The Experts below are selected from a list of 139029 Experts worldwide ranked by ideXlab platform
Fumio Miyazaki - One of the best experts on this subject based on the ideXlab platform.
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Equilibrium Point based synergies that encode coordinates in task space a practical method for translating functional synergies from human to musculoskeletal robot arm
IEEE-RAS International Conference on Humanoid Robots, 2016Co-Authors: Fumiaki Yoshikawa, Mitsunori Uemura, Hiroaki Hirai, Fumio Miyazaki, Eichi Watanabe, Yuma Nagakawa, Akira Kuroiwa, Emerson Paul Grabke, Hermano Igo KrebsAbstract:A practical method for exploiting the neuromuscular coordination in a human arm posture to control a musculoskeletal robotic arm is proposed. The method enables the low-dimensional control of multiple muscles in the arm robot without considering the differences in the size and force balance between the human and artificial muscles. The central idea is based on the assumption that the Equilibrium Point (EP) of an arm is always located at its endPoint position while maintaining the posture on the horizontal plane. The mathematical formulation obtained using this physical constraint leads to the EP-based synergies that encode the polar coordinates in the task space. We tested this theory by extracting EP-based synergies from electromyography activities during human posture maintenance and implementing them for a musculoskeletal robotic arm. The results suggest EP-based synergies could be functional modules of muscle mechanical impedance which is an essential primitive for human motor control.
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Exploiting invariant structure for controlling multiple muscles in anthropomorphic legs: II. Experimental evidence for three Equilibrium-Point-based synergies during human pedaling
2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), 2016Co-Authors: Eichi Watanabe, Mitsunori Uemura, Hiroaki Hirai, Fumio Miyazaki, Fumiaki Yoshikawa, Yuma Nagakawa, Akira Kuroiwa, Emerson Paul Grabke, Hermano Igo KrebsAbstract:Developing a musculoskeletal robot with multiple muscles is important for not only establishing a novel robot that achieves coordination with a human but also in understanding the framework of motor control in the human body. Our pioneering work proposed a biologically inspired control framework for multiple redundant muscles; however, very few practical results have been reported on controlling a musculoskeletal robot. This study focused on confirming the usability of the proposed biologically inspired control framework, which is referred to as Equilibrium-Point (EP)-based synergyies and is expressed by the activation balance of agonist-antagonist muscle pairs. Electromyography data obtained from the pedaling task of five subjects were analyzed based on the concept of the EP-based synergies, and were then used to control the musculoskeletal lower limb robot. Three EP-based synergies obtained from all the five subjects indicated that the musculoskeletal robot achieved forward pedaling. This indicates the utility of the EP-based synergies as well as the modularity of motor control in humans.
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a novel muscle synergy extraction method to explain the Equilibrium Point trajectory and endPoint stiffness during human upper limb movements on a horizontal plane
IEEE International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Pipatthana Phatiwuttipat, Keitaro Koba, Yuto Yamashita, Kenta Murakami, Mitsunori Uemura, Hiroaki Hirai, Fumio MiyazakiAbstract:Based on the idea of synergy to explore the building blocks of movements, this study focused on the muscle space for reaching movements by human upper limbs on a horizontal plane to estimate the relationship among muscle synergies, Equilibrium-Point (EP) trajectories, and endPoint stiffness in two ways: (1) a novel estimation method that analyzes electromyographic signals under the concept of agonist-antagonist (A-A) muscle pairs and (2) a conventional estimation method that uses mechanical perturbations. The experimental results suggest that (1) muscle activities of reaching movements by human upper limbs are represented by only three functional muscle synergies; (2) each muscle synergy balances the coacti-vations of A-A muscle pairs; (3) two of the muscle synergies are invariant bases that form an EP trajectory described in polar coordinates centered on a shoulder joint, where one is a composite unit for radial movement and the other is for angular movement; and (4) the third muscle synergy is the invariant basis for additional adjustment of the endPoint stiffness and has some influence on the direction and size of the endPoint stiffness ellipse.
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Equilibrium Point control of human elbow joint movement under isometric environment by using multichannel functional electrical stimulation
Frontiers in Neuroscience, 2014Co-Authors: Kazuhiro Matsui, Yuto Yamashita, Mitsunori Uemura, Hiroaki Hirai, Yasuo Hishii, Kazuya Maegaki, Fumio MiyazakiAbstract:Functional electrical stimulation (FES) is considered an effective technique for aiding quadriplegic persons. However, the human musculoskeletal system has highly nonlinearity and redundancy. It is thus difficult to stably and accurately control limbs using FES. In this paper, we propose a simple FES method that is consistent with the motion-control mechanism observed in humans. We focus on joint motion by a pair of agonist-antagonist muscles of the musculoskeletal system, and define the"electrical agonist-antagonist muscle ratio (EAA ratio)" and "electrical agonist-antagonist muscle activity (EAA activity)" in light of the agonist-antagonist muscle ratio and agonist-antagonist muscle activity, respectively, to extract the Equilibrium Point and joint stiffness from electromyography (EMG) signals. These notions, the agonist-antagonist muscle ratio and agonist-antagonist muscle activity, are based on the hypothesis that the Equilibrium Point and stiffness of the agonist-antagonist motion system are controlled by the central nervous system. We derived the transfer function between the input EAA ratio and force output of the end-Point. We performed some experiments in an isometric environment using six subjects. This transfer-function model is expressed as a cascade-coupled dead time element and a second-order system. High-speed, high-precision, smooth control of the hand force were achieved through the agonist-antagonist muscle stimulation pattern determined by this transfer function model.
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Novel Equilibrium-Point control of agonist-antagonist system with pneumatic artificial muscles
2012 IEEE International Conference on Robotics and Automation, 2012Co-Authors: Yohei Ariga, Mitsunori Uemura, Hiroaki Hirai, Hang T.t. Pham, Fumio MiyazakiAbstract:This paper presents a novel method for controlling a single-joint robot arm driven by two pneumatic artificial muscles (PAMs). We introduce the concepts of the agonist-antagonist muscle-pairs ratio (A-A ratio) and the agonist-antagonist muscle-pairs activity (A-A activity), and demonstrate that our concepts enable separate linear control of the Equilibrium joint angle and joint stiffness. We also discuss our approach in comparison with the Equilibrium-Point (EP) hypothesis.
Hiroaki Hirai - One of the best experts on this subject based on the ideXlab platform.
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exploiting the invariant structure for controlling multiple muscles in anthropomorphic legs iii reproducing hemiparetic walking from Equilibrium Point based synergies
IEEE International Conference on Rehabilitation Robotics, 2019Co-Authors: Eichi Watanabe, Hiroaki Hirai, Kohei Kozasa, Ryo Fujihara, Keishi Yoshida, Hiroaki Naritomi, Hermano Igo KrebsAbstract:In the development of a robotic therapy system, tests must be first run to guarantee safety and performance of the system before actual human trials. Lower–limb robotic therapy system has an inherit injury risk and a human–like stunt robot is desirable. This study proposes such an alternative: anthropomorphic legs with a bio–inspired control method affording a human–like test bench for the robotic therapy system. Electromyography (EMG) of a mildly hemiparetic stroke patient was measured during body–weight–supported treadmill walking. The motor strategy of the hemiparetic gait was extracted from the EMG data and applied to the control of the anthropomorphic legs. We employed the concept of Equilibrium Point (EP) to extract motor synergies and strategy. The EP– based synergies expressed by the composites of muscle mechanical impedance clarified motor strategy including aspects related to the impedance and virtual trajectory. Results show that the EP–based synergies were able to characterize neuromuscular patterns of pathological gait. The anthropomorphic legs were able to reproduce patient’s gait by mimicking the EP–based synergies.
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Equilibrium Point based synergies that encode coordinates in task space a practical method for translating functional synergies from human to musculoskeletal robot arm
IEEE-RAS International Conference on Humanoid Robots, 2016Co-Authors: Fumiaki Yoshikawa, Mitsunori Uemura, Hiroaki Hirai, Fumio Miyazaki, Eichi Watanabe, Yuma Nagakawa, Akira Kuroiwa, Emerson Paul Grabke, Hermano Igo KrebsAbstract:A practical method for exploiting the neuromuscular coordination in a human arm posture to control a musculoskeletal robotic arm is proposed. The method enables the low-dimensional control of multiple muscles in the arm robot without considering the differences in the size and force balance between the human and artificial muscles. The central idea is based on the assumption that the Equilibrium Point (EP) of an arm is always located at its endPoint position while maintaining the posture on the horizontal plane. The mathematical formulation obtained using this physical constraint leads to the EP-based synergies that encode the polar coordinates in the task space. We tested this theory by extracting EP-based synergies from electromyography activities during human posture maintenance and implementing them for a musculoskeletal robotic arm. The results suggest EP-based synergies could be functional modules of muscle mechanical impedance which is an essential primitive for human motor control.
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Exploiting invariant structure for controlling multiple muscles in anthropomorphic legs: II. Experimental evidence for three Equilibrium-Point-based synergies during human pedaling
2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), 2016Co-Authors: Eichi Watanabe, Mitsunori Uemura, Hiroaki Hirai, Fumio Miyazaki, Fumiaki Yoshikawa, Yuma Nagakawa, Akira Kuroiwa, Emerson Paul Grabke, Hermano Igo KrebsAbstract:Developing a musculoskeletal robot with multiple muscles is important for not only establishing a novel robot that achieves coordination with a human but also in understanding the framework of motor control in the human body. Our pioneering work proposed a biologically inspired control framework for multiple redundant muscles; however, very few practical results have been reported on controlling a musculoskeletal robot. This study focused on confirming the usability of the proposed biologically inspired control framework, which is referred to as Equilibrium-Point (EP)-based synergyies and is expressed by the activation balance of agonist-antagonist muscle pairs. Electromyography data obtained from the pedaling task of five subjects were analyzed based on the concept of the EP-based synergies, and were then used to control the musculoskeletal lower limb robot. Three EP-based synergies obtained from all the five subjects indicated that the musculoskeletal robot achieved forward pedaling. This indicates the utility of the EP-based synergies as well as the modularity of motor control in humans.
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a novel muscle synergy extraction method to explain the Equilibrium Point trajectory and endPoint stiffness during human upper limb movements on a horizontal plane
IEEE International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Pipatthana Phatiwuttipat, Keitaro Koba, Yuto Yamashita, Kenta Murakami, Mitsunori Uemura, Hiroaki Hirai, Fumio MiyazakiAbstract:Based on the idea of synergy to explore the building blocks of movements, this study focused on the muscle space for reaching movements by human upper limbs on a horizontal plane to estimate the relationship among muscle synergies, Equilibrium-Point (EP) trajectories, and endPoint stiffness in two ways: (1) a novel estimation method that analyzes electromyographic signals under the concept of agonist-antagonist (A-A) muscle pairs and (2) a conventional estimation method that uses mechanical perturbations. The experimental results suggest that (1) muscle activities of reaching movements by human upper limbs are represented by only three functional muscle synergies; (2) each muscle synergy balances the coacti-vations of A-A muscle pairs; (3) two of the muscle synergies are invariant bases that form an EP trajectory described in polar coordinates centered on a shoulder joint, where one is a composite unit for radial movement and the other is for angular movement; and (4) the third muscle synergy is the invariant basis for additional adjustment of the endPoint stiffness and has some influence on the direction and size of the endPoint stiffness ellipse.
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Equilibrium Point control of human elbow joint movement under isometric environment by using multichannel functional electrical stimulation
Frontiers in Neuroscience, 2014Co-Authors: Kazuhiro Matsui, Yuto Yamashita, Mitsunori Uemura, Hiroaki Hirai, Yasuo Hishii, Kazuya Maegaki, Fumio MiyazakiAbstract:Functional electrical stimulation (FES) is considered an effective technique for aiding quadriplegic persons. However, the human musculoskeletal system has highly nonlinearity and redundancy. It is thus difficult to stably and accurately control limbs using FES. In this paper, we propose a simple FES method that is consistent with the motion-control mechanism observed in humans. We focus on joint motion by a pair of agonist-antagonist muscles of the musculoskeletal system, and define the"electrical agonist-antagonist muscle ratio (EAA ratio)" and "electrical agonist-antagonist muscle activity (EAA activity)" in light of the agonist-antagonist muscle ratio and agonist-antagonist muscle activity, respectively, to extract the Equilibrium Point and joint stiffness from electromyography (EMG) signals. These notions, the agonist-antagonist muscle ratio and agonist-antagonist muscle activity, are based on the hypothesis that the Equilibrium Point and stiffness of the agonist-antagonist motion system are controlled by the central nervous system. We derived the transfer function between the input EAA ratio and force output of the end-Point. We performed some experiments in an isometric environment using six subjects. This transfer-function model is expressed as a cascade-coupled dead time element and a second-order system. High-speed, high-precision, smooth control of the hand force were achieved through the agonist-antagonist muscle stimulation pattern determined by this transfer function model.
Benjamin Kuipers - One of the best experts on this subject based on the ideXlab platform.
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autonomous person pacing and following with model predictive Equilibrium Point control
International Conference on Robotics and Automation, 2013Co-Authors: Jong-jin Park, Benjamin KuipersAbstract:The ability to follow or move alongside a person is a necessary skill for an autonomous mobile agent that works with human users. To accomplish the task, the robot must be able to track and follow the person it is accompanying while maneuvering through obstacles without collision. Also, the robot must be able to respect user preferences and exhibit behaviors that are intuitive and socially acceptable. That is, the robot is required to make complex decisions on-line, in environments that are almost always dynamic and uncertain in the presence of pedestrians. This paper discusses a versatile motion planning algorithm for person pacing, which refers to the capability to walk next to another person at user-preferred distance and orientation [1]. The algorithm is based on the Model Predictive Equilibrium Point Control (MPEPC) framework [2] which allows a robot to navigate gracefully in dynamic, uncertain, and structured environments. We show that with a simple task description for person pacing, an agent with the MPEPC navigation algorithm can make intelligent decisions on-line, maximizing the expected progress toward achieving the task while minimizing the action cost and the probability of collision. We present navigation examples generated from real data traces, where a wheelchair robot exhibits very reasonable behaviors across a wide range of situations.
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Robot navigation with model predictive Equilibrium Point control
IEEE International Conference on Intelligent Robots and Systems, 2012Co-Authors: Jong-jin Park, Collin Johnson, Benjamin KuipersAbstract:An autonomous vehicle intended to carry passengers must be able to generate trajectories on-line that are safe, smooth and comfortable. Here, we propose a strategy for robot navigation in a structured, dynamic indoor environment, where the robot reasons about the near future and makes a locally optimal decision at each time step.
Mitsunori Uemura - One of the best experts on this subject based on the ideXlab platform.
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Equilibrium Point based synergies that encode coordinates in task space a practical method for translating functional synergies from human to musculoskeletal robot arm
IEEE-RAS International Conference on Humanoid Robots, 2016Co-Authors: Fumiaki Yoshikawa, Mitsunori Uemura, Hiroaki Hirai, Fumio Miyazaki, Eichi Watanabe, Yuma Nagakawa, Akira Kuroiwa, Emerson Paul Grabke, Hermano Igo KrebsAbstract:A practical method for exploiting the neuromuscular coordination in a human arm posture to control a musculoskeletal robotic arm is proposed. The method enables the low-dimensional control of multiple muscles in the arm robot without considering the differences in the size and force balance between the human and artificial muscles. The central idea is based on the assumption that the Equilibrium Point (EP) of an arm is always located at its endPoint position while maintaining the posture on the horizontal plane. The mathematical formulation obtained using this physical constraint leads to the EP-based synergies that encode the polar coordinates in the task space. We tested this theory by extracting EP-based synergies from electromyography activities during human posture maintenance and implementing them for a musculoskeletal robotic arm. The results suggest EP-based synergies could be functional modules of muscle mechanical impedance which is an essential primitive for human motor control.
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Exploiting invariant structure for controlling multiple muscles in anthropomorphic legs: II. Experimental evidence for three Equilibrium-Point-based synergies during human pedaling
2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), 2016Co-Authors: Eichi Watanabe, Mitsunori Uemura, Hiroaki Hirai, Fumio Miyazaki, Fumiaki Yoshikawa, Yuma Nagakawa, Akira Kuroiwa, Emerson Paul Grabke, Hermano Igo KrebsAbstract:Developing a musculoskeletal robot with multiple muscles is important for not only establishing a novel robot that achieves coordination with a human but also in understanding the framework of motor control in the human body. Our pioneering work proposed a biologically inspired control framework for multiple redundant muscles; however, very few practical results have been reported on controlling a musculoskeletal robot. This study focused on confirming the usability of the proposed biologically inspired control framework, which is referred to as Equilibrium-Point (EP)-based synergyies and is expressed by the activation balance of agonist-antagonist muscle pairs. Electromyography data obtained from the pedaling task of five subjects were analyzed based on the concept of the EP-based synergies, and were then used to control the musculoskeletal lower limb robot. Three EP-based synergies obtained from all the five subjects indicated that the musculoskeletal robot achieved forward pedaling. This indicates the utility of the EP-based synergies as well as the modularity of motor control in humans.
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a novel muscle synergy extraction method to explain the Equilibrium Point trajectory and endPoint stiffness during human upper limb movements on a horizontal plane
IEEE International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Pipatthana Phatiwuttipat, Keitaro Koba, Yuto Yamashita, Kenta Murakami, Mitsunori Uemura, Hiroaki Hirai, Fumio MiyazakiAbstract:Based on the idea of synergy to explore the building blocks of movements, this study focused on the muscle space for reaching movements by human upper limbs on a horizontal plane to estimate the relationship among muscle synergies, Equilibrium-Point (EP) trajectories, and endPoint stiffness in two ways: (1) a novel estimation method that analyzes electromyographic signals under the concept of agonist-antagonist (A-A) muscle pairs and (2) a conventional estimation method that uses mechanical perturbations. The experimental results suggest that (1) muscle activities of reaching movements by human upper limbs are represented by only three functional muscle synergies; (2) each muscle synergy balances the coacti-vations of A-A muscle pairs; (3) two of the muscle synergies are invariant bases that form an EP trajectory described in polar coordinates centered on a shoulder joint, where one is a composite unit for radial movement and the other is for angular movement; and (4) the third muscle synergy is the invariant basis for additional adjustment of the endPoint stiffness and has some influence on the direction and size of the endPoint stiffness ellipse.
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Equilibrium Point control of human elbow joint movement under isometric environment by using multichannel functional electrical stimulation
Frontiers in Neuroscience, 2014Co-Authors: Kazuhiro Matsui, Yuto Yamashita, Mitsunori Uemura, Hiroaki Hirai, Yasuo Hishii, Kazuya Maegaki, Fumio MiyazakiAbstract:Functional electrical stimulation (FES) is considered an effective technique for aiding quadriplegic persons. However, the human musculoskeletal system has highly nonlinearity and redundancy. It is thus difficult to stably and accurately control limbs using FES. In this paper, we propose a simple FES method that is consistent with the motion-control mechanism observed in humans. We focus on joint motion by a pair of agonist-antagonist muscles of the musculoskeletal system, and define the"electrical agonist-antagonist muscle ratio (EAA ratio)" and "electrical agonist-antagonist muscle activity (EAA activity)" in light of the agonist-antagonist muscle ratio and agonist-antagonist muscle activity, respectively, to extract the Equilibrium Point and joint stiffness from electromyography (EMG) signals. These notions, the agonist-antagonist muscle ratio and agonist-antagonist muscle activity, are based on the hypothesis that the Equilibrium Point and stiffness of the agonist-antagonist motion system are controlled by the central nervous system. We derived the transfer function between the input EAA ratio and force output of the end-Point. We performed some experiments in an isometric environment using six subjects. This transfer-function model is expressed as a cascade-coupled dead time element and a second-order system. High-speed, high-precision, smooth control of the hand force were achieved through the agonist-antagonist muscle stimulation pattern determined by this transfer function model.
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Novel Equilibrium-Point control of agonist-antagonist system with pneumatic artificial muscles
2012 IEEE International Conference on Robotics and Automation, 2012Co-Authors: Yohei Ariga, Mitsunori Uemura, Hiroaki Hirai, Hang T.t. Pham, Fumio MiyazakiAbstract:This paper presents a novel method for controlling a single-joint robot arm driven by two pneumatic artificial muscles (PAMs). We introduce the concepts of the agonist-antagonist muscle-pairs ratio (A-A ratio) and the agonist-antagonist muscle-pairs activity (A-A activity), and demonstrate that our concepts enable separate linear control of the Equilibrium joint angle and joint stiffness. We also discuss our approach in comparison with the Equilibrium-Point (EP) hypothesis.
Mark L. Latash - One of the best experts on this subject based on the ideXlab platform.
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synergies in the space of control variables within the Equilibrium Point hypothesis
Neuroscience, 2016Co-Authors: Satyajit Ambike, Vladimir M Zatsiorsky, Daniela Mattos, Mark L. LatashAbstract:We use an approach rooted in the recent theory of synergies to analyze possible co-variation between two hypothetical control variables involved in finger force production based on the Equilibrium-Point (EP) hypothesis. These control variables are the referent coordinate (R) and apparent stiffness (C) of the finger. We tested a hypothesis that inter-trial co-variation in the {R; C} space during repeated, accurate force production trials stabilizes the fingertip force. This was expected to correspond to a relatively low amount of inter-trial variability affecting force and a high amount of variability keeping the force unchanged. We used the "inverse piano" apparatus to apply small and smooth positional perturbations to fingers during force production tasks. Across trials, R and C showed strong co-variation with the data Points lying close to a hyperbolic curve. Hyperbolic regressions accounted for over 99% of the variance in the {R; C} space. Another analysis was conducted by randomizing the original {R; C} data sets and creating surrogate data sets that were then used to compute predicted force values. The surrogate sets always showed much higher force variance compared to the actual data, thus reinforcing the conclusion that finger force control was organized in the {R; C} space, as predicted by the EP hypothesis, and involved co-variation in that space stabilizing total force.
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stages in learning motor synergies a view based on the Equilibrium Point hypothesis
Human Movement Science, 2010Co-Authors: Mark L. LatashAbstract:This review describes a novel view on stages in motor learning based on recent developments of the notion of synergies, the uncontrolled manifold hypothesis, and the Equilibrium-Point hypothesis (referent configuration) that allow to merge these notions into a single scheme of motor control. The principle of abundance and the principle of minimal final action form the foundation for analyses of natural motor actions performed by redundant sets of elements. Two main stages of motor learning are introduced corresponding to (1) discovery and strengthening of motor synergies stabilizing salient performance variable(s) and (2) their weakening when other aspects of motor performance are optimized. The first stage may be viewed as consisting of two steps, the elaboration of an adequate referent configuration trajectory and the elaboration of multi-joint (multi-muscle) synergies stabilizing the referent configuration trajectory. Both steps are expected to lead to more variance in the space of elemental variables that is compatible with a desired time profile of the salient performance variable ("good variability"). Adjusting control to other aspects of performance during the second stage (for example, esthetics, energy expenditure, time, fatigue, etc.) may lead to a drop in the "good variability". Experimental support for the suggested scheme is reviewed.
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motor synergies and the Equilibrium Point hypothesis
Motor Control, 2010Co-Authors: Mark L. LatashAbstract:The article offers a way to unite three recent developments in the field of motor control and coordination: (1) The notion of synergies is introduced based on the principle of motor abundance; (2) The uncontrolled manifold hypothesis is described as offering a computational framework to identify and quantify synergies; and (3) The Equilibrium-Point hypothesis is described for a single muscle, single joint, and multijoint systems. Merging these concepts into a single coherent scheme requires focusing on control variables rather than performance variables. The principle of minimal final action is formulated as the guiding principle within the referent configuration hypothesis. Motor actions are associated with setting two types of variables by a controller, those that ultimately define average performance patterns and those that define associated synergies. Predictions of the suggested scheme are reviewed, such as the phenomenon of anticipatory synergy adjustments, quick actions without changes in synergies, atypical synergies, and changes in synergies with practice. A few models are briefly reviewed.
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evolution of motor control from reflexes and motor programs to the Equilibrium Point hypothesis
Journal of Human Kinetics, 2008Co-Authors: Mark L. LatashAbstract:This brief review analyzes the evolution of motor control theories along two lines that emphasize active (motor programs) and reactive (reflexes) features of voluntary movements. It suggests that the only contemporary hypothesis that integrates both approaches in a fruitful way is the Equilibrium-Point hypothesis. Physical, physiological, and behavioral foundations of the EP-hypothesis are considered as well as relations between the EP-hypothesis and the recent developments of the notion of motor synergies. The paper ends with a brief review of the criticisms of the EP-hypothesis and challenges that the hypothesis faces at this time.
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Testing hypotheses and the advancement of science: recent attempts to falsify the Equilibrium Point hypothesis
Experimental Brain Research, 2005Co-Authors: Anatol G. Feldman, Mark L. LatashAbstract:Criticisms of the Equilibrium Point (EP) hypothesis have recently appeared that are based on misunderstandings of some of its central notions. Starting from such interpretations of the hypothesis, incorrect predictions are made and tested. When the incorrect predictions prove false, the hypothesis is claimed to be falsified. In particular, the hypothesis has been rejected based on the wrong assumptions that it conflicts with empirically defined joint stiffness values or that it is incompatible with violations of equifinality under certain velocity-dependent perturbations. Typically, such attempts use notions describing the control of movements of artificial systems in place of physiologically relevant ones. While appreciating constructive criticisms of the EP hypothesis, we feel that incorrect interpretations have to be clarified by reiterating what the EP hypothesis does and does not predict. We conclude that the recent claims of falsifying the EP hypothesis and the calls for its replacement by EMG-force control hypothesis are unsubstantiated. The EP hypothesis goes far beyond the EMG-force control view. In particular, the former offers a resolution for the famous posture-movement paradox while the latter fails to resolve it.
