scholarly journals Instantaneous on-line modification of biped walk composed from reconfigurable adaptive motion primitives

2016 ◽  
Vol 20 (suppl. 2) ◽  
pp. 513-523
Author(s):  
Branislav Borovac ◽  
Mirko Rakovic
Keyword(s):  
Walking Speed ◽  
Step Length ◽  
Motion Primitives ◽  
Adaptive Motion ◽  
On Line ◽  
Simulation Results

The paper presents development and potentials of a novel methodology for biped walk synthesis based on motion primitives (RAMPs). This approach is convenient for online modification of walk in unstructured and immediate environment of humans. The modification is specified just by changing the overall walking parameters (walking speed, direction, step length, ...) and the system automatically adapts walk realization (legs motion) to comply with new requirements. Modifications may be required anytime, even during motion realization. Simulation results illustrate proposed approach.

scholarly journals Effectiveness of an ankle–foot orthosis on walking in patients with stroke: a systematic review and meta-analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoo Jin Choo ◽  
Min Cheol Chang
Keyword(s):  
Stride Length ◽  
Walking Speed ◽  
Sagittal Plane ◽  
Meta Analysis ◽  
Step Length ◽  
Stride Time ◽  
Plane Angle ◽  
Ankle Foot Orthosis ◽  
Biomechanical Parameters ◽  
Foot Orthosis

AbstractWe conducted a meta-analysis to investigate the effectiveness of ankle–foot orthosis (AFO) use in improving gait biomechanical parameters such as walking speed, mobility, and kinematics in patients with stroke with gait disturbance. We searched the MEDLINE (Medical Literature Analysis and Retrieval System Online), CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase, and Scopus databases and retrieved studies published until June 2021. Experimental and prospective studies were included that evaluated biomechanics or kinematic parameters with or without AFO in patients with stroke. We analyzed gait biomechanical parameters, including walking speed, mobility, balance, and kinematic variables, in studies involving patients with and without AFO use. The criteria of the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate the methodological quality of the studies, and the level of evidence was evaluated using the Research Pyramid model. Funnel plot analysis and Egger’s test were performed to confirm publication bias. A total of 19 studies including 434 participants that reported on the immediate or short-term effectiveness of AFO use were included in the analysis. Significant improvements in walking speed (standardized mean difference [SMD], 0.50; 95% CI 0.34–0.66; P < 0.00001; I2, 0%), cadence (SMD, 0.42; 95% CI 0.22–0.62; P < 0.0001; I2, 0%), step length (SMD, 0.41; 95% CI 0.18–0.63; P = 0.0003; I2, 2%), stride length (SMD, 0.43; 95% CI 0.15–0.71; P = 0.003; I2, 7%), Timed up-and-go test (SMD, − 0.30; 95% CI − 0.54 to − 0.07; P = 0.01; I2, 0%), functional ambulation category (FAC) score (SMD, 1.61; 95% CI 1.19–2.02; P < 0.00001; I2, 0%), ankle sagittal plane angle at initial contact (SMD, 0.66; 95% CI 0.34–0.98; P < 0.0001; I2, 0%), and knee sagittal plane angle at toe-off (SMD, 0.39; 95% CI 0.04–0.73; P = 0.03; I2, 46%) were observed when the patients wore AFOs. Stride time, body sway, and hip sagittal plane angle at toe-off were not significantly improved (p = 0.74, p = 0.07, p = 0.07, respectively). Among these results, the FAC score showed the most significant improvement, and stride time showed the lowest improvement. AFO improves walking speed, cadence, step length, and stride length, particularly in patients with stroke. AFO is considered beneficial in enhancing gait stability and ambulatory ability.

Biped walking and stairs climbing using reconfigurable adaptive motion primitives

2016 ◽  
Author(s):  
Mirko Rakovic ◽  
Branislav Borovac ◽  
Jose Santos-Victor ◽  
Aleksandar Batinica ◽  
Milutin Nikolic ◽  
...  
Keyword(s):  
Biped Walking ◽  
Motion Primitives ◽  
Adaptive Motion

scholarly journals A Comparison of Treadmill and Overground Walking Effects on Step Cycle Asymmetry in Young and Older Individuals

2013 ◽  
Vol 29 (2) ◽  
pp. 188-193 ◽  
Author(s):  
Hanatsu Nagano ◽  
Rezaul K. Begg ◽  
William A. Sparrow ◽  
Simon Taylor
Keyword(s):  
Older Adults ◽  
Walking Speed ◽  
Step Length ◽  
Treadmill Walking ◽  
Older Individuals ◽  
Aging Effects ◽  
Overground Walking ◽  
Time Data ◽  
Step Cycle ◽  
Step Velocity

Although lower limb strength becomes asymmetrical with age, past studies of aging effects on gait biomechanics have usually analyzed only one limb. This experiment measured how aging and treadmill surface influenced both dominant and nondominant step parameters in older (mean 74.0 y) and young participants (mean 21.9 y). Step-cycle parameters were obtained from 3-dimensional position/time data during preferred-speed walking for 40 trials along a 10 m walkway and for 10 minutes of treadmill walking. Walking speed (young 1.23 m/s, older 1.24 m/s) and step velocity for the two age groups were similar in overground walking but older adults showed significantly slower walking speed (young 1.26 m/s, older 1.05 m/s) and step velocity on the treadmill due to reduced step length and prolonged step time. Older adults had shorter step length than young adults and both groups reduced step length on the treadmill. Step velocity and length of older adults’ dominant limb was asymmetrically larger. Older adults increased the proportion of double support in step time when treadmill walking. This adaptation combined with reduced step velocity and length may preserve balance. The results suggest that bilateral analyses should be employed to accurately describe asymmetric features of gait especially for older adults.

scholarly journals Models And Mining Of On-Line Social Networks

2021 ◽  
Author(s):  
Yanhua Tian
Keyword(s):  
Social Networks ◽  
Power Law ◽  
Degree Distribution ◽  
Small World ◽  
Spectral Expansion ◽  
On Line ◽  
Simulation Results ◽  
Small World Property ◽  
P Type ◽  
Law Degree

Power law degree distribution, the small world property, and bad spectral expansion are three of the most important properties of On-line Social Networks (OSNs). We sampled YouTube and Wikipedia to investigate OSNs. Our simulation and computational results support the conclusion that OSNs follow a power law degree distribution, have the small world property, and bad spectral expansion. We calculated the diameters and spectral gaps of OSNs samples, and compared these to graphs generated by the GEO-P model. Our simulation results support the Logarithmic Dimension Hypothesis, which conjectures that the dimension of OSNs is m = [log N]. We introduced six GEO-P type models. We ran simulations of these GEO-P-type models, and compared the simulated graphs with real OSN data. Our simulation results suggest that, except for the GEO-P (GnpDeg) model, all our models generate graphs with power law degree distributions, the small world property, and bad spectral expansion.

Design of Robust Approach for Failure Detection in Dynamic Control Systems

2013 ◽  
pp. 237-259
Author(s):  
Gomaa Zaki El-Far
Keyword(s):  
Nuclear Power ◽  
Dynamic Control ◽  
Control Process ◽  
Failure Detection ◽  
Global Optimum ◽  
Sampling Time ◽  
Nuclear Power Reactor ◽  
Control Actions ◽  
On Line ◽  
Simulation Results

This paper presents a robust instrument fault detection (IFD) scheme based on modified immune mechanism based evolutionary algorithm (MIMEA) that determines on line the optimal control actions, detects faults quickly in the control process, and reconfigures the controller structure. To ensure the capability of the proposed MIMEA, repeating cycles of crossover, mutation, and clonally selection are included through the sampling time. This increases the ability of the proposed algorithm to reach the global optimum performance and optimize the controller parameters through a few generations. A fault diagnosis logic system is created based on the proposed algorithm, nonlinear decision functions, and its derivatives with respect to time. Threshold limits are implied to improve the system dynamics and sensitivity of the IFD scheme to the faults. The proposed algorithm is able to reconfigure the control law safely in all the situations. The presented false alarm rates are also clearly indicated. To illustrate the performance of the proposed MIMEA, it is applied successfully to tune and optimize the controller parameters of the nonlinear nuclear power reactor such that a robust behavior is obtained. Simulation results show the effectiveness of the proposed IFD scheme based MIMEA in detecting and isolating the dynamic system faults.

Feedback Control of Planar Biped Robot With Regulable Step Length and Walking Speed

2011 ◽  
Vol 27 (1) ◽  
pp. 162-169 ◽  
Author(s):  
Yong Hu ◽  
Gangfeng Yan ◽  
Zhiyun Lin
Keyword(s):  
Feedback Control ◽  
Walking Speed ◽  
Biped Robot ◽  
Step Length

Comparison of Damped Velocity and Acceleration Control for Non-Redundant Manipulators

2000 ◽  
Author(s):  
Yu-Che Chen ◽  
Kevin A. O’Neil
Keyword(s):  
Path Tracking ◽  
Least Square ◽  
Dynamics Simulation ◽  
Control Algorithms ◽  
Redundant Manipulators ◽  
Velocity Control ◽  
Redundant Manipulator ◽  
Singular Configurations ◽  
On Line ◽  
Simulation Results

Abstract Damped Least Square (DLS) method has been widely used as an on-line algorithm for manipulator path tracking near and at singular configurations. Wampler (1986) formulated the framework of DLS method applied to velocity control and addressed the applicability of DLS method to acceleration control. The purpose of this paper is to demonstrate the differences in the joint paths generated by damped velocity and damped acceleration control algorithms in non-redundant manipulators. We examine these joint paths, find the cause of the differences, and demonstrate the features of damped acceleration control in non-redundant manipulator dynamics. Simulation results on a planar 2R and a spatial 6R manipulator moving through and near singular configurations verify the phenomena analyzed.

scholarly journals Regional effects of atmospheric aerosols on temperature: an evaluation of an ensemble of on-line coupled models

2017 ◽  
Author(s):  
Rocío Baró ◽  
Laura Palacios-Peña ◽  
Alexander Baklanov ◽  
Alessandra Balzarini ◽  
Dominik Brunner ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Forest Fires ◽  
Atmospheric Aerosol ◽  
Correlation Coefficients ◽  
Coupled Models ◽  
Climate Effect ◽  
On Line ◽  
Simulation Results ◽  
Radiative Feedbacks ◽  
Aerosol Radiative

Abstract. The climate effect of atmospheric aerosols is associated to their influence on the radiative budget of the Earth due to direct aerosol-radiation interactions (ARI) and indirect effects, resulting from aerosol-cloud interactions (ACI). On-line coupled meteorology-chemistry models permit the description of these effects on the basis of simulated atmospheric aerosol concentrations, although there is still some uncertainty associated to the use of these models. In this sense, the objective of this work is to assess whether the inclusion of atmospheric aerosol radiative feedbacks of an ensemble of on-line coupled models improves the simulation results for maximum, mean and minimum temperature over Europe. The evaluated model outputs originate from EuMetChem COST Action ES1004 simulations for Europe, differing in the inclusion (or omission) of ARI and ACI in the various models. The case studies cover two important atmospheric aerosol episodes over Europe in the year 2010, a heat wave and forest fires episode (July–August 2010) and a more humid episode including a Saharan desert dust outbreak in October 2010. The simulation results are evaluated against observational data from E-OBS gridded database. The results indicate that, although there is only a slight improvement in the bias of the simulation results when including the radiative feedbacks, the spatio-temporal variability and correlation coefficients are improved for the cases under study when atmospheric aerosol radiative effects are included, especially for those areas closest to emissions sources of atmospheric aerosols.

scholarly journals The Relationship between Walking Speed and Step Length in Older Aged Patients

Diseases ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 17 ◽  
Author(s):  
Yuji Morio ◽  
Kazuhiro Izawa ◽  
Yoshitsugu Omori ◽  
Hironobu Katata ◽  
Daisuke Ishiyama ◽  
...  
Keyword(s):  
Muscle Force ◽  
Walking Speed ◽  
Step Length ◽  
Knee Extension ◽  
Height Ratio ◽  
Roc Curve Analysis ◽  
Aged Patients ◽  
Speed Test ◽  
Slow Group ◽  
Fast Group

Compared with elderly people who have not experienced falls, those who have were reported to have a shortened step length, large fluctuations in their pace, and a slow walking speed. The purpose of this study was to elucidate the step length required to maintain a walking speed of 1.0 m/s in patients aged 75 years or older. We measured the 10 m maximum walking speed in patients aged 75 years or older and divided them into the following two groups: Those who could walk 1.0 m/s or faster (fast group) and those who could not (slow group). Step length was determined from the number of steps taken during the 10 m-maximum walking speed test, and the step length-to-height ratio was calculated. Isometric knee extension muscle force (kgf), modified functional reach (cm), and one-leg standing time (s) were also measured. We included 261 patients (average age: 82.1 years, 50.6% men) in this study. The fast group included 119 participants, and the slow group included 142 participants. In a regression logistic analysis, knee extension muscle force (p = 0.03) and step length-to-height ratio (p < 0.01) were determined as factors significantly related to the fast group. As a result of ROC curve analysis, a step length-to-height ratio of 31.0% could discriminate between the two walking speed groups. The results suggest that the step length-to-height ratio required to maintain a walking speed of 1.0 m/s is 31.0% in patients aged 75 years or older.

scholarly journals Framework for Developing Bio-Inspired Morphologies for Walking Robots

2020 ◽  
Vol 10 (19) ◽  
pp. 6986
Author(s):  
Peter Billeschou ◽  
Nienke N. Bijma ◽  
Leon B. Larsen ◽  
Stanislav N. Gorb ◽  
Jørgen C. Larsen ◽  
...  
Keyword(s):  
Walking Speed ◽  
Dung Beetle ◽  
Object Manipulation ◽  
Step Length ◽  
Legged Robots ◽  
Walking Robots ◽  
Beetle Species ◽  
Step Frequency ◽  
Development Framework ◽  
Interdisciplinary Collaborations

Morphology is a defining trait of any walking entity, animal or robot, and is crucial in obtaining movement versatility, dexterity and durability. Collaborations between biologist and engineers create opportunities for implementing bio-inspired morphologies in walking robots. However, there is little guidance for such interdisciplinary collaborations and what tools to use. We propose a development framework for transferring animal morphologies to robots and substantiate it with a replication of the ability of the dung beetle species Scarabaeus galenus to use the same morphology for both locomotion and object manipulation. As such, we demonstrate the advantages of a bio-inspired dung beetle-like robot, ALPHA, and how its morphology outperforms a conventional hexapod by increasing the (1) step length by 50.0%, (2) forward and upward reach by 95.5%, and by lowering the (3) overall motor acceleration by 7.9%, and (4) step frequency by 21.1% at the same walking speed. Thereby, the bio-inspired robot has longer and fewer steps that lower fatigue-inducing impulses, a greater variety of step patterns, and can potentially better utilise its workspace to overcome obstacles. Hence, we demonstrate how the framework can be used to develop legged robots with bio-inspired morphologies that embody greater movement versatility, dexterity and durability.

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