudes are particularly affected by phase shift induced ground force interferences, which makes them most decisive and characteristic for changes in COM dynamics and therefore gaits ( 1, 21 ).…”

Section: Introductionmentioning

confidence: 99%

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The smooth transition from many-legged to bipedal locomotion - Gradual ground force reduction and its impact on total ground reaction forces, body dynamics and gait transitions

Weihmann

2021

Preprint

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Most terrestrial animals move with a specific number of propulsive legs, which differs between clades. The reasons for these differences are often unknown and rarely queried, despite the underlying mechanisms being indispensable for understanding the evolution of multilegged locomotor systems in the animal kingdom and the development of swiftly moving robots. Moreover, when speeding up, a range of species change their number of propulsive legs. The reasons for this behaviour have proven equally elusive. In animals and robots, the number of propulsive legs also has a decisive impact on the movement dynamics of the centre of mass. Here, I use the leg force interference model to elucidate these issues by introducing gradually declining ground reaction forces in locomotor apparatuses with varying numbers of leg pairs in a first numeric approach dealing with these measures' impact on locomotion dynamics. The effects caused by the examined changes in ground reaction forces and timing thereof follow a continuum. However, the transition from quadrupedal to a bipedal locomotor system deviates from those between multilegged systems with different numbers of leg pairs. Only in quadrupeds do reduced ground reaction forces beneath one leg pair result in increased reliability of vertical body oscillations and therefore increased energy efficiency and dynamic stability of locomotion.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The smooth transition from many-legged to bipedal locomotion - Gradual ground force reduction and its impact on total ground reaction forces, body dynamics and gait transitions

Weihmann

2021

Preprint

Self Cite

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Correlation between ranges of leg walking angles and passive rest angles among leg types in stick insects

Guschlbauer¹,

Hooper²,

Mantziaris³

et al. 2022

Current Biology

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Shaping the energy curves of a servomotor-based hexapod robot

Brodoline,

Sauvageot,

Viollet

et al. 2024

Sci Rep

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The advantageous versatility of hexapod robots is often accompanied by high power consumption, while animals have evolved an energy efficient locomotion. However, there are a lack of methods able to compare and apply animals’ energetic optimizations to robots. In this study, we applied our method to a full servomotor-based hexapod robot to evaluate its energetic performance. Using an existing framework based on the laws of thermodynamics, we estimated four metrics using a dedicated test bench and a simulated robotic leg. We analyzed the characteristics of a single leg to shape the energetic profile of the full robot to a given task. Energy saving is improved by 10% through continuous duty factor adjustment with a 192% increase in power maximization. Moreover, adjusting the robot’s velocity by the step length and associating this with gait switching, reduces the power loss by a further 10% at low-speed locomotion. However, unlike in animals, only one unique optimal operating point has been revealed, which is a disadvantage caused by the low energetic efficiency of servomotor-based hexapods. Thus, these legged robots are severely limited in their capacity to optimally adjust their locomotion to various tasks—a counter-intuitive conclusion for a supposedly versatile robot.

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Survey of biomechanical aspects of arthropod terrestrialisation – Substrate bound legged locomotion

Cited by 12 publications

References 229 publications

The smooth transition from many-legged to bipedal locomotion - Gradual ground force reduction and its impact on total ground reaction forces, body dynamics and gait transitions

The smooth transition from many-legged to bipedal locomotion - Gradual ground force reduction and its impact on total ground reaction forces, body dynamics and gait transitions

Correlation between ranges of leg walking angles and passive rest angles among leg types in stick insects

Shaping the energy curves of a servomotor-based hexapod robot

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