scholarly journals Compliant leg behaviour explains basic dynamics of walking and running

2006 ◽  
Vol 273 (1603) ◽  
pp. 2861-2867 ◽  
Author(s):  
Hartmut Geyer ◽  
Andre Seyfarth ◽  
Reinhard Blickhan
Keyword(s):  
Mechanical System ◽  
Legged Locomotion ◽  
Human Locomotion ◽  
The Body ◽  
Phase Changes ◽  
Vertical Oscillation ◽  
Mass Model ◽  
Double Support ◽  
Walking Motion ◽  
The Many

The basic mechanics of human locomotion are associated with vaulting over stiff legs in walking and rebounding on compliant legs in running. However, while rebounding legs well explain the stance dynamics of running, stiff legs cannot reproduce that of walking. With a simple bipedal spring–mass model, we show that not stiff but compliant legs are essential to obtain the basic walking mechanics; incorporating the double support as an essential part of the walking motion, the model reproduces the characteristic stance dynamics that result in the observed small vertical oscillation of the body and the observed out-of-phase changes in forward kinetic and gravitational potential energies. Exploring the parameter space of this model, we further show that it not only combines the basic dynamics of walking and running in one mechanical system, but also reveals these gaits to be just two out of the many solutions to legged locomotion offered by compliant leg behaviour and accessed by energy or speed.

Validating Determinants for an Alternate Foot Placement Selection Algorithm During Human Locomotion in Cluttered Terrain

2007 ◽  
Vol 98 (4) ◽  
pp. 1928-1940 ◽  
Author(s):  
Renato Moraes ◽  
Fran Allard ◽  
Aftab E. Patla
Keyword(s):  
Dynamic Stability ◽  
Center Of Mass ◽  
Frontal Plane ◽  
Human Locomotion ◽  
The Body ◽  
Selection Algorithm ◽  
Foot Placement ◽  
Double Support ◽  
One Step ◽  
Base Of Support

The goal of this study was to validate dynamic stability and forward progression determinants for the alternate foot placement selection algorithm. Participants were asked to walk on level ground and avoid stepping, when present, on a virtual white planar obstacle. They had a one-step duration to select an alternate foot placement, with the task performed under two conditions: free (participants chose the alternate foot placement that was appropriate) and forced (a green arrow projected over the white planar obstacle cued the alternate foot placement). To validate the dynamic stability determinant, the distance between the extrapolated center of mass (COM) position, which incorporates the dynamics of the body, and the limits of the base of support was calculated in both anteroposterior (AP) and mediolateral (ML) directions in the double support phase. To address the second determinant, COM deviation from straight ahead was measured between adaptive and subsequent steps. The results of this study showed that long and lateral choices were dominant in the free condition, and these adjustments did not compromise stability in both adaptive and subsequent steps compared with the short and medial adjustments, which were infrequent and adversely affected stability. Therefore stability is critical when selecting an alternate foot placement in a cluttered terrain. In addition, changes in the plane of progression resulted in small deviations of COM from the endpoint goal. Forward progression of COM was maintained even for foot placement changes in the frontal plane, validating this determinant as part of the selection algorithm.

A Spring-Mass Model of Locomotion With Full Asymptotic Stability

2011 ◽  
Author(s):  
Zhuohua Shen ◽  
Justin Seipel
Keyword(s):  
Inverted Pendulum ◽  
Center Of Mass ◽  
Legged Locomotion ◽  
Human Locomotion ◽  
Whole Body ◽  
Slip Model ◽  
Mass Model ◽  
Energy Conserving ◽  
Spring Loaded Inverted Pendulum ◽  
Passive Model

The concept of passive dynamic walking and running [5] has demonstrated that a simple passive model can represent the dynamics of whole-body human locomotion. Since then, many passive models were developed and studied: [3,1,2,11]. The later developed Spring-Loaded Inverted Pendulum (SLIP) [1, 4, 11, 2] exhibits stable center of mass (CoM) motions just by resetting the landing angle at each touch down. Also, compared to SLIP, a SLIP-like model with simple flight leg control is better at resisting perturbations of the angle of velocity but not the magnitude [11, 2, 7]. Energy conserving models explain much about whole-body locomotion. Recently, there has been investigations of modified spring-mass models capable of greater stability, like that of animals and robots [9, 10, 8, 12]. Inspired by RHex [6], the Clock-Torqued Spring-Loaded Inverted Pendulum (CT-SLIP) model [9] was developed, and has been used to explain the robust stability of animal locomotion [12]. Here we present a model (mechanism) simpler than CT-SLIP called Forced-Damped SLIP (FD-SLIP) that can attain full asymptotically stability of the CoM during locomotion, and is capable of both walking and running motions. The FD-SLIP model, having fewer parameters, is more accessible and easier to analyze for the exploration and discovery of principles of legged locomotion.

scholarly journals Rate-dependent control strategies stabilize limb forces during human locomotion

2009 ◽  
Vol 7 (46) ◽  
pp. 801-810 ◽  
Author(s):  
Jasper T. Yen ◽  
Young-Hui Chang
Keyword(s):  
Control Strategies ◽  
Legged Locomotion ◽  
Human Locomotion ◽  
Joint Torque ◽  
Uncontrolled Manifold ◽  
Centre Of Mass ◽  
Mass Model ◽  
Joint Torques ◽  
Rate Dependent ◽  
Muscle Moments

A spring-mass model accurately predicts centre of mass dynamics for hopping and running animals and is pervasive throughout experimental and theoretical studies of legged locomotion. Given the neuromechanical complexity of the leg, it remains unclear how joint dynamics are selected to achieve such simple centre of mass movements consistently from step to step and across changing conditions. Human hopping is a tractable experimental model to study how net muscle moments, or joint torques, are coordinated for spring-mass dynamics, which include stable, or invariant, vertical ground forces. Subjects were equally able to stabilize vertical forces at all hopping frequencies (2.2, 2.8, 3.2 Hz) by selecting force-equivalent joint torque combinations. Using a hybrid-uncontrolled manifold permutation analysis, however, we discovered that force stabilization relies less on interjoint coordination at greater hopping frequencies and more on selection of appropriate ankle joint torques. We conclude that control strategies for selecting the joint torques that stabilize forces generated on the ground are adjusted to the rate of movement. Moreover, this indicates that legged locomotion may involve the differential regulation of several redundant motor control strategies that are accessed as needed to match changing environmental conditions.

scholarly journals Templates and anchors: neuromechanical hypotheses of legged locomotion on land

1999 ◽  
Vol 202 (23) ◽  
pp. 3325-3332 ◽  
Author(s):  
R.J. Full ◽  
D.E. Koditschek
Keyword(s):  
Mechanical System ◽  
Control Strategies ◽  
Legged Locomotion ◽  
Slow Variable ◽  
The Body ◽  
Physiological Models ◽  
Joint Torques ◽  
Diverse Species ◽  
Low Degree ◽  
The Neural Networks

Locomotion results from complex, high-dimensional, non-linear, dynamically coupled interactions between an organism and its environment. Fortunately, simple models we call templates have been and can be made to resolve the redundancy of multiple legs, joints and muscles by seeking synergies and symmetries. A template is the simplest model (least number of variables and parameters) that exhibits a targeted behavior. For example, diverse species that differ in skeletal type, leg number and posture run in a stable manner like sagittal- and horizontal-plane spring-mass systems. Templates suggest control strategies that can be tested against empirical data. Templates must be grounded in more detailed morphological and physiological models to ask specific questions about multiple legs, the joint torques that actuate them, the recruitment of muscles that produce those torques and the neural networks that activate the ensemble. We term these more elaborate models anchors. They introduce representations of specific biological details whose mechanism of coordination is of interest. Since mechanisms require controls, anchors incorporate specific hypotheses concerning the manner in which unnecessary motion or energy from legs, joints and muscles is removed, leaving behind the behavior of the body in the low-degree-of-freedom template. Locating the origin of control is a challenge because neural and mechanical systems are dynamically coupled and both play a role. The control of slow, variable-frequency locomotion appears to be dominated by the nervous system, whereas during rapid, rhythmic locomotion, the control may reside more within the mechanical system. Anchored templates of many-legged, sprawled-postured animals suggest that passive, dynamic self-stabilization from a feedforward, tuned mechanical system can reject rapid perturbations and simplify control. Future progress would benefit from the creation of a field embracing comparative neuromechanics.

Representing utility and deploying the body

2020 ◽  
Vol 43 ◽  
Author(s):  
David Spurrett
Keyword(s):  
Functional Activity ◽  
Degrees Of Freedom ◽  
The Body ◽  
Target Article ◽  
Processing Demands ◽  
The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

Study of the dynamics of ТПА 350 automatic mill working stand elements

2020 ◽  
Vol 76 (8) ◽  
pp. 830-840
Author(s):  
S. R. Rakhmanov ◽  
V. V. Povorotnii
Keyword(s):  
Mechanical System ◽  
Dynamic Model ◽  
Maximum Amplitude ◽  
Calculation Scheme ◽  
Dynamic Loads ◽  
Forced Oscillations ◽  
Mass Model ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Oscillation Movement

To form a necessary geometry of a hollow billet to be rolled at a pipe rolling line, stable dynamics of the base equipment of the automatic mill working stand has a practical meaning. Among the forces, acting on its parts and elements, significant by value short-time dynamic loads are the least studied phenomena. These dynamic loads arise during transient interaction of the hollow billet, rollers, mandrel and other mill parts at the forced grip of the hollow billet. Basing of the calculation scheme and dynamic model of the mechanical system of the ТПА 350 automatic mill working stand was accomplished. A mathematical model of dynamics of the system “hollow billet (pipe) – working stand” within accepted calculation scheme and dynamic model of the mechanical system elaborated. Influence of technological load of the rolled hollow billet variation in time was accounted, as well as variation of the mechanical system mass, and rigidity of the ТПА 350 automatic mill working stand. Differential equations of oscillation movement for four-mass model of forked sub-systems of the automatic mill working stand were made up, results of their digital calculation quoted. Dynamic displacement of the stand elements in the inter-roller gap obtained, which enabled to estimate the results of amplitude and frequency characteristics of the branches of the mill rollers setting. It was defined by calculation, that the maximum amplitude of the forced oscillations of elements of the ТПА 350 automatic mill working stand within the inter-roller gap does not exceed 2 mm. It is much higher than the accepted value of adjusting parameters of the deformation center of the ТПА 350 automatic mill. A scheme of comprehensive modernization of the rollers setting in the ТПА 350 automatic mill working stand was proposed. It was shown, that increase of rigidity of rollers setting in the ТПА 350 automatic mill working stand enables to stabilize the amplitude of forced oscillations of the working stand elements within the inter-rollers gap and considerably decrease the induced nonuniform hollow billet wall thickness and increase quality of the rolled pipes at ТПА 350.

Gendered Secularization and the Body Policing of Muslim Women

2018 ◽  
Author(s):  
Raissa Killoran
Keyword(s):  
Muslim Women ◽  
The State ◽  
The Body ◽  
Religious Expression ◽  
Women's Bodies ◽  
Cultural Symbols ◽  
Religious Symbols ◽  
Female Bodies ◽  
The Many ◽  
A Site

The many usages of the term ‘secularism’ have generated an ambiguity in the word; as a political guise, it may be used to engender anti-religious fervor. Particularly in regards to veiling among female Muslim adherents, the attainment of a secular state and touting of the necessity of dismantling religious symbols have functioned as linguistic shields. By calling a “burka ban” necessary or even egalitarian secularization, legislators employ ‘secularization’ as jargon for political ends, enacting a stance of supremacy under the semblance of progress. Secularization has come to function as a political tool - in the name of it, governments may prescribe which cultural symbols are normative and which are of ‘other’ cultures or religious origins. As such, the identification of some religious symbols as foreign and others as normative is a usage of secularization for normalization of dominant religious expression. In this, there is an implicit neocolonialism; by imposing standards of cultural normalcy which are definitively nonMuslim, such policies attempt to divorce Muslims from Islam.  Further, I intend to investigate the gendered aspect of secularization politics. By critiquing clothing and body policing of women, I will demonstrate how secularization projects use the female body and dress as a site for display. By rendering the female physically emblematic of the honor and virtue of an ‘other’ culture, those enacting secularization norms target women’s bodies to act as visual exhibitions of the dominant culture’s hegemony. Here, we see gendered secularization at work - female bodies become controlled by the antireligious zeal of the state, while the state carries out this control on the predicate that it is the religious group enacting unjust control. As such, the policing of female Muslim bodies is symbolic of the policing of Islam as a whole; it acts as an illustration of an imposed, gendered secularization project.

Anticipatory weight shift between arms when reaching from a crouched posture

2021 ◽  
Author(s):  
Rosemary Gallagher ◽  
Stephaine Perez ◽  
Derek DeLuca ◽  
Isaac L. Kurtzer
Keyword(s):  
Body Weight ◽  
Muscle Activity ◽  
Force Plate ◽  
Vertical Axis ◽  
The Body ◽  
Reaching Movements ◽  
Reactive Control ◽  
Step Initiation ◽  
Weight Shift ◽  
The Many

Reaching movements performed from a crouched body posture require a shift of body weight from both arms to one arm. This situation has remained unexamined despite the analogous load requirements during step initiation and the many studies of reaching from a seated or standing posture. To determine whether the body weight shift involves anticipatory or exclusively reactive control we obtained force plate records, hand kinematics, and arm muscle activity from 11 healthy right-handed participants. They performed reaching movements with their left and right arm in two speed contexts - 'comfortable' and 'as fast as possible' - and two postural contexts - a less stable knees-together posture and more stable knees-apart posture. Weight-shifts involved anticipatory postural actions (APA) by the reaching and stance arms that were opposing in the vertical axis and aligned in the side-to-side axis similar to APAs by the legs for step initiation. Weight-shift APAs were correlated in time and magnitude, present in both speed contexts, more vigorous with the knees placed together, and similar when reaching with the dominant or non-dominant arm. The initial weight-shift was preceded by bursts of muscle activity in the shoulder and elbow extensors (posterior deltoid and triceps lateral) of the reach arm and shoulder flexor (pectoralis major) of the stance arm which indicates their causal role; leg muscles may have indirectly contributed but were not recorded. The strong functional similarity of weight-shift APAs during crouched reaching to human stepping and cats reaching suggests that they are a core feature of posture-movement coordination.

scholarly journals Elastic energy savings and active energy cost in a simple model of running

2021 ◽  
Vol 17 (11) ◽  
pp. e1009608
Author(s):  
Ryan T. Schroeder ◽  
Arthur D. Kuo
Keyword(s):  
Elastic Energy ◽  
Energy Cost ◽  
Energy Savings ◽  
Mechanical Energy ◽  
Metabolic Cost ◽  
The Body ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Mass Model ◽  
Human Running

The energetic economy of running benefits from tendon and other tissues that store and return elastic energy, thus saving muscles from costly mechanical work. The classic “Spring-mass” computational model successfully explains the forces, displacements and mechanical power of running, as the outcome of dynamical interactions between the body center of mass and a purely elastic spring for the leg. However, the Spring-mass model does not include active muscles and cannot explain the metabolic energy cost of running, whether on level ground or on a slope. Here we add explicit actuation and dissipation to the Spring-mass model, and show how they explain substantial active (and thus costly) work during human running, and much of the associated energetic cost. Dissipation is modeled as modest energy losses (5% of total mechanical energy for running at 3 m s-1) from hysteresis and foot-ground collisions, that must be restored by active work each step. Even with substantial elastic energy return (59% of positive work, comparable to empirical observations), the active work could account for most of the metabolic cost of human running (about 68%, assuming human-like muscle efficiency). We also introduce a previously unappreciated energetic cost for rapid production of force, that helps explain the relatively smooth ground reaction forces of running, and why muscles might also actively perform negative work. With both work and rapid force costs, the model reproduces the energetics of human running at a range of speeds on level ground and on slopes. Although elastic return is key to energy savings, there are still losses that require restorative muscle work, which can cost substantial energy during running.

scholarly journals KARAKTERISTIK FISIK, KIMIA, DAN ORGANOLEPTIK MIE MOSAF (MODIFIED SATOIMO FLOUR) (Colocasia esculenta)

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Eliantosi ◽  
Darius
Keyword(s):  
Hyaluronic Acid ◽  
Wheat Flour ◽  
Consumer Preferences ◽  
Colocasia Esculenta ◽  
Fiber Content ◽  
The Body ◽  
Tolerance Level ◽  
Physical Chemical ◽  
Taro Flour ◽  
The Many

Satoimo rich in Hyaluronic Acid ( HA ) , a substance produced naturally in the body and produce natural collagen . Taro flour relatively smooth and easy to digest useful for the preparation of pastries , cakes , breads and noodles . Noodle is one of the many products that are favored by all the community . Has conducted research aimed to analyze the characteristics of the physical, chemical and organoleptic noodles mosaf ( Colocasia esculenta ) . The treatment is done in this study is a comparison of wheat flour : flour mosaf with variations 450 g : 50 g ; 400 g : 100 g ; 350 g : 150 g ; 300 g : 200 g ; and 250 g : 250 g . The analysis in this study includes the analysis of the fiber content , elasticity and organoleptic ( color, taste, texture dam ) mosaf wet noodle . The results showed that the higher concentration mosaf flour is added , then the noodles fiber content becomes higher but getting lower elasticity , whereas the level of consumer preferences of the parameters of color, flavor and texture of getting down , the tolerance level of the composition of wheat flour : 400 g flour mosaf : 100 g .Keywords : noodles , satoimo , mosaf 

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