Analyzing Bounding and Galloping Using Simple Models

2008 ◽  
Vol 1 (1) ◽  
Author(s):  
Kenneth J. Waldron ◽  
J. Estremera ◽  
Paul J. Csonka ◽  
S. P. N. Singh
Keyword(s):  
Energy Loss ◽  
Stance Phase ◽  
Center Of Mass ◽  
Gait Pattern ◽  
Simulation Studies ◽  
Empirical Observation ◽  
Gait Characteristics ◽  
Hidden Symmetry ◽  
Study Results ◽  
Pitch Moment

This paper focuses on modeling the gait characteristics of a quadrupedal gallop. There have been a number of studies of the mechanics of the stance phase in which a foot is in contact with the ground. We seek to put these studies in the context of the stride, or overall motion cycle. The model used is theoretical, and is kept simple in the interest of transparency. It is compared to empirical data from observations of animals, and to data from experiments with robots such as our KOLT machine, and results from sophisticated simulation studies. Modeling of the energy loss inherent in the interaction between the system and the environment plays a key role in the study. Results include the discovery of a hidden symmetry in the gait pattern, usually regarded as being completely asymmetrical. Another result demonstrates that the velocities with which the two front feet impact and leave the ground are different, and similarly for the rear feet. The velocities of the foot pairs mirror each other. This is consistent with empirical observation, but is at variance with the assumption used almost universally when modeling stance. A further result elicits the importance of the pitch moment of inertia and other effects that make the mammalian architecture, in which the center of mass is closer to the shoulders than to the hips, beneficial..

scholarly journals Hardware-in-the-Loop Test of a Prosthetic Foot

2021 ◽  
Vol 11 (20) ◽  
pp. 9492
Author(s):  
Christina Insam ◽  
Lisa-Marie Ballat ◽  
Felix Lorenz ◽  
Daniel Jean Rixen
Keyword(s):  
Development Process ◽  
Test Bench ◽  
Center Of Mass ◽  
Gait Pattern ◽  
Hardware In The Loop ◽  
Prosthetic Foot ◽  
Gait Characteristics ◽  
Fundamental Investigation ◽  
Reaction Forces ◽  
Future Work

For a targeted development process of foot prostheses, a profound understanding of the dynamic interaction between humans and prostheses is necessary. In engineering, an often employed method to investigate the dynamics of mechanical systems is Hardware-in-the-Loop (HiL). This study conducted a fundamental investigation of whether HiL could be an applicable method to study the dynamics of an amputee wearing a prosthesis. For this purpose, a suitable HiL setup is presented and the first-ever HiL test of a prosthetic foot performed. In this setup, the prosthetic foot was tested on the test bench and coupled in real-time to a cosimulation of the amputee. The amputee was modeled based on the Virtual Pivot Point (VPP) model, and one stride was performed. The Center of Mass (CoM) trajectory, the Ground Reaction Forces (GRFs), and the hip torque were qualitatively analyzed. The results revealed that the basic gait characteristics of the VPP model can be replicated in the HiL test. Still, there were several limitations in the presented HiL setup, such as the limited actuator performance. The results implied that HiL may be a suitable method for testing foot prostheses. Future work will therefore investigate whether changes in the gait pattern can be observed by using different foot prostheses in the HiL test.

Gait Characteristics in Youth With Transverse Myelitis

2021 ◽  
Vol 27 (3) ◽  
pp. 38-48
Author(s):  
Miriam Hwang ◽  
Ann Flanagan ◽  
Adam Graf ◽  
Karen M. Kruger ◽  
Nancy Scullion ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Transverse Myelitis ◽  
Gait Pattern ◽  
Functional Mobility ◽  
Control Group ◽  
Typically Developing ◽  
Gait Characteristics ◽  
Foot Progression Angle ◽  
Study Results ◽  
Gait Deviation Index

Background: Transverse myelitis (TM) in childhood is a rare disorder characterized by the presence of spinal cord inflammation. Gait difficulty in children with TM is common; however, there is a paucity of literature regarding quantitative assessment of gait in children and adolescents with TM. Objectives: To characterize gait patterns in a cohort of ambulatory children with TM and age-matched, typically developing peers in order to better understand the functional mobility of patients diagnosed with childhood TM. Methods: This was a retrospective study of 26 ambulatory pediatric patients with a confirmed diagnosis of TM who had undergone three-dimensional, instrumented gait analysis (3D-IGA) at 3 years of age or older. A group of 38 typically developing children served as a control group. Results: Gait in children with TM was characterized by moderate kinematic deviations as measured by the Gait Deviation Index (GDI) and a crouched gait pattern (p < .001), increased anterior pelvic tilt (p < .001), decreased motion at the knees (p < .001), and a wider base of support (foot progression angle, p < .001). The TM group had a slower walking speed (p < .001), shorter strides (p < .001), and an increased stance phase compared to controls. Conclusion: Our study results showed moderate kinematic deviations quantified by the GDI. Overall, the gait pattern in the TM population tested had greater hip and knee flexion with wider foot progression angle. Identification of gait characteristics in children with TM is the first step in predicting changes in gait pattern as they mature over time, which may ultimately allow for targeted intervention to maintain their ambulatory function.

scholarly journals Vertical Jumping for Legged Robot Based on Quadratic Programming

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3679
Author(s):  
Dingkui Tian ◽  
Junyao Gao ◽  
Xuanyang Shi ◽  
Yizhou Lu ◽  
Chuzhao Liu
Keyword(s):  
Quadratic Programming ◽  
Stance Phase ◽  
Center Of Mass ◽  
Maximum Error ◽  
Legged Robot ◽  
Flight Phase ◽  
Programming Framework ◽  
Vertical Jumping ◽  
Control Schemes ◽  
And Control

The highly dynamic legged jumping motion is a challenging research topic because of the lack of established control schemes that handle over-constrained control objectives well in the stance phase, which are coupled and affect each other, and control robot’s posture in the flight phase, in which the robot is underactuated owing to the foot leaving the ground. This paper introduces an approach of realizing the cyclic vertical jumping motion of a planar simplified legged robot that formulates the jump problem within a quadratic-programming (QP)-based framework. Unlike prior works, which have added different weights in front of control tasks to express the relative hierarchy of tasks, in our framework, the hierarchical quadratic programming (HQP) control strategy is used to guarantee the strict prioritization of the center of mass (CoM) in the stance phase while split dynamic equations are incorporated into the unified quadratic-programming framework to restrict the robot’s posture to be near a desired constant value in the flight phase. The controller is tested in two simulation environments with and without the flight phase controller, the results validate the flight phase controller, with the HQP controller having a maximum error of the CoM in the x direction and y direction of 0.47 and 0.82 cm and thus enabling the strict prioritization of the CoM.

Simple Leg Placement Strategy for a One Legged Running Model

2012 ◽  
Author(s):  
Timothy Sullivan ◽  
Justin Seipel
Keyword(s):  
Stance Phase ◽  
Energy State ◽  
Center Of Mass ◽  
Mass Movement ◽  
Legged Locomotion ◽  
Energy Conserving ◽  
Lower Torque ◽  
The Stability ◽  
Time Required ◽  
Torque Values

The Spring Loaded Inverted Pendulum (SLIP) model was developed to describe center of mass movement patterns observed in animals, using only a springy leg and a point mass. However, SLIP is energy conserving and does not accurately represent any biological or robotic system. Still, this model is often used as a foundation for the investigation of improved legged locomotion models. One such model called Torque Damped SLIP (TD-SLIP) utilizes two additional parameters, a time dependent torque and dampening to drastically increase the stability. Forced Damped SLIP (FD-SLIP), a predecessor of TD-SLIP, has shown that this model can be further simplified by using a constant torque, instead of a time varying torque, while still maintaining stability. Using FD-SLIP as a base, this paper explores a leg placement strategy using a simple PI controller. The controller takes advantage of the fact that the energy state of FD-SLIP is symmetric entering and leaving the stance phase during steady state conditions. During the flight phase, the touch down leg angle is adjusted so that the energy dissipation due to dampening, during the stance phase, compensates for any imbalance of energy. This controller approximately doubles the region of stability when subjected to velocity perturbations at touchdown, enables the model to operate at considerably lower torque values, and drastically reduces the time required to recover from a perturbation, while using less energy. Finally, the leg placement strategy used effectively imitates the natural human response to velocity perturbations while running.

Dynamic and Reactive Walking for Humanoid Robots Based on Foot Placement Control

2016 ◽  
Vol 13 (02) ◽  
pp. 1550041 ◽  
Author(s):  
Juan Alejandro Castano ◽  
Zhibin Li ◽  
Chengxu Zhou ◽  
Nikos Tsagarakis ◽  
Darwin Caldwell
Keyword(s):  
Center Of Mass ◽  
Humanoid Robots ◽  
Gait Pattern ◽  
Gait Patterns ◽  
Foot Placement ◽  
Inverted Pendulum Model ◽  
Gait Parameters ◽  
Pendulum Model ◽  
Single Mass ◽  
Walking Velocity

This paper presents a novel online walking control that replans the gait pattern based on our proposed foot placement control using the actual center of mass (COM) state feedback. The analytic solution of foot placement is formulated based on the linear inverted pendulum model (LIPM) to recover the walking velocity and to reject external disturbances. The foot placement control predicts where and when to place the foothold in order to modulate the gait given the desired gait parameters. The zero moment point (ZMP) references and foot trajectories are replanned online according to the updated foothold prediction. Hence, only desired gait parameters are required instead of predefined or fixed gait patterns. Given the new ZMP references, the extended prediction self-adaptive control (EPSAC) approach to model predictive control (MPC) is used to minimize the ZMP response errors considering the acceleration constraints. Furthermore, to ensure smooth gait transitions, the conditions for the gait initiation and termination are also presented. The effectiveness of the presented gait control is validated by extensive disturbance rejection studies ranging from single mass simulation to a full body humanoid robot COMAN in a physics based simulator. The versatility is demonstrated by the control of reactive gaits as well as reactive stepping from standing posture. We present the data of the applied disturbances, the prediction of sagittal/lateral foot placements, the replanning of the foot/ZMP trajectories, and the COM responses.

scholarly journals Biomechanical parameters characterising the foot during normal gait

2021 ◽  
Vol 21 (2) ◽  
pp. 87-104
Author(s):  
Arina SEUL ◽  
Aura MIHAI ◽  
Antonela CURTEZA ◽  
Mariana COSTEA ◽  
Bogdan SÂRGHIE
Keyword(s):  
Neuromuscular Control ◽  
Gait Pattern ◽  
Biomechanical Analysis ◽  
Human Gait ◽  
Foot Health ◽  
Mean Values ◽  
Study Results ◽  
Size Groups ◽  
Biomechanical Parameters ◽  
Extended Group

The biomechanical analysis allows to understand the normal and pathological gait, the mechanics of neuromuscular control, and last but not least, allows the visualisation of the effects of footwear on human gait or feet. Biomechanical analyses are very important for the footwear development process, as they can identify the incorrect loading of the foot or the incorrect gait pattern, thus avoiding the occurrence of deformations. This paper aims to create an average representative model of barefoot loading based on an extended group of participants by applying an optimal procedure for measuring biomechanical parameters. The variation of four basic biomechanical parameters, namely force, pressure, contact time and contact area, was measured using a pressure platform and a specialised software system. The data was collected from 32 healthy females, without particularities regarding foot health and the practice of performance sports, aged between 18 and 30 years, divided into three size groups – 36, 37 and 38. The T-Student test was applied to verify if there are significant differences between the left and right foot. Statistical indicators for each parameter were calculated, in order to characterize and establish the degree of variation of the obtained values, as follows: mean, standard deviation, minimum and maximum values, the amplitude of variation and coefficient of variation (CV). The study results confirm that the obtained mean values can be used as input data to load the foot and perform virtual simulations of footwear products.

scholarly journals Dynamic Balancing Responses in Unilateral Transtibial Amputees Following Outward-Directed Perturbations During Slow Treadmill Walking Differ Considerably for Amputated and Non-Amputated Side

2021 ◽  
Author(s):  
Andrej Olenšek ◽  
Matjaž Zadravec ◽  
Helena Burger ◽  
Zlatko Matjačić
Keyword(s):  
Stance Phase ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Reaction Force ◽  
Dynamic Balancing ◽  
Transtibial Amputation ◽  
Control Subjects ◽  
Foot Strike ◽  
Transtibial Amputees ◽  
Proprioceptive Function

Abstract BackgroundDue to disrupted motor and proprioceptive function lower limb amputation imposes considerable challenges associated with balance and greatly increases risk of falling in case of perturbations during walking. The aim of this study was to investigate dynamic balancing responses in unilateral transtibial amputees when they were subjected to perturbing pushes to the pelvis in outward direction at the time of foot strike on non-amputated and amputated side during slow walking.MethodsFourteen subjects with unilateral transtibial amputation and nine control subjects participated in the study. They were subjected to perturbations that were delivered to the pelvis at the time of foot strike of either the left or right leg. We recorded trajectories of center of pressure and center of mass, durations of in-stance and stepping periods as well as ground reaction forces. Statistical analysis was performed to determine significant differences in dynamic balancing responses between control subjects and subjects with amputation when subjected to outward-directed perturbation upon entering stance phases with non-amputated or amputated side.ResultsWhen outward-directed perturbations were delivered at the time of foot strike of the non-amputated leg, subjects with amputation were able to modulate center of pressure and ground reaction force similarly as control subjects which indicates application of in-stance balancing strategies. On the other hand, there was a complete lack of in-stance response when perturbations were delivered when the amputated leg entered the stance phase. Subjects with amputations instead used the stepping strategy and adjusted placement of the non-amputated leg in the ensuing stance phase to make a cross-step. Such response resulted in significantly higher displacement of center of mass. ConclusionsResults of this study suggest that due to the absence of the COP modulation mechanism, which is normally supplied by ankle motor function, people with unilateral transtibial amputation are compelled to choose the stepping strategy over in-stance strategy when they are subjected to outward-directed perturbation on the amputated side. However, the stepping response is less efficient than in-stance response. To improve their balancing responses to unexpected balance perturbation people fitted with passive transtibial prostheses should undergo perturbation-based balance training during clinical rehabilitation.

Long bone cross-sectional geometry

2020 ◽  
pp. 307-320
Author(s):  
Christopher B. Ruff ◽  
Ryan W. Higgins ◽  
Kristian J. Carlson
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Lateral Displacement ◽  
Center Of Mass ◽  
Gait Pattern ◽  
Locomotor Behavior ◽  
The Body ◽  
Long Bone ◽  
Cross Sectional ◽  
Body Center

Long bone diaphyseal cross-sectional geometries reflect the mechanical properties of the bones, and can be used to aid in inferences of locomotor behavior in extinct hominins. This chapter considers all available long bone diaphyseal and femoral neck cross-sections of specimens from Sterkfontein Member 4, and presents comparisons of these section properties and other cross-sectional dimensions with those of other early hominins as well as modern samples. The cross-sectional geometry of the Sterkfontein Member 4 long bone specimens suggests some similarities to, but also interesting differences in, mechanical loading of these elements relative to modern humans. The less asymmetric cortical bone distribution in the Sterkfontein femoral necks is consistent with other evidence above indicating an altered gait pattern involving lateral displacement of the body center of mass over the stance limb. The relatively very strong upper limb of StW 431 implies that arboreal behavior formed a significant component of its locomotor repertoire. Bipedal gait may have been less efficient and arboreal climbing more prevalent in the Sterkfontein hominins.

Adding Light Touch While Walking in Older Adults: Biomechanical and Neuromotor Effects

2020 ◽  
Vol 28 (5) ◽  
pp. 680-685
Author(s):  
Alison R. Oates ◽  
Aaron Awdhan ◽  
Catherine Arnold ◽  
Joyce Fung ◽  
Joel L. Lanovaz
Keyword(s):  
Older Adults ◽  
Muscle Activity ◽  
Balance Control ◽  
Center Of Mass ◽  
Gait Pattern ◽  
Light Touch ◽  
Margin Of Stability ◽  
Complex Picture ◽  
Falls In Older Adults ◽  
Haptic Input

Adding haptic input may improve balance control and help prevent falls in older adults. This study examined the effects of added haptic input via light touch on a railing while walking. Participants (N = 53, 75.9 ± 7.9 years) walked normally or in tandem (heel to toe) with and without haptic input. During normal walking, adding haptic input resulted in a more cautious and variable gait pattern, reduced variability of center of mass acceleration and margin of stability, and increased muscle activity. During tandem walking, haptic input had minimal effect on step parameters, decreased lower limb muscle activity, and increased cocontraction at the ankle closest to the railing. Age was correlated with step width variability, stride length variability, stride velocity, variability of medial-lateral center of mass acceleration, and margin of stability for tandem walking. This complex picture of sensorimotor integration in older adults warrants further exploration into added haptic input during walking.

Mobility Characteristics of Children with Spastic Paraplegia Due to a Mutation in the KIF1A Gene

2019 ◽  
Vol 51 (02) ◽  
pp. 146-153 ◽  
Author(s):  
A.E. Van Beusichem ◽  
J. Nicolai ◽  
J. Verhoeven ◽  
L. Speth ◽  
M. Coenen ◽  
...  
Keyword(s):  
De Novo ◽  
Gait Pattern ◽  
Secondary Development ◽  
Spastic Paraplegia ◽  
Patients Âgés ◽  
Gait Characteristics ◽  
Abnormal Gait ◽  
Complicated Form ◽  
Crouch Gait

AbstractSeveral de novo variants in the KIF1A gene have been reported to cause a complicated form of hereditary spastic paraplegia. Additional symptoms include cognitive impairment and varying degrees of peripheral neuropathy, epilepsy, decreased visual acuity, and ataxia. We describe four patients (ages 10–18 years), focusing on their mobility and gait characteristics. Two patients were not able to walk without assistance and showed a severe abnormal gait pattern, crouch gait. At examination, severe contractures were found.In addition to describing the different phenotypes with specific attention to gait in our cases, we reviewed known KIF1A mutations and summarized their associated phenotypes.We conclude that mobility and cognition are severely affected in children with spastic paraplegia due to de novo KIF1A mutations. Deterioration in mobility is most likely due to progressive spasticity, muscle weakness, and the secondary development of severe contractures, possibly combined with an additional progressive polyneuropathy. Close follow-up and treatment of these patients are warranted.

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