Locomotor Sub-functions for Control of Assistive Wearable Robots

Sharbafi, Maziar Ahmad; Seyfarth, André; Zhao, Guoping

doi:10.3389/fnbot.2017.00044

Cited by 12 publications

(12 citation statements)

References 46 publications

(91 reference statements)

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“…8 shows clear reductions in thigh biarticular muscles activities, obtained by using leg force feedback in FMCH. This is in agreement with the implementation of VPP concept through FMCH and biarticular thigh actuation in simulated walking models [11] and a bipedal robot [54].…”

Section: Fmch Based Controller Has Higher Consistency In Emg Resposupporting

confidence: 89%

“…The novel FMCH based controller reacts to human action within a bio-inspired control framework. Previous experimental and simulation studies have shown that FMCH is a feasible control concept for balance [10], [11]. Here, we found that the exoskeleton can assist human by using the same feedback design.…”

Section: Fmch Based Controller Has Higher Consistency In Emg Resposupporting

confidence: 51%

“…Here we focus on human-inspired posture control approaches for exoskeletons and their benefits for walking. Posture control is one of the human locomtor subfunctions [11]. We believe that with posture control assistance not only stability but also energetics can be improved as locomotor sub-functions are internally connected with each other.…”

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confidence: 99%

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Bio-Inspired Balance Control Assistance Can Reduce Metabolic Energy Consumption in Human Walking

Zhao

Sharbafi

Vlutters

et al. 2019

IEEE Trans. Neural Syst. Rehabil. Eng.

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The amount of research on developing exoskeletons for human gait assistance has been growing in the recent years. However, the control design of exoskeletons for assisting human walking remains unclear. This paper presents a novel bio-inspired reflex-based control for assisting human walking. In this approach, the leg force is used as a feedback signal to adjust hip compliance. The effects of modulating hip compliance on walking gait is investigated through joint kinematics, leg muscle activations and overall metabolic costs for eight healthy young subjects. Reduction in the average metabolic cost and muscle activation are achieved with fixed hip compliance. Compared to the fixed hip compliance, improved assistance as reflected in more consistent reduction in muscle activities and more natural kinematic behaviour are obtained using the leg force feedback. Furthermore, smoother motor torques and less peak power are two additional advantages obtained by compliance modulation. The results show that the proposed control method which is inspired by human posture control can not only facilitate the human gait, but also reduce the exoskeleton power consumption. This demonstrates that the proposed bio-inspired controller allows a synergistic interaction between human and robot. Index Terms-Virtual pivot point, force modulated compliant hip, exoskeleton, bio-inspired control, human gait, assistive device.

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Section: Fmch Based Controller Has Higher Consistency In Emg Resposupporting

confidence: 89%

Section: Fmch Based Controller Has Higher Consistency In Emg Resposupporting

confidence: 51%

See 1 more Smart Citation

Bio-Inspired Balance Control Assistance Can Reduce Metabolic Energy Consumption in Human Walking

Zhao

Sharbafi

Vlutters

et al. 2019

IEEE Trans. Neural Syst. Rehabil. Eng.

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“…A Figura 3.1 mostra o fluxo de informações necessárias para produzir o andar. (Sharbafi et al, 2017).…”

Section: Visão Geral Do Movimentounclassified

2d Spatial Model of the Human Gait Single Support Phase Based on Predict Ive Dynamics

Oliveira¹,

Gonçalves²

2019

Proceedings of the 25th International Congress of Mechanical Engineering

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The simulation of human body movement is a valuable tool for different fields such as robotics and biomechanics. Even with the growing number of researches, there are still few groups in Brazil that work on developing models of human movement.Such simulation has been a challenging problem from a modeling and computational point of view. This dissertation brings a bibliographical review of concepts of structural dynamics and the main determinants of the dynamics of human walking. Four twodimensional models of increasing complexity found in the literature are initially analyzed to understand the influence of the various elements and degrees of freedom on the quality of the obtained results. Before introducing these models, an investigation of some kinematic variables, known as determinants of walking, is performed for the simple support phase. The simpler model considers an inverted pendulum, and then joints are added to simulate the hip, knee, ankle/foot, and finally the entire leg mechanism is replaced by a spring. The effects of successive additions of degrees of freedom are analyzed and the results are compared with Winter's experimental results for torques and reaction forces. Based on these analyzes, this work proposes a twodimensional model of human walking during the simple support phase (SSP) with seven degrees of freedom. The forces resulting from muscular actions are represented by torques at each joint. All masses of upper body segments are grouped. The model is based on inverse dynamics, with angular displacements being interpolated by 5th degree B-splines and the body kinematics is calculated using the Denavit-Hartenberg (DH) robotic formulation. The equations of motion are obtained based on a recursive Lagrangian formulation, due to its computational efficiency. An optimization problem is established to obtain the B-splines control points, where the objective function is defined by the dynamic effort. The constraints imposed on movement are of two types: the time-dependent constraints (torque/angle limits and dynamic stability defined by the PUC-Rio -Certificação Digital Nº 1712766/CA Zero Moment Point criterion) and the independent time constraints (initial and final state). The results of the model are favorably compared with Winter's experimental data, in particular the ground reaction forces.

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“…Resumidamente , a marcha humana possui 3 sub-funções: função apoio, que ocorre através do contato com o solo de maneira oposta à gravidade; função de balanço, por meio da rotação da perna contralateral, com um pequeno movimento axial para evitar o contato com o solo; função equilíbrio, que ocorre para garantir a estabilidade ao andar, uma vez que a maior parte da massa do corpo está no dorso, tornando-se naturalmente instável (Sharbafi et al, 2017).…”

Section: Visão Geral Do Movimentounclassified

Modelo Espacial 2d Da Fase De Apoio Simples Do Caminhar Humano Baseado Em Dinâmica Preditiva

OLIVEIRA¹

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The simulation of human body movement is a valuable tool for different fields such as robotics and biomechanics. Even with the growing number of researches, there are still few groups in Brazil that work on developing models of human movement. Such simulation has been a challenging problem from a modeling and computational point of view. This dissertation brings a bibliographical review of concepts of structural dynamics and the main determinants of the dynamics of human walking. Four twodimensional models of increasing complexity found in the literature are initially analyzed to understand the influence of the various elements and degrees of freedom on the quality of the obtained results. Before introducing these models, an investigation of some kinematic variables, known as determinants of walking, is performed for the simple support phase. The simpler model considers an inverted pendulum, and then joints are added to simulate the hip, knee, ankle/foot, and finally the entire leg mechanism is replaced by a spring. The effects of successive additions of degrees of freedom are analyzed and the results are compared with Winter's experimental results for torques and reaction forces. Based on these analyzes, this work proposes a twodimensional model of human walking during the simple support phase (SSP) with seven degrees of freedom. The forces resulting from muscular actions are represented by torques at each joint. All masses of upper body segments are grouped. The model is based on inverse dynamics, with angular displacements being interpolated by 5th degree B-splines and the body kinematics is calculated using the Denavit-Hartenberg (DH) robotic formulation. The equations of motion are obtained based on a recursive Lagrangian formulation, due to its computational efficiency. An optimization problem is established to obtain the B-splines control points, where the objective function is defined by the dynamic effort. The constraints imposed on movement are of two types: the time-dependent constraints (torque/angle limits and dynamic stability defined by the PUC-Rio-Certificação Digital Nº 1712766/CA Zero Moment Point criterion) and the independent time constraints (initial and final state). The results of the model are favorably compared with Winter's experimental data, in particular the ground reaction forces.

show abstract

Locomotor Sub-functions for Control of Assistive Wearable Robots

Cited by 12 publications

References 46 publications

Bio-Inspired Balance Control Assistance Can Reduce Metabolic Energy Consumption in Human Walking

Bio-Inspired Balance Control Assistance Can Reduce Metabolic Energy Consumption in Human Walking

2d Spatial Model of the Human Gait Single Support Phase Based on Predict Ive Dynamics

Modelo Espacial 2d Da Fase De Apoio Simples Do Caminhar Humano Baseado Em Dinâmica Preditiva

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