scholarly journals Identification of COM Controller of a Human in Stance Based on Motion Measurement and Phase-Space Analysis

2022 ◽  
Vol 8 ◽  
Author(s):  
Tomomichi Sugihara ◽  
Daishi Kaneta ◽  
Nobuyuki Murai
Keyword(s):  
Piecewise Linear ◽  
Center Of Mass ◽  
Feedback System ◽  
Humanoid Robots ◽  
The State ◽  
Whole Body ◽  
Linear Feedback ◽  
Motion Measurement ◽  
Motion Trajectories ◽  
Measurement Protocol

This article proposes a process to identify the standing stabilizer, namely, the controller in humans to keep upright posture stable against perturbations. We model the controller as a piecewise-linear feedback system, where the state of the center of mass (COM) is regulated by coordinating the whole body so as to locate the zero-moment point (ZMP) at the desired position. This was developed for humanoid robots and is possibly able to elaborate the fundamental control scheme used by humans to stabilize themselves. Difficulties lie on how to collect motion trajectories in a wide area of the state space for reliable identification and how to identify the piecewise-affine dynamical system. For the former problem, a motion measurement protocol is devised based on the theoretical phase portrait of the system. Regarding the latter problem, some clustering techniques including K-means method and EM (Expectation-and-Maximization) algorithm were examined. We found that a modified K-means method produced the most accurate result in this study. The method was applied to the identification of a lateral standing controller of a human subject. The result of the identification quantitatively supported a hypothesis that the COM-ZMP regulator reasonably models the human’s controller when deviations of the angular momentum about the COM are limited.

Experimental Evidence for Chaotic Response in a Feedback System

1991 ◽  
Vol 113 (1) ◽  
pp. 183-187 ◽  
Author(s):  
M. F. Golnaraghi ◽  
F. C. Moon
Keyword(s):  
Piecewise Linear ◽  
Feedback System ◽  
Piecewise Linear Function ◽  
Linear Feedback ◽  
Order System ◽  
Feedback Gain ◽  
Chaotic Motions ◽  
Control Gain ◽  
Positioning Device ◽  
Dimensional Equation

In this paper, the dynamics of a one-degree-of-freedom mechanical positioning device with nonlinear stiffness and linear feedback are described. Experimental results show that chaotic dynamics can result due to an increase in control gain or shuttle frequency. Adding sufficient damping through velocity feedback gain, however, eliminated the chaos. In some chaotic motions, a one-dimensional delay map was obtained from the experimental time samples. The map was modeled by a piecewise linear function, which suggested that the third-order system might be modeled by a lower dimensional equation.

Modeling of Human Posturokinetic Movements by a Linear Feedback System: Relations among Feedback Coefficients

2002 ◽  
Vol 95 (1) ◽  
pp. 308-318 ◽  
Author(s):  
Karen Roux ◽  
Christian Gentil ◽  
Alexander Grishin
Keyword(s):  
Neural Control ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Movement Analysis ◽  
Feedback System ◽  
Whole Body ◽  
Linear Feedback ◽  
State Variables ◽  
Joint Torques ◽  
Angular Velocities

This study describes a method of modeling human trunk and whole body backward bending and suggests a possible neural control strategy. The hypothesis was that the control system can be modeled as a linear feedback system, in which the torque acting at a given joint is a function of the state variables (angular positions and angular velocities). The linear system enabled representation of the feedback system by a gain matrix. The matrix was computed from the kinematics recorded by a movement analysis system and from the joint torques calculated by inverse dynamics. To validate the control model, a comparison was made between the angular kinematics yielded by the model and the experimental data. Moreover, for all subjects, the same relationships between feedback coefficients were found although gain values were different. The study showed that the feedback system is an appropriate model of the strategy from performing an accurate controlled trunk or whole body backward bending in the sagittal plane.

Continuous Estimation of CO2 Production during Exercise

1997 ◽  
Vol 36 (04/05) ◽  
pp. 368-371
Author(s):  
R. Soma ◽  
Y. Yamamoto
Keyword(s):  
Fuzzy Logic ◽  
Steady State ◽  
Infusion Rate ◽  
Feedback System ◽  
Whole Body ◽  
Co2 Production ◽  
Cycle Exercise ◽  
Continuous Estimation ◽  
Breath Measurement ◽  
13Co2 Enrichment

Abstract.A new method was developed for continuous isotopic estimation of human whole body CO2 rate of appearance (Ra) during non-steady state exercise. The technique consisted of a breath-by-breath measurement of 13CO2 enrichment (E) and a real-time fuzzy logic feedback system which controlled NaH13CO3 infusion rate to achieve an isotopic steady state. Ra was estimated from the isotope infusion rate and body 13CO2 enrichment which was equal to E at the isotopic steady state. During a non-steady state incremental cycle exercise (5 w/min or 10 w/min), NaH13CO3 infusion rate was successfully increased by the action of feedback controller so as to keep E constant.

Propaganda as a means of implementing the ideological function of the state

2020 ◽  
Vol 2020 (3) ◽  
pp. 10-14
Author(s):  
Aleksey Bredikhin ◽  
Andrei Udaltsov
Keyword(s):  
Mass Media ◽  
Feedback System ◽  
Legal Framework ◽  
The State ◽  
The Political ◽  
Special Position ◽  
Equal Footing ◽  
Constitutional Order ◽  
Political Situation ◽  
The Mass Media

In the article the authors analyze the essence of propaganda as a means of implementing ideological function of the state. It is noted that propaganda is a mechanism of spreading information persuasive influence in the interpretation and estimation of state power representatives. The structure of propaganda is determined: beneficiary of propaganda, subjects of propaganda, content of propaganda, channels of realization of propaganda, addressee of propaganda, feedback system. Types of propaganda are distinguished: political, axiological, educational, preventive. The authors come to the conclusion that the basic directions and the propaganda content are established in normative acts and the programs and organizational actions accepted according to them. Along with the implementation of propaganda, the ideological function is implemented by prohibiting or restricting propaganda or other dissemination of information that endangers the foundations of the constitutional order and is otherwise aimed at destabilizing the political situation in the State, as well as prohibiting the propaganda of ideas that may harm the foundations of morality and morality. The mass media are essential in carrying out propaganda. The State widely uses this resource on an equal footing with other actors to disseminate ideas of public importance and uses the services of various communication agencies. However, the state forms a legal framework for the mass media, their rights and limitations, which still determines the special position of the state in this process.

scholarly journals Correlation of age, sex and season with the state of human decomposition as quantified by postmortem computed tomography

2021 ◽  
Author(s):  
Dominic L. C. Guebelin ◽  
Akos Dobay ◽  
Lars Ebert ◽  
Eva Betschart ◽  
Michael J. Thali ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Demographic Data ◽  
Sociodemographic Factors ◽  
The State ◽  
The Body ◽  
Seasonal Effects ◽  
Whole Body ◽  
Postmortem Computed Tomography ◽  
Whole Body Computed Tomography ◽  
Urban Study

AbstractDead bodies exhibit a variable range of changes with advancing decomposition. To quantify intracorporeal gas, the radiological alteration index (RAI) has been implemented in the assessment of postmortem whole-body computed tomography. We used this RAI as a proxy for the state of decomposition. This study aimed to (I) investigate the correlation between the state of decomposition and the season in which the body was discovered; and (II) evaluate the correlations between sociodemographic factors (age, sex) and the state of decomposition, by using the RAI as a proxy for the extent of decomposition. In a retrospective study, we analyzed demographic data from all autopsy reports from the Institute of Forensic Medicine of Zurich between January 2017 to July 2019 and evaluated the radiological alteration index from postmortem whole-body computed tomography for each case. The bodies of older males showed the highest RAI. Seasonal effects had no significant influence on the RAI in our urban study population with bodies mostly being discovered indoors. Autopsy reports contain valuable data that allow interpretation for reasons beyond forensic purposes, such as sociopolitical observations.

A Computationally Efficient Predictive Controller for Lane Keeping of Semi-Autonomous Vehicles

2014 ◽  
Author(s):  
Changchun Liu ◽  
Chankyu Lee ◽  
Andreas Hansen ◽  
J. Karl Hedrick ◽  
Jieyun Ding
Keyword(s):  
Autonomous Vehicles ◽  
Piecewise Linear ◽  
Computational Cost ◽  
Parametric Programming ◽  
Linear Feedback ◽  
Loop Model ◽  
Computationally Efficient ◽  
Feedback Function ◽  
Predictive Controller ◽  
Lane Keeping

Model predictive control (MPC) is a popular technique for the development of active safety systems. However, its high computational cost prevents it from being implemented on lower-cost hardware. This paper presents a computationally efficient predictive controller for lane keeping assistance systems. The controller shares control with the driver, and applies a correction steering when there is a potential lane departure. Using the explicit feedback MPC, a multi-parametric nonlinear programming problem with a human-in-the-loop model and safety constraints is formulated. The cost function is chosen as the difference between the linear state feedback function to be determined and the resultant optimal control sequence of the MPC problem solved off-line given the current state. The piecewise linear feedback function is obtained by solving the parametric programming with an approximation approach. The effectiveness of the controller is evaluated through numerical simulations.

scholarly journals Turning Gait Planning Method for Humanoid Robots

2018 ◽  
Vol 8 (8) ◽  
pp. 1257 ◽  
Author(s):  
Tianqi Yang ◽  
Weimin Zhang ◽  
Xuechao Chen ◽  
Zhangguo Yu ◽  
Libo Meng ◽  
...  
Keyword(s):  
Inverted Pendulum ◽  
Center Of Mass ◽  
Translational Motion ◽  
Humanoid Robots ◽  
Inverted Pendulum Model ◽  
Straight Line ◽  
Pendulum Model ◽  
The Stability ◽  
And Control ◽  
Present Simulation

The most important feature of this paper is to transform the complex motion of robot turning into a simple translational motion, thus simplifying the dynamic model. Compared with the method that generates a center of mass (COM) trajectory directly by the inverted pendulum model, this method is more precise. The non-inertial reference is introduced in the turning walk. This method can translate the turning walk into a straight-line walk when the inertial forces act on the robot. The dynamics of the robot model, called linear inverted pendulum (LIP), are changed and improved dynamics are derived to make them apply to the turning walk model. Then, we expend the new LIP model and control the zero moment point (ZMP) to guarantee the stability of the unstable parts of this model in order to generate a stable COM trajectory. We present simulation results for the improved LIP dynamics and verify the stability of the robot turning.

Impact of Age and Body Mass Index on Anthropometry in Working Adults

2017 ◽  
Vol 61 (1) ◽  
pp. 1341-1345 ◽  
Author(s):  
Zachary Merrill ◽  
April Chambers ◽  
Rakié Cham
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Center Of Mass ◽  
Biomechanical Model ◽  
Whole Body ◽  
Working Adults ◽  
Biomechanical Models ◽  
Scan Data ◽  
Body Segment Parameters ◽  
The Impact

Body segment parameters (BSPs) such as segment mass and center of mass are used as inputs in ergonomic design and biomechanical models to predict the risk of musculoskeletal injuries. These models have been shown to be sensitive to the BSP values used as inputs, demonstrating the necessity of using accurate and representative parameters. This study aims to provide accurate BSPs by quantifying the impact of age and body mass index on torso and thigh mass and center of mass in working adults using whole body dual energy x-ray absorptiometry (DXA) scan data. The results showed significant effects of gender, age, and body mass index (BMI) on torso and thigh mass and center of mass, as well as significant effects of age and BMI within genders, indicating that age, gender, and BMI need to be taken into account when predicting BSPs in order to calculate representative ergonomic and biomechanical model outputs.

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