Previous studies have shown that the motion intention recognition for lower limb prosthesis mainly focused on the identification of performed gait. However, the bionic prosthesis needs to know the next movement at the beginning of a new gait, especially in complex operation environments. In this paper, an upcoming locomotion prediction scheme via multilevel classifier fusion was proposed for the complex operation. At first, two motion states, including steady state and transient state, were defined. Steady-state recognition was backtracking of a (...) completed gait, which would be used as prior knowledge of motion prediction. In steady-state recognition, surface electromyographic and inertial sensors were fused to improve recognition accuracy; five typical locomotion modes were recognized by random forest classifier with over 97.8% accuracy. The transient state was defined as an observation period at the initial stage of upcoming movement, in which only the sEMG signal was recorded due to the limitation of sliding window length. LightGBM classifier was validated to outperform other methods in the accuracy and prediction time of transient-state recognition. Finally, a simplified HMM model based on prior knowledge and observation result was constructed to predict upcoming locomotion. The results indicated that the locomotion prediction was over 91% accuracy. The proposed scheme implements the locomotion prediction at the initial stage of each gait and provides critical information for the gait control of lower limb prosthesis. (shrink)

Three-legged animals do not exist today and such an animal is not found in the fossil record. Which constraints operate to result in the lack of a triped phenotype? Consideration of animal locomotion and robotic studies suggests that physical constraints would not prevent a triped from being functional or advantageous. As is reviewed here, the strongest constraint on the evolution of a triped is phylogenetic: namely, the early genetic adoption of a bilaterally symmetrical body plan occurring before the advent (...) of limbs. Presumably, this would greatly constrain any three-legged animal from ever evolving. Tripedalism is employed only by a few animals, but many use a tripod stance while engaged in a variety of activities. Because terms are often used interchangeably in the literature, a standardization of locomotion terminology is proposed. Understanding the constraints behind “forbidden” phenotypes forces us to confront gaps in our evolutionary understanding of which we may be unaware. (shrink)

The thoughts presented here never appeared in research proposals, but nevertheless grew at the Stanford University Artificial Intelligence Laboratory over the years 1971 through 1980 under support from the National Institutes of Health, the Defense Advanced Research Projects Agency, the National Science Foundation and the National Aeronautics and Space Administration, and more recently at the Carnegie-Mellon University Robotics Institute under Office of Naval Research contract number N00014-81-K-0503.

This paper presents a bioinspired lower extremity exoskeleton robot. The proposed exoskeleton robot can be adjusted in structure to meet the wearer’s height of 150–185 cm and has a good gait stability. In the gait control part, a method of identifying different locomotion modes is proposed; five common locomotion modes are considered in this paper, including sitting down, standing up, level-ground walking, ascending stairs, and descending stairs. The identification is depended on angle information of the hip, knee, and (...) ankle joints. A deep locomotion mode identification model based on long-short term memory architecture is proposed in this paper for exploiting the angle data. We conducted two experiments to verify the effectiveness of the proposed method. Experimental results show that the DLMIM is capable of learning inherent characteristics of joint angles and achieves more accurate identification than the other models. The last experiment demonstrates that the DLMIM can recognize transitions between different locomotion modes in time and the real-time performance varies with each individual. (shrink)

Shape and locomotion of tissue cells depend on the interaction of elements of the cytoskeleton, adhesion to the substrate and an intracellular hydrostatic pressure. The existence of this pressure becomes obvious from increase in cell volume on cessation of contractile forces and from observations with ultrasound acoustic microscopy. Wherever such an internal pressure is established, it is involved in generation of shape and driving force of cell locomotion. Therefore each hypothesis on cell shape and locomotion must consider (...) this property of a living cell. Apparently different types of locomotion depend on differences in substrate adhesion and/or cytoskeleton organisation. (shrink)

This paper focuses on an understudied aspect of Hobbes's natural philosophy: his approach to the domain of life. I concentrate on the role assigned by Hobbes to the heart, which occupies a central role in both his account of human physiology and of the origin of animal locomotion. With this, I have three goals in mind. First, I aim to offer a cross-section of Hobbes's effort to provide a mechanistic picture of human life. Second, I aim to contextualize Hobbes's (...) views in the seventeenth-century debates on human physiology and animal locomotion. In particular, I will compare Hobbes's views with the theories put forth by Harvey, Descartes, the Galenic, and Peripatetic traditions. Also, I will show that Hobbes was receptive to advances within contemporary English physiology and chemistry. Third, by means of a comparison with Descartes, I advance some hypothesis to explain why Hobbes indentified the heart, and not the brain (as was increasingly com... (shrink)

The lambda model predicts that the command received by each motor nucleus during locomotion is specific for the joint at which its muscle acts and is independent of external conditions. However, investigation of the commands received by motor nuclei during fictive locomotion and of the sensitivity of these commands to feedback from the limb during locomotion indicates that neither condition is satisfied.

Malgré leurs divergences, les interprètes sont en général d’accord sur le fait que pour Aristote, le lieu est bidimensionnel et peu significatif du point de vue de l’ontologie. Dernièrement, ces présupposés ont cependant été remis en question par Casey et Lang. Dans cet article, c’est la position traditionnelle qui est défendue, et j’argumente en faveur de l’idée qu’Aristote développe sa théorie du lieu à partir du point de vue d’une mécanique du mouvement spatial et des outils nécessaires à un corps (...) organique pour son mouvement dans l’espace – et non à partir d’une théorie de la localisation des corps. Pour finir, la méthodologie aristotélicienne est comparée avec la physique contemporaine depuis Descartes. (shrink)

Features of gait are determined at multiple levels, from the selection of the gait itself (e.g. walk or run) through the specific parameters utilized (stride length, frequency, etc.) to the pattern of muscular excitation. The ultimate choices are neurally determined, but what is involved with that decision process? Human locomotion appears stereotyped not so much because the pattern is predetermined, but because these movement patterns are good solutions for providing movement utilizing the machinery available to the individual (the legs (...) and their requisite components). Under different circumstances the appropriate solution may differ broadly (different gait) or subtly (different parameters). Interpretation of the neural decision making process would benefit from understanding the influences that determine the selection of the appropriate solution in any set of circumstances, including that of normal conditions. In this review we survey an array of studies that point to energetic cost as a key input to the gait coordination system, and not just an outcome of the gait pattern implemented. We then use that information to rigorously define the construct proposed by Sparrow and Newell (1998) where the effects of environment, organism and task act as constraints determining the solution set available, and the coordination pattern is then implemented under a pressure for energetic economy. Environment is defined in terms of affordances based on the ecological psychology definition of the concept and organism is defined as classic morphology and physiology based capabilities. We rely on a novel conceptualization of task that recognizes that the task goal needs to be separated from the mechanisms that achieve the goal if the motivation behind the selection of the mechanism strategy is to be exposed and understood. This reformulation of the Sparrow and Newell construct is then linked to the proposed pressure for economy by considering it as an optimization problem, where the most readily selected gait strategy will be that which achieves the task goal at (or near) the energetic minimum. (shrink)

The standard explanation for the origin of bilateral symmetry is that it conferred an advantage over radial symmetry for directed locomotion. However, recent developmental and phylogenetic studies suggest that bilateral symmetry may have evolved in a sessile benthic animal, predating the origin of directed locomotion. An evolutionarily feasible alternative explanation is that bilateral symmetry evolved to improve the efficiency of internal circulation by affecting the compartmentalization of the gut and the location of major ciliary tracts. This functional design (...) principle is illustrated best by the phylum Cnidaria where symmetry varies from radial to tetraradial, biradial and bilateral. In the Cnidaria, bilateral symmetry is manifest most strongly in the internal anatomy and the disposition of ciliary tracts. Furthermore, the bilaterally symmetrical Cnidaria are typically sessile and, in those bilaterally symmetrical cnidarians that undergo directed locomotion, the secondary body axis does not bear a consistent orientation to the direction of locomotion as it typically does in Bilateria. Within the Cnidaria, the hypothesized advantage of bilateral symmetry for internal circulation can be tested by experimental analysis and computer modeling of fluid mechanics. The developmental evolution of symmetry within the Cnidaria can be further explored through comparative gene expression studies among species whose symmetry varies. BioEssays 27:1174–1180, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

Summary The addition of ‘fire’ to the European battle repertoire resulted in the close-order drill for manoeuvres of the line. Begun in late sixteenth-century Netherlands and perfected in eighteenth-century Prussia under Frederick the Great, the drill's precision marching evolved into a military science which conceived what infantry acquired through rigorous training as a lawful ‘second nature’ of men. In contrast, the liberal Webers' 1836 locomotion research orientation was, as was that of French skirmishing, one of natural self-regulation. Later Prussian (...) military science, restored in Imperial Germany, was merged into locomotion science. (shrink)

The bacterial pathogen Listeria monocytogenes displays the remarkable ability to reorganize the actin cytoskeleton within host cells as a means for promoting cell‐to‐cell transfer of the pathogen, in a manner that evades humoral immunity. In a series of events commencing with the biosynthesis of the bacterial surface protein ActA, host cell actin and many actin‐associated protein self‐assemble to from rocket‐tail structures that continually grow at sites proximal to the bacterium and depolymerize distally. Widespread interest in the underlying molecular mechanism of (...) Listeria locomotion stems from the likelihood that the dynamic remodeling of the host cell actin cytoskeleton at the cell's leading edge involves mechanistically analogous interactions. Recent advances in our understanding of these fundamental cytoskeletal rearrangements have been achieved through a clearer recognition of the central role of oligo‐proline sequence repeats present in ActA, and these findings provide a basis for inferring the role of analogous host cell proteins in the force‐producing and position‐securing steps in pseudopod and lamellipod formation at the peripheral membrane. (shrink)

Duas das principais controvérsias que têm ocupado aqueles que se dedicam à teoria aris- totélica do movimento animal são a controvérsia acerca da forma da cognição através da qual um animal irracional apreende um objeto como um objeto de desejo e a controvérsia acerca da função desempenhada pela cognição na explicação aristotélica dos movimentos voluntários de locomoção animal. Neste artigo, eu apresento uma teoria acerca das formas como o desejo e a cognição se articulam na teoria aristotélica segundo a qual (...) um animal irracional apreende um objeto como um objeto de desejo através da percepção incidental deste objeto e, ao contrário do que a maioria parece acreditar, esta percepção não tem sempre a mesma função na produção destes movimentos. Se o que for dito aqui estiver correto, em alguns casos esta percepção é responsável tanto pela geração do desejo quan- to pela sua orientação, mas em outros ela é responsável apenas pela sua orientação. (shrink)