Strategies for the Control of Balance During Locomotion

2018 ◽  
Vol 7 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Hendrik Reimann ◽  
Tyler Fettrow ◽  
John J. Jeka
Keyword(s):  
Degrees Of Freedom ◽  
Neural Control ◽  
Control Strategies ◽  
Mechanical Effect ◽  
Space Representation ◽  
Control Mechanisms ◽  
Step Width ◽  
Foot Placement ◽  
The Central Nervous System ◽  
Phase Space Representation

The neural control of balance during locomotion is currently not well understood, even in the light of considerable advances in research on balance during standing. In this paper, we lay out the control problem for this task and present a list of different strategies available to the central nervous system to solve this problem. We discuss the biomechanics of the walking body, using a simplified model that iteratively gains degrees of freedom and complexity. Each addition allows for different control strategies, which we introduce in turn: foot placement shift, ankle strategy, hip strategy, and push-off modulation. The dynamics of the biomechanical system are discussed using the phase space representation, which allows illustrating the mechanical effect of the different control mechanisms. This also enables us to demonstrate the effects of common general stability strategies, such as increasing step width and cadence.

Multivariable Control of an Over-Head Crane System Based on Entire Eigen-Structure Assignment

2010 ◽  
Author(s):  
Hamed Moradi ◽  
K. Haji Hajikolaei ◽  
Firooz Bakhtiari-Nejad ◽  
Aria Alasty
Keyword(s):  
Degrees Of Freedom ◽  
Linear Time ◽  
Control Strategies ◽  
Control Signal ◽  
Space Representation ◽  
Linear Time Invariant ◽  
State Space Representation ◽  
Stabilization Control ◽  
Structure Assignment ◽  
Time Invariant

Motion and stabilization control strategies are required to improve positioning accuracy, transportation time and swing angle of an overhead crane system. In this paper, a controller is designed to enhance both efficiency and safety and to extend the system application to other engineering fields. An over-head crane is modeled as a linear time invariant (LTI) system with two degrees of freedom. Trolley position and cable angle are the controlled outputs while the force exerted on trolley and torque on the load are the control inputs of the system. After state-space representation of the problem, feedback control is designed for tracking objective. An increase in the overall speed of the system time response corresponds to an increase in the control signal and leads to additional cost. Therefore, developing a code in MATLAB, eigenvalues and eigenvectors of the system are chosen optimally until an appropriate response is achieved; while the gains of control signal remain small.

Hand function: peripheral and central constraints on performance

2004 ◽  
Vol 96 (6) ◽  
pp. 2293-2300 ◽  
Author(s):  
Marc H. Schieber ◽  
Marco Santello
Keyword(s):  
Degrees Of Freedom ◽  
Neural Control ◽  
Control Strategies ◽  
Hand Function ◽  
Finger Movements ◽  
Neural Architecture ◽  
Neuromuscular Apparatus ◽  
Experimental Approaches ◽  
Coordination Patterns ◽  
Biological Motor

The hand is one of the most fascinating and sophisticated biological motor systems. The complex biomechanical and neural architecture of the hand poses challenging questions for understanding the control strategies that underlie the coordination of finger movements and forces required for a wide variety of behavioral tasks, ranging from multidigit grasping to the individuated movements of single digits. Hence, a number of experimental approaches, from studies of finger movement kinematics to the recording of electromyographic and cortical activities, have been used to extend our knowledge of neural control of the hand. Experimental evidence indicates that the simultaneous motion and force of the fingers are characterized by coordination patterns that reduce the number of independent degrees of freedom to be controlled. Peripheral and central constraints in the neuromuscular apparatus have been identified that may in part underlie these coordination patterns, simplifying the control of multi-digit grasping while placing certain limitations on individuation of finger movements. We review this evidence, with a particular emphasis on how these constraints extend through the neuromuscular system from the behavioral aspects of finger movements and forces to the control of the hand from the motor cortex.

scholarly journals On the complex nature of speech kinematics

2005 ◽  
Vol 42 ◽  
pp. 137-165
Author(s):  
Susanne Fuchs ◽  
Pascal Perrier
Keyword(s):  
Motor Control ◽  
Physical Properties ◽  
Vocal Tract ◽  
Control Strategies ◽  
Complex Nature ◽  
Control Mechanisms ◽  
Articulatory Movements ◽  
Control Research ◽  
The Central Nervous System ◽  
Speech Kinematics

Studying kinematic behavior in speech production is an indispensable and fruitful methodology in order to describe for instance phonemic contrasts, allophonic variations, prosodic effects in articulatory movements. More intriguingly, it is also interpreted with respect to its underlying control mechanisms. Several interpretations have been borrowed from motor control studies of arm, eye, and limb movements. They do either explain kinematics with respect to a fine tuned control by the Central Nervous System (CNS) or they take into account a combination of influences arising from motor control strategies at the CNS level and from the complex physical properties of the peripheral speech apparatus. We assume that the latter is more realistic and ecological. The aims of this article are: first, to show, via a literature review related to the so called '1/3 power law' in human arm motor control, that this debate is of first importance in human motor control research in general. Second, to study a number of speech specific examples offering a fruitful framework to address this issue. However, it is also suggested that speech motor control differs from general motor control principles in the sense that it uses specific physical properties such as vocal tract limitations, aerodynamics and biomechanics in order to produce the relevant sounds. Third, experimental and modelling results are described supporting the idea that the three properties are crucial in shaping speech kinematics for selected speech phenomena. Hence, caution should be taken when interpreting kinematic results based on experimental data alone.  

Freezing Degrees of Freedom During Motor Learning: A Systematic Review

Motor Control ◽  
2020 ◽  
Vol 24 (3) ◽  
pp. 457-471 ◽  
Author(s):  
Anderson Nascimento Guimarães ◽  
Herbert Ugrinowitsch ◽  
Juliana Bayeux Dascal ◽  
Alessandra Beggiato Porto ◽  
Victor Hugo Alves Okazaki
Keyword(s):  
Motor Learning ◽  
Control Strategy ◽  
Degrees Of Freedom ◽  
Control Strategies ◽  
System Solution ◽  
Dart Throwing ◽  
The Central Nervous System ◽  
Enormous Variation ◽  
And Control ◽  
Selection Of

According to Bernstein, the central nervous system solution to the human body’s enormous variation in movement choice and control when directing movement—the problem of degrees of freedom (DF)—is to freeze the number of possibilities at the beginning of motor learning. However, different strategies of freezing DF are observed in literature, and the means of selection of the control strategy during learning is not totally clear. This review investigated the possible effects of the class and objectives of the skill practiced on DF control strategies. The results of this review suggest that freezing or releasing the DF at the beginning of learning does not depend on the class (e.g., discrete skill class: football kick, dart throwing; continuous skill class: athletic march, handwriting) or objective of the skill (e.g., balance, velocity, and accuracy), in isolation. However, an interaction between these two skill elements seems to exist and influences the selection of the DF control strategy.

scholarly journals Spatial orientation and the representation of space with parietal lobe lesions

1997 ◽  
Vol 352 (1360) ◽  
pp. 1411-1419 ◽  
Author(s):  
Hans–Otto Karnath
Keyword(s):  
Parietal Cortex ◽  
Neural Control ◽  
Parietal Lobe ◽  
Peripersonal Space ◽  
Spatial Neglect ◽  
Neural Representation ◽  
Space Representation ◽  
Control Mechanisms ◽  
Optic Ataxia ◽  
Representation Of Space

Damage to the human parietal cortex leads to disturbances of spatial perception and of motor behaviour. Within the parietal lobe, lesions of the superior and of the inferior lobule induce quite different, characteristic deficits. Patients with inferior (predominantly right) parietal–lobe lesions fail to explore the contralesional part of space by eye or limb movements (spatial neglect). In contrast, superior parietal lobe lesions lead to specific impairments of goal–directed movements (optic ataxia). The observations reported in this paper support the view of dissociated functions represented in the inferior and the superior lobule of the human parietal cortex. They suggest that a spatial reference frame for exploratory behaviour is disturbed in patients with neglect. Data from these patients’ visual search argue that their failure to explore the contralesional side is due to a disturbed input transformation leading to a deviation of egocentric space representation to the ipsilesional side. Data further show that this deviation follows a rotation around the earth–vertical body axis to the ipsilesional side rather than a translation towards that side. The results are in clear contrast to explanations that assume a lateral gradient ranging from a minimum of exploration in the extreme contralesional to a maximum in the extreme ipsilesional hemispace. Moreover, the failure to orient towards and to explore the contralesional part of space appears to be distinct from those deficits observed once an object of interest has been located and releases reaching. Although patients with neglect exhibit a severe bias of exploratory movements, their hand trajectories to targets in peripersonal space may follow a straight path. This result suggests that (i) exploratory and (ii) goal–directed behaviour in space do not share the same neural control mechanisms. Neural representation of space in the inferior parietal lobule seems to serve as a matrix for spatial exploration and for orienting in space but not for visuomotor processes involved in reaching for objects. Disturbances of such processes rather appear to be prominent in patients with more superior parietal lobe lesions and optic ataxia.

Phase space representation of pseudo oscillator

1969 ◽  
Vol 29 (5) ◽  
pp. 245-246 ◽  
Author(s):  
A.K. Jaiswal ◽  
C.L. Mehta
Keyword(s):  
Phase Space ◽  
Space Representation ◽  
Phase Space Representation

Automated classification of human lung sound signals using phase space representation of intrinsic mode function

2021 ◽  
Author(s):  
Sibghatullah I. Khan ◽  
Vikram Palodiya ◽  
Lavanya Poluboyina
Keyword(s):  
Phase Space ◽  
Human Lung ◽  
Feature Space ◽  
Normal Lung ◽  
Space Representation ◽  
Support Vector ◽  
Lung Sounds ◽  
Lung Sound ◽  
Phase Space Representation

Abstract Bronchiectasis and chronic obstructive pulmonary disease (COPD) are common human lung diseases. In general, the expert pulmonologistcarries preliminary screening and detection of these lung abnormalities by listening to the adventitious lung sounds. The present paper is an attempt towards the automatic detection of adventitious lung sounds ofBronchiectasis,COPD from normal lung sounds of healthy subjects. For classification of the lung sounds into a normaland adventitious category, we obtain features from phase space representation (PSR). At first, the empirical mode decomposition (EMD) is applied to lung sound signals to obtain intrinsic mode functions (IMFs). The IMFs are then further processed to construct two dimensional (2D) and three dimensional (3D) PSR. The feature space includes the 95% confidence ellipse area and interquartile range (IQR) of Euclidian distances computed from 2D and 3D PSRs, respectively. The process is carried out for the first four IMFs correspondings to normal and adventitious lung sound signals. The computed features depicta significant ability to discriminate the two categories of lung sound signals.To perform classification, we use the least square support vector machine with two kernels, namely, polynomial and radial basis function (RBF).Simulation outcomes on ICBHI 2017 lung sound dataset show the ability of the proposed method in effectively classifying normal and adventitious lung sound signals. LS-SVM is employing RBF kernel provides the highest classification accuracy of 97.67 % over feature space constituted by first, second, and fourth IMF.

scholarly journals Control Strategies for Gait Tele-Rehabilitation System Based on Parallel Robotics

2021 ◽  
Vol 11 (23) ◽  
pp. 11095
Author(s):  
Antonio P. L. Bo ◽  
Leslie Casas ◽  
Gonzalo Cucho-Padin ◽  
Mitsuhiro Hayashibe ◽  
Dante Elias
Keyword(s):  
Degrees Of Freedom ◽  
Control Strategies ◽  
Subjective Evaluation ◽  
Wearable Sensors ◽  
Movement Data ◽  
Trunk Inclination ◽  
Limited Degree ◽  
Parallel Robotics ◽  
Limb Rehabilitation ◽  
Technical Capacity

Among end-effector robots for lower limb rehabilitation, systems based on Stewart–Gough platforms enable independent movement of each foot in six degrees of freedom. Nevertheless, control strategies described in recent literature have not been able to fully explore the potential of such a mechatronic system. In this work, we propose two novel approaches for controlling a gait simulator based on Stewart–Gough platforms. The first strategy provides the therapist direct control of each platform using movement data measured by wearable sensors. The following scheme is designed to improve the level of engagement of the patient by enabling a limited degree of control based on trunk inclination. Both strategies are designed to facilitate future studies in tele-rehabilitation settings. Experimental results have illustrated the feasibility of both control interfaces, either in terms of system performance or user subjective evaluation. Technical capacity to deploy in tele-rehabilitation was also verified in this work.

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