Pedestrian Locomotion Research Articles

Reactive pedestrian path following from examples

Architectural and urban planning applications require animations of people to present an accurate and compelling view of a new environment. Ideally, these animations would be easy for a non-programmer to construct, just as buildings and streets can be modeled by an architect or artist using commercial modeling software. In this paper, we explore an approach for generating reactive path following based on the user's examples of the desired behavior. The examples are used to build a model of the desired reactive behavior. The model is combined with reactive control methods to produce natural 2D pedestrian trajectories. The system then automatically generates 3D pedestrian locomotion using a motion-graph approach. We discuss the accuracy of the learned model of pedestrian motion and show that simple direction primitives can be recorded and used to build natural, reactive, path-following behaviors.

ENERGY COST OF LOCOMOTION: VALIDATION OF LABORATORY DATA BY IN SITU RESPIROMETRY

The energy cost of activities central to overall fitness in most animals, such as pedestrian locomotion, is traditionally measured in the laboratory and then extrapolated to field conditions for modeling or hypothesis-testing purposes. However, no accurate, direct, in situ validation of these extrapolations has been made on undisturbed animals. We present the first such validation here, on harvester ants (Messor pergandei). After measuring their energy parameters in the laboratory using a running tube, we measured the metabolic rate (MR) of a natural, undisturbed ant trail foraging through a respirometer chamber in the field. From temperature, ant numbers, ant masses, and foraging speeds (obtained through video analysis), we predicted trail MRs from separately obtained laboratory data and compared them to measured field trail MRs. No significant difference was found between actual field values and values predicted from equations produced from data acquired in the laboratory. Our results therefore serve to validate two unusual findings in ants, which would otherwise be troubling to extrapolate to field conditions: that their extrapolated MR at zero running speed does not differ from standard (resting) metabolic rate, and that their costs of transport are far lower than predicted on the basis of current allometric equations.

Underwater punting by an intertidal crab: a novel gait revealed by the kinematics of pedestrian locomotion in air versus water

As an animal moves from air to water, its effective weight is substantially reduced by buoyancy while the fluid-dynamic forces (e. g. lift and drag) are increased 800-fold. The changes in the magnitude of these forces are likely to have substantial consequences for locomotion as well as for resistance to being overturned. We began our investigation of aquatic pedestrian locomotion by quantifying the kinematics of crabs at slow speeds where buoyant forces are more important relative to fluid-dynamic forces. At these slow speeds, we used reduced-gravity models of terrestrial locomotion to predict trends in the kinematics of aquatic pedestrian locomotion. Using these models, we expected animals in water to use running gaits even at slow speeds. We hypothesized that aquatic pedestrians would (1) use lower duty factors and longer periods with no ground contact, (2) demonstrate more variable kinematics and (3) adopt wider stances for increased horizontal stability against fluid-dynamic forces than animals moving at the same speed on land. We tested these predictions by measuring the three-dimensional kinematics of intertidal rock crabs (Grapsus tenuicrustatus) locomoting through water and air at the same velocity (9 cm s-1) over a flat substratum. As predicted from reduced-gravity models of running, crabs moving under water showed decreased leg contact times and duty factors relative to locomotion on land. In water, the legs cycled intermittently, fewer legs were in contact with the substratum and leg kinematics were much more variable than on land. The width of the crab's stance was 19 % greater in water than in air, thereby increasing stability against overturning by hydrodynamic forces. Rather than an alternating tetrapod or metachronal wave gait, crabs in water used a novel gait we termed 'underwater punting', characterized by alternating phases of generating thrust against the substratum and gliding through the water.

Discontinuous ventilation and energetics of locomotion in the desert‐dwelling female mutillid wasp, Dasymutilla gloriosa

Abstract. Data on the discontinuous ventilation cycle and cost of pedestrian locomotion in female Dasymutilla gloriosa (Sauss.), a desert‐dwelling mutillid, are described and compared with equivalent data from other Hymenoptera. The discontinuous ventilation cycle was intermediate between that found in xeric and mesic hymenopterans, with the open phase being about 20% of the cycle. No noticeable flutter phase was observed. Thus D. gloriosa does not attempt to reduce respiratory water loss to the same extent as found in other desert dwelling Hymenoptera. The minimum cost of transport was significantly higher than that obtained for several ant species, indicating that ants are probably more efficient runners than any other Hymenoptera.

Issues for Aquatic Pedestrian Locomotion

Aquatic pedestrian locomotion represents an important mode of locomotion for many aquatic and amphibious animals, both extant and extinct. Unlike terrestrial locomotion where weight is the defining force, in aquatic locomotion buoyancy and hydrodynamic forces may be as important as weight. Aquatic pedestrian locomotion differs fundamentally from swimming because pedestrians must maintain contact with the substratum in order to locomote. Ambient water motion may constrain or prevent locomotion of aquatic pedestrians by requiring that they actively grip the substratum. A comprehensive biomechanical analysis of aquatic pedestrian locomotion will require an integration of hydrodynamics with terrestrial locomotor dynamics.

Energetics of Pedestrian Locomotion in Adult Male Blowflies, Protophormia terraenovae (Diptera: Calliphoridae)

We describe the metabolic cost of voluntary pedestrian locomotion in adult male blowflies, Protophormia terraenovae (Diptera: Calliphoridae) from measurements made in a running tube. The minimum cost of transport (MCOT) based on interindividual comparisons for male blowflies is 254 J kg⁻¹ m⁻¹ (SE = 41). This value was similar to the MCOT based on intraindividual comparisons (208 J kg⁻¹ m⁻¹, SE = 72). These estimates are very near the predicted MCOT for limbed arthropods of the same size, despite the fact that, unlike insects that rely exclusively on pedestrian locomotion, blowflies must carry a substantial mass of flight muscle while walking. The cost of transport for walking adult flies is almost an order of magnitude lower than the cost of crawling by larval flies. We also used ANCOVA to estimate the MCOT for individual flies tested at three temperatures: 28°, 32°, and 37° C. There was no detectable temperature-by-individual interaction or temperature effect on the MCOT, and the MCOT estimated by this procedure (319 J kg⁻¹ m⁻¹, SE = 83) was statistically indistinguishable from the estimates based on intra- and interindividual comparisons at a single temperature.

Similarity in multilegged locomotion: Bouncing like a monopode

Despite impressive variation in leg number, length, position and type of skeleton, similarities of legged, pedestrian locomotion exist in energetics, gait, stride frequency and ground-reaction force. Analysis of data available in the literature showed that a bouncing, spring-mass, monopode model can approximate the energetics and dynamics of trotting, running, and hopping in animals as diverse as cockroaches, quail and kangaroos. From an animal's mechanical-energy fluctuation and ground-reaction force, we calculated the compression of a virtual monopode's leg and its stiffness. Comparison of dimensionless parameters revealed that locomotor dynamics depend on gait and leg number and not on body mass. Relative stiffness per leg was similar for all animals and appears to be a very conservative quantity in the design of legged locomotor systems. Differences in the general dynamics of gait are based largely on the number of legs acting simultaneously to determine the total stiffness of the system. Four- and six-legged trotters had a greater whole body stiffness than two-legged runners operating their systems at about the same relative speed. The greater whole body stiffness in trotters resulted in a smaller compression of the virtual leg and a higher natural frequency and stride frequency.

A comparison of energetics and ventilation of desert ants during voluntary and forced locomotion

THE energy cost of pedestrian locomotion in terrestrial vertebrates has been extensively studied1–3. Insects differ fundamentally from vertebrates, making data on their locomotion energetics of great comparative interest, but their small size and low behavioural plasticity complicate measurements. Miniature treadmills4–9 enforce unnatural running regimes; therefore no data exist on the energetics of insects running voluntarily, or on insect ventilation while running. We have now measured the minimum cost of transport and ventilation of the harvester ant Pogonomyrmex rugosus (mass, 17 mg) by using both treadmill and voluntary running. The minimum cost of transport was constant over temperature (34–43 °C) and lower than predicted from vertebrate data. Treadmill running significantly affected energetics, eliminating the slow ventilation (1–2 mm–1) in voluntarily running ants and substantially elevating extrapolated metabolic rate at zero running speed, which equalled the standard metabolic rate in voluntarily running ants.

Cost of tokking: the energetics of substrate communication in the tok-tok beetle,Psammodes striatus

Psammodes striatus, the ‘tok-tok’ beetle, communicates by substrate vibrations produced by tapping its abdomen on the ground. MaleP. striatus responded readily to computer-synthesized vibrations. Oxygen consumption rate (\(\dot V_{O_2 } \)) of individual male beetles (n=3; mean mass 3.01 g) was continually recorded by computer before, during and after tapping communication with the computer, which also counted the beetle's replies. Standard\(\dot V_{O_2 } \) of motionless beetles was also measured, during which time marked discontinuous ventilation was apparent. Since the relation between\(\dot V_{O_2 } \) and tapping rate was linear, it was possible to estimate net cost of tapping (0.0279 μl O2 g−1 tap−1) and minimum cost of tapping (0.0286 μl O2 g−1 tap−1). Kinematic analysis of trains of taps showed constant intertap period (ca. 150 ms) and distinctive amplitude modulation. The efficiency of muscular movement inP. striatus is 23% of metabolic input, assuming no elastic storage. This figure will drop to ca. 5–10% if significant elastic storage takes place. Minimum cost of searching for a mate via pedestrian locomotion is 340 J kg−1 m−2, but drops to 33 J kg−1 m−2 for tapping communication. Similar energetic ratios may play a role in the early stages of the evolution of some communication systems.

Visual control of locomotion.

Abstract.— How is locomotion controlled? What information is necessary and how is it used? It is first of all argued that the classical twofold division of information into ex‐teroceptive and proprioceptive is inadequate and confusing, that three fundamental types of information need to be distinguished and that the information is used in a continual process of formulating locomotor programs, monitoring their execution and adjusting them. The paper goes on to show (1) how steering could be controlled on the basis of the “locomotor flow line” in the optic array, which specifies the potential future course, whether curved or straight, and (2) how stopping for an obstacle could be controlled simply on the basis of the information in the optic array about the time‐to‐collision and its rate of change. The problems inherent in pedestrian locomotion of controlling footing and balance are discussed and an investigation of visual locomotor programming in the long jump reported.

Ignition of flammable gases and vapours by friction between footwear and flooring materials

For pedestrian locomotion, friction between footwear and flooring materials is necessary. What is not, perhaps, realised is that friction between two surfaces can produce temperatures approaching the lower of the melting points of the two materials. In circumstances where material is transferred from one surface to the other, temperatures near the higher melting point may be realised. Thus, with many everyday materials, temperatures approaching 1500° C are possible.Sparks are pieces of the hot surfaces ejected into the atmosphere. Those from materials that do not burn or oxidise in the atmosphere begin to cool as soon as they are formed. Certain materials, however, oxidise rapidly and their sparks can attain temperatures approaching 3000° C.Such hot surfaces or sparks produced in the vicinity of flammable gases or vapours can lead to fires and explosions.Tests of ‘hobnails’, tungsten carbide studs and ‘non-sparking’ materials, using a machine that can simulate a glancing kick, in flammable mixtures are described. Other materials that are used for footwear and flooring are discussed from the point of view of frictional ignition of gases and vapours.

The pace of life

THE specific effects of population pressure on the quality of everyday life should be of pressing social and policy concern; and although population studies have proliferated in the behavioural sciences, research has focused primarily on fertility-related behaviours1,2. Moreover, the few social scientists interested in the relationship of the numbers of humans to individual human behaviour have been puzzled by a dearth of clear-cut effects3. This study reports preliminary analyses from a larger cross-cultural investigation of the quality of life. Following a suggestion from Lowin et al.4, we have systematically observed the rates of pedestrian locomotion over a constant distance in 15 cities and towns in six countries in Europe, Asia and North America. The results of these observations indicate that pace of life varies in a regular fashion with the size of the local population, regardless of the cultural setting.

Effect of hyperthermia on heat balance during running in the African hunting dog.

ARTICLESEffect of hyperthermia on heat balance during running in the African hunting dogCR Taylor, K Schmidt-Nielsen, R Dmi'el, and M FedakCR Taylor, K Schmidt-Nielsen, R Dmi'el, and M FedakPublished Online:01 Mar 1971https://doi.org/10.1152/ajplegacy.1971.220.3.823MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByThe evolution of human fatigue resistance12 May 2022 | Journal of Comparative Physiology B, Vol. 192, No. 3-4Lycaon pictus (Carnivora: Canidae)9 April 2022 | Mammalian Species, Vol. 54, No. 1017Changes in Body Surface Temperature Associated with High-Speed Treadmill Exercise in Beagle Dogs Measured by Infrared Thermography15 October 2021 | Animals, Vol. 11, No. 10Are humans evolved specialists for running in the heat? Man vs . horse races provide empirical insights14 July 2020 | Experimental Physiology, Vol. 106, No. 1Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care in 201618 June 2020 | Scientific Reports, Vol. 10, No. 1Retrospective analysis of patient and environmental factors in heat-induced injury events in 103 military working dogsJournal of the American Veterinary Medical Association, Vol. 256, No. 7Comparative analyses of basal rate of metabolism in mammals: data selection does matter27 July 2017 | Biological Reviews, Vol. 93, No. 1The influence of thermal inputs on brain regulation of exercise: An evolutionary perspectiveHot dogs: High ambient temperatures impact reproductive success in a tropical carnivore19 July 2017 | Journal of Animal Ecology, Vol. 86, No. 6Phylogenetic comparisons of pedestrian locomotion costs: confirmations and new insights31 August 2016 | Ecology and Evolution, Vol. 6, No. 18Additive opportunistic capture explains group hunting benefits in African wild dogs29 March 2016 | Nature Communications, Vol. 7, No. 1Energy cost and return for hunting in African wild dogs and cheetahs29 March 2016 | Nature Communications, Vol. 7, No. 1Metabolic Scaling in Animals: Methods, Empirical Results, and Theoretical Explanations10 January 2014Exercise Physiology of the Canine AthleteThermographic Imaging of the Superficial Temperature in Racing Greyhounds before and after the RaceThe Scientific World Journal, Vol. 2012Is it Time to Retire the ‘Central Governor’?Sports Medicine, Vol. 39, No. 9Reappraisal of the comparative cost of human locomotion using gait-specific allometric analysesJournal of Experimental Biology, Vol. 210, No. 20Anticipatory regulation and avoidance of catastrophe during exercise-induced hyperthermiaComparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, Vol. 139, No. 4High hunting costs make African wild dogs vulnerable to kleptoparasitism by hyaenasNature, Vol. 391, No. 6666Limitation of Heat Tolerance1 January 2011Dependency of surface temperature regulation on body size in terrestrial mammalsJournal of Thermal Biology, Vol. 20, No. 3Were there mammalian pursuit predators in the tertiary? Dances with wolf avatarsJournal of Mammalian Evolution, Vol. 1, No. 2Thermal parameters of serval Felis serval (Felidae) and blackbacked jackal Canis mesomelas (Canidae)Journal of Thermal Biology, Vol. 16, No. 5Basal Rate of Metabolism, Body Size, and Food Habits in the Order CarnivoraThe loss of functional body hair in man: the influence of thermal environment, body form and bipedalityJournal of Human Evolution, Vol. 14, No. 1The evolution of bipedality and loss of functional body hair in hominidsJournal of Human Evolution, Vol. 13, No. 1Why Black Goats in Hot Deserts? Effects of Coat Color on Heat Exchanges of Wild and Domestic GoatsPhysiological Zoology, Vol. 53, No. 1Reappraisal of energetics of locomotion shows identical cost in bipeds and quadrupeds including ostrich and horseNature, Vol. 282, No. 5740Thermoregulation and Standard Metabolism of the Slender Mongoose (Herpestes sanguineus)Physiological Zoology, Vol. 52, No. 4Rapid Brain Cooling in Exercising DogsScience, Vol. 195, No. 4280Effect of Temperature on Metabolism during Running in the Lizard Uromastix aegyptiusPhysiological Zoology, Vol. 49, No. 1Environmental physiology of the banner-tailed kangaroo rat—I. Influences of ambient temperature, humidity and carbon dioxide on body temperatureComparative Biochemistry and Physiology Part A: Physiology, Vol. 50, No. 3EVOLUTION OF THERMOREGULATION More from this issue > Volume 220Issue 3March 1971Pages 823-827 Copyright & PermissionsCopyright © 1971 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1971.220.3.823PubMed5545695History Published online 1 March 1971 Published in print 1 March 1971 Metrics