Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability

Perry, Jennifer A.; Srinivasan, Manoj

doi:10.1098/rsos.160627

Cited by 60 publications

(104 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Instead, the perturbation experiments have only been used to obtain insights into limited aspects of walking control such as foot placement or centre of pressure modulation [5,7,[15][16][17][18], ankle impedance [12,19], impulse response functions for some muscles [14,15] or some aspect of body motion [9]. Other authors have considered natural step-to-step variability in unperturbed steady-state locomotion [10,[20][21][22][23][24] to obtain information about stability and control of walking and running, but again, we do not know of a complete synthesis of a walking controller from such measurements. Similarly, there have been many stable bipedal walking simulations [25][26][27][28], stable two-legged walking robots [29,30], and robotic prostheses and exoskeletons [31,32], but none of these simulations, robots or assistive devices have controllers that are quantitatively derived from human walking response to perturbations.…”

Section: Introductionmentioning

confidence: 99%

A controller for walking derived from how humans recover from perturbations

Joshi

Srinivasan

2019

J. R. Soc. Interface.

Self Cite

View full text Add to dashboard Cite

Humans can walk without falling despite some external perturbations, but the control mechanisms by which this stability is achieved have not been fully characterized. While numerous walking simulations and robots have been constructed, no full-state walking controller for even a simple model of walking has been derived from human walking data. Here, to construct such a feedback controller, we applied thousands of unforeseen perturbations to subjects walking on a treadmill and collected data describing their recovery to normal walking. Using these data, we derived a linear controller to make the classical inverted pendulum model of walking respond to perturbations like a human. The walking model consists of a point-mass with two massless legs and can be controlled only through the appropriate placement of the foot and the push-off impulse applied along the trailing leg. We derived how this foot placement and push-off impulse are modulated in response to upper-body perturbations in various directions. This feedback-controlled biped recovers from perturbations in a manner qualitatively similar to human recovery. The biped can recover from perturbations over twenty times larger than deviations experienced during normal walking and the biped’s stability is robust to uncertainties, specifically, large changes in body and feedback parameters.

show abstract

Section: Introductionmentioning

confidence: 99%

A controller for walking derived from how humans recover from perturbations

Joshi

Srinivasan

2019

J. R. Soc. Interface.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The CNS actively stabilizes frontal plane motion by predicting future centre of mass position and altering foot placement to preserve a sufficient medial-lateral margin of stability 24 , 26 – 28 . The introduction of an additional degree-of-freedom, through the oscillation of a carried mass, could alter the body’s ability to predict centre of mass state; where the centre of mass state has been shown to be a predictor of step placement during locomotion 29 , 30 . In addition, humans are particularly sensitive to the application of non-steady state, random, perturbations during gait in the medial-lateral direction, as opposed to the fore-aft direction 31 , 32 .…”

Section: Introductionmentioning

confidence: 99%

Altering Compliance of a Load Carriage Device in the Medial-Lateral Direction Reduces Peak Forces While Walking

Martin

2018

Sci Rep

View full text Add to dashboard Cite

Altering mechanical compliance in load carriage structures has shown to reduce metabolic cost and accelerative forces of carrying weight. Currently, modifications to load carriage structures have been primarily targeted at vertical motion of the carried mass. No study to date has investigated altering load carriage compliance in the medial-lateral direction. We developed a backpack specifically for allowing a carried mass to oscillate in the horizontal direction, giving us the unique opportunity to understand the effects of lateral mass motion on human gait. Previous modelling work has shown that walking economy can be improved through the interaction of a bipedal model with a laterally oscillating walking surface. To test whether a laterally oscillating mass can experimentally improve walking economy, we systematically varied step width above and below the preferred level and compared the effects of carrying an oscillating and fixed mass. Walking with an oscillating mass was found to reduce the accelerative forces of load carriage in both horizontal and vertical directions. However, load eccentricity caused the vertical force component to create a significant bending moment in the frontal plane. Walking with an oscillating mass led to an increase in the metabolic energy expenditure during walking and an increase in positive hip work during stance. The device’s ability to reduce forces experienced by the user, due to load carriage, holds promise. However, the requirement of additional metabolic energy to walk with the device requires future study to improve.

show abstract

“…In all of the above-mentioned studies, the manipulability was not investigated by looking at the real human behavior. Given the recent interest in foot placement based stability analysis [30,39], it seems that an experimental analysis of manipulability of human walking could be of great interest for those studying human and humanoids gait stability. However, as discussed above, little is still known about the following: (a) variation of the manipulability of the swing limbs of human during walking, (b) the effect walking speed on the manipulability of swing foot, (c) variation of the manipulability of CoM and its correlation with stability, and (d) relation between the manipulability and local and orbital stability of walking.…”

Section: Introductionmentioning

confidence: 99%

On the manipulability of swing foot and stability of human locomotion

Fard

Bruijn

2019

Multibody Syst Dyn

View full text Add to dashboard Cite

Manipulability is a measure that quantifies the range of possible motions of a robotic end-effector and it is also an important measure in the study of coordination of human upper body and grasping tasks. This measure, which is defined on both the kinematic and dynamic level, could be useful in gait, as it could be used to determine potential foot placement possibilities. Kinematic manipulability is defined based on the Jacobian and dynamic manipulability on both the Jacobian and mass-inertia matrix. The main purpose of this study was to evaluate the manipulability of human walking and to explore a possible relation between the manipulability and dynamic stability of walking at different speeds. A 37-DoF tree-like model of the human body was developed to evaluate the manipulability index of human walking. We measured kinematics of 11 healthy male subjects while walking on a treadmill, and mapped the data to the model using inverse kinematics. Jacobian based kinematic/dynamic manipulability measures of walking were evaluated for the swing phase of walking. Manipulability ellipsoids were drawn for geometric determination of this measure in all directions during early, mid-and late swing phases. As stability metrics, the local divergence exponent and Floquet Multipliers were calculated. The results indicated a high kinematic manipulability of the swing foot during early and late swing phases and a drop in kinematic manipulability during mid-swing. Kinematic manipulability of the swing leg during early and late (but not mid-) swing phases increased with walking speed but the average kinematic manipulability of the center of mass and dynamic manipulability of swing foot decreased with increasing walking speed. Moreover, the results showed a weak relation between the manipulability and local and orbital stability.

show abstract

Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability

Cited by 60 publications

References 31 publications

A controller for walking derived from how humans recover from perturbations

A controller for walking derived from how humans recover from perturbations

Altering Compliance of a Load Carriage Device in the Medial-Lateral Direction Reduces Peak Forces While Walking

On the manipulability of swing foot and stability of human locomotion

Contact Info

Product

Resources

About