Stability Control of a Three-Dimensional Passive Walker by Periodic Input Based on the Frequency Entrainment

2011 ◽  
Vol 23 (6) ◽  
pp. 1100-1107 ◽  
Author(s):  
Soichiro Suzuki ◽  
◽  
Masamichi Takada ◽  
Yuta Iwakura ◽  
Keyword(s):  
Initial Conditions ◽  
Three Dimensional ◽  
Stability Control ◽  
Human Gait ◽  
Mechanical Oscillator ◽  
Frequency Entrainment ◽  
Passive Walking ◽  
Periodic Input ◽  
The Stability ◽  
Human Gait Analysis

This study proposes a new control that stabilizes a three-dimensional (3D) passive walker without torque input at knees and ankles joints by using entrainment and a mechanical oscillator. It is difficult to stabilize a 3D biped passive walker in different environments because the range of initial conditions for stable walking is limited, so we designed a 3D biped passive walker as a passive walking platform by considering the results of human gait analysis to make the success of passive walking high. The stability of this platform was analytically determined by analyzing the frontal movement limit cycle. In the new control, the frontalmovement period is synchronized with the swing-leg period by a mechanical oscillator on the top of the walker. The mechanical oscillator controller generates a target path to synchronize oscillatormovement with swing-leg movement using frequency entrainment. The walker is stabilized when the frontal movement period was synchronized with the swing-leg period by periodic input generated by the mechanical oscillator. It was experimentally found consequently that the walker was stabilized on different slopes and flat floors.

scholarly journals Climbing and Turning Control of a Biped Passive Walker by Periodic Input Based on Frequency Entrainment

2011 ◽  
Vol 2-3 ◽  
pp. 48-52 ◽  
Author(s):  
Soichiro Suzuki ◽  
Ying Cao ◽  
Masamichi Takada ◽  
Kentaro Oi
Keyword(s):  
Control Method ◽  
Three Dimensional ◽  
Frontal Plane ◽  
The Novel ◽  
Mechanical Oscillator ◽  
Frequency Entrainment ◽  
Periodic Input ◽  
Target Path ◽  
Turning Control

This study is aimed at stabilizing a three dimensional biped passive walker in various environments and achieving climbing and turning control. The novel control method synchronizes a period of the changing motion of the stance leg in frontal plane (frontal motion) with a period of the swing leg by periodic input in order to stabilize the three dimensional passive walker. A mechanical oscillator is utilized to change the period of the frontal motion. The target path of the oscillator is automatically generated based on frequency entrainment in order to adjust the period of the frontal motion. In the climbing and turning control of the passive walker, the amplitude and the phase generating algorithm of the target path of the oscillator are improved. It is analytically demonstrated that the biped passive walker can be stabilized even in climbing and turning.

scholarly journals A Fractional-Order Discrete Noninvertible Map of Cubic Type: Dynamics, Control, and Synchronization

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Xiaojun Liu ◽  
Ling Hong ◽  
Lixin Yang ◽  
Dafeng Tang
Keyword(s):  
Fractional Order ◽  
Initial Conditions ◽  
Dimensional Space ◽  
Equilibrium Points ◽  
Three Dimensional ◽  
State Variables ◽  
Discrete Maps ◽  
The Stability ◽  
Control And Synchronization ◽  
Simultaneous Variation

In this paper, a new fractional-order discrete noninvertible map of cubic type is presented. Firstly, the stability of the equilibrium points for the map is examined. Secondly, the dynamics of the map with two different initial conditions is studied by numerical simulation when a parameter or a derivative order is varied. A series of attractors are displayed in various forms of periodic and chaotic ones. Furthermore, bifurcations with the simultaneous variation of both a parameter and the order are also analyzed in the three-dimensional space. Interior crises are found in the map as a parameter or an order varies. Thirdly, based on the stability theory of fractional-order discrete maps, a stabilization controller is proposed to control the chaos of the map and the asymptotic convergence of the state variables is determined. Finally, the synchronization between the proposed map and a fractional-order discrete Loren map is investigated. Numerical simulations are used to verify the effectiveness of the designed synchronization controllers.

Novel Periodic and Turning Motions in the Simplest Passive Walking Model

2014 ◽  
Author(s):  
M. R. Sabaapour ◽  
M. R. Hairi Yazdi ◽  
B. Beigzadeh
Keyword(s):  
Periodic Motion ◽  
Essential Feature ◽  
Basin Of Attraction ◽  
Three Dimensional ◽  
Surface Profile ◽  
Passive Walking ◽  
The Stability ◽  
Special Case ◽  
Stable Passive ◽  
Passive Turning

The ability to move along curved paths is an essential feature for biped walkers to move around obstacles. This study is aimed at extending passive walking concept for curved walking and turning to generate more natural and effective motion. Hence three-dimensional (3D) motion of a rimless spoked-wheel, as the simplest walking model, about a general vertical fixed coordinate system has been derived. Then, two kinds of a stable passive turning, i.e. limited and circular continuous have been considered and discussed. The first kind is actually transferring from a 2D periodic motion to another, and can be implemented on a straight slope surface. While, it was shown that the second kind is just related to novel 3D periodic motions and can be recognized on a special surface profile namely “helical slope” introduced here. The latter are interpreted as 3D fixed points of a Poincare return map again. So, their stability was evaluated numerically by a Jacobian analysis and demonstrated through several simulations. Results show asymptotical stability of such motions and their considerable basin of attraction with respect to initial states. In addition, the characteristic of passive turning is shown to be strictly connected with the value of the initial perturbed condition, for instance, to the initial inclination of the wheel. It is then surprising to note that the stability of a 3D passive periodic motion (turning) is higher than 2D one (straight walking) which is actually a special case just with an infinite radius of turn.

Stability Control and Simulation of Wheel-Legged Mobile Robot in Mechanical Engineering

2013 ◽  
Vol 644 ◽  
pp. 123-128
Author(s):  
Ling Yu Sun ◽  
Jian Hua Zhang ◽  
Xiao Jun Zhang
Keyword(s):  
Mobile Robot ◽  
Pid Control ◽  
Control Method ◽  
Three Dimensional ◽  
Stability Domain ◽  
Stability Control ◽  
Terrestrial Environment ◽  
The Stability ◽  
Adaptive Pid Control ◽  
Fuzzy Adaptive

The wheel-legged mobile robot in a complex three-dimensional environment has strong through capacity .Study is very critical for the stability of the control of their body systems. In this paper , based on analysis of the structure of wheel-legged mobile robot designed, the stability is evaluated by the use of (Effective Mass Center) EMC , and the stability domain is established accordingly. A fuzzy adaptive PID control method is created , and verified by ADAMS and MATLAB co-simulation . Simulation results show that the robot in different terrestrial environment, can maintain good stability.

scholarly journals Two-dimensional video-based analysis of human gait using pose estimation

2020 ◽  
Author(s):  
Jan Stenum ◽  
Cristina Rossi ◽  
Ryan T. Roemmich
Keyword(s):  
Gait Analysis ◽  
Motion Capture ◽  
Pose Estimation ◽  
Gold Standard ◽  
Three Dimensional ◽  
Human Gait ◽  
Large Set ◽  
Two Dimensional ◽  
Gait Parameters ◽  
Human Gait Analysis

ABSTRACTWalking is the primary mode of human locomotion. Accordingly, people have been interested in studying human gait since at least the fourth century BC. Human gait analysis is now common in many fields of clinical and basic research, but gold standard approaches – e.g., three-dimensional motion capture, instrumented mats or footwear, and wearables – are often expensive, immobile, data-limited, and/or require specialized equipment or expertise for operation. Recent advances in video-based pose estimation have suggested exciting potential for analyzing human gait using only two-dimensional video inputs collected from readily accessible devices (e.g., smartphones, tablets). However, we currently lack: 1) data about the accuracy of video-based pose estimation approaches for human gait analysis relative to gold standard measurement techniques and 2) an available workflow for performing human gait analysis via video-based pose estimation. In this study, we compared a large set of spatiotemporal and sagittal kinematic gait parameters as measured by OpenPose (a freely available algorithm for video-based human pose estimation) and three-dimensional motion capture from trials where healthy adults walked overground. We found that OpenPose performed well in estimating many gait parameters (e.g., step time, step length, sagittal hip and knee angles) while some (e.g., double support time, sagittal ankle angles) were less accurate. We observed that mean values for individual participants – as are often of primary interest in clinical settings – were more accurate than individual step-by-step measurements. We also provide a workflow for users to perform their own gait analyses and offer suggestions and considerations for future approaches.

scholarly journals Two-dimensional video-based analysis of human gait using pose estimation

2021 ◽  
Vol 17 (4) ◽  
pp. e1008935
Author(s):  
Jan Stenum ◽  
Cristina Rossi ◽  
Ryan T. Roemmich
Keyword(s):  
Gait Analysis ◽  
Motion Capture ◽  
Pose Estimation ◽  
Mean Absolute Error ◽  
Three Dimensional ◽  
Absolute Error ◽  
Human Gait ◽  
Two Dimensional ◽  
Gait Parameters ◽  
Human Gait Analysis

Human gait analysis is often conducted in clinical and basic research, but many common approaches (e.g., three-dimensional motion capture, wearables) are expensive, immobile, data-limited, and require expertise. Recent advances in video-based pose estimation suggest potential for gait analysis using two-dimensional video collected from readily accessible devices (e.g., smartphones). To date, several studies have extracted features of human gait using markerless pose estimation. However, we currently lack evaluation of video-based approaches using a dataset of human gait for a wide range of gait parameters on a stride-by-stride basis and a workflow for performing gait analysis from video. Here, we compared spatiotemporal and sagittal kinematic gait parameters measured with OpenPose (open-source video-based human pose estimation) against simultaneously recorded three-dimensional motion capture from overground walking of healthy adults. When assessing all individual steps in the walking bouts, we observed mean absolute errors between motion capture and OpenPose of 0.02 s for temporal gait parameters (i.e., step time, stance time, swing time and double support time) and 0.049 m for step lengths. Accuracy improved when spatiotemporal gait parameters were calculated as individual participant mean values: mean absolute error was 0.01 s for temporal gait parameters and 0.018 m for step lengths. The greatest difference in gait speed between motion capture and OpenPose was less than 0.10 m s−1. Mean absolute error of sagittal plane hip, knee and ankle angles between motion capture and OpenPose were 4.0°, 5.6° and 7.4°. Our analysis workflow is freely available, involves minimal user input, and does not require prior gait analysis expertise. Finally, we offer suggestions and considerations for future applications of pose estimation for human gait analysis.

scholarly journals Stability Control of a Biped Passive Walker by Periodic Input Based on the Frequency Entrainment(Mechanical Systems)

2010 ◽  
Vol 76 (771) ◽  
pp. 3058-3065
Author(s):  
Soichiro SUZUKI ◽  
Masayasu HACHIYA ◽  
Kenji SHIMIZU ◽  
Yuta IWAKURA ◽  
Masamichi TAKADA
Keyword(s):  
Mechanical Systems ◽  
Stability Control ◽  
Frequency Entrainment ◽  
Periodic Input

Three-Dimensional Coordinate Data Processing in Human Motion Analysis

1979 ◽  
Vol 101 (4) ◽  
pp. 279-283 ◽  
Author(s):  
T. P. Andriacchi ◽  
S. J. Hampton ◽  
A. B. Schultz ◽  
J. O. Galante
Keyword(s):  
Data Processing ◽  
Gait Analysis ◽  
Three Dimensional ◽  
Human Motion ◽  
Human Gait ◽  
Human Motion Analysis ◽  
Coordinate Processing ◽  
Three Dimensional Coordinate ◽  
Human Gait Analysis ◽  
Coordinate Data

A method for three-dimensional coordinate processing of human motion is presented. The method is well suited for use with opto-electronic data acquisition equipment. A resolution of one part in 500 was achieved over a viewing field of 2.4 m. This resolution was found to be adequate for human gait analysis studies.

Experiments on the stability of convection rolls in fluids whose viscosity depends on temperature

1978 ◽  
Vol 89 (3) ◽  
pp. 553-560 ◽  
Author(s):  
Frank M. Richter
Keyword(s):  
Rayleigh Number ◽  
Thermal Boundary Layer ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Hexagonal Cell ◽  
Low Viscosity ◽  
Viscosity Increase ◽  
The Stability ◽  
Convection Rolls ◽  
Rayleigh Numbers

The stability of two-dimensional convection rolls has been studied as a function of the Rayleigh number, wavenumber and variation in viscosity. The experiments used controlled initial conditions for the wavenumber, Rayleigh numbers up to 25 000 and variations in viscosity up to a factor of about 20. The parameter range of stable rolls is bounded by a hexagonal-cell regime at small Rayleigh numbers and large variations in viscosity. Otherwise, the rolls are subject to the same transitions as have already been studied in fluids of uniform viscosity. The bimodal instability leading to a stable three-dimensional pattern occurs at smaller values of the average Rayleigh number as the variations in viscosity increase. This appears to be a consequence of the low viscosity of the warm thermal boundary layer associated with the original rolls.

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