Limits...
Electromyography-Based Quantitative Representation Method for Upper-Limb Elbow Joint Angle in Sagittal Plane.

Pang M, Guo S, Huang Q, Ishihara H, Hirata H - J Med Biol Eng (2015)

Bottom Line: The results were calculated in real-time and used as control reference to drive an exoskeleton device bilaterally.The experimental results indicate that the proposed method can provide suitable prediction results with root-mean-square (RMS) errors of below 10° in continuous motion and RMS errors of below 10° in stepping motion with 20° and 30° increments.It is also easier to calibrate and implement.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Engineering, Kagawa University, Takamatsu, 761-0396 Japan.

ABSTRACT

This paper presents a quantitative representation method for the upper-limb elbow joint angle using only electromyography (EMG) signals for continuous elbow joint voluntary flexion and extension in the sagittal plane. The dynamics relation between the musculotendon force exerted by the biceps brachii muscle and the elbow joint angle is developed for a modified musculoskeletal model. Based on the dynamics model, a quadratic-like quantitative relationship between EMG signals and the elbow joint angle is built using a Hill-type-based muscular model. Furthermore, a state switching model is designed to stabilize the transition of EMG signals between different muscle contraction motions during the whole movement. To evaluate the efficiency of the method, ten subjects performed continuous experiments during a 4-day period and five of them performed a subsequent consecutive stepping test. The results were calculated in real-time and used as control reference to drive an exoskeleton device bilaterally. The experimental results indicate that the proposed method can provide suitable prediction results with root-mean-square (RMS) errors of below 10° in continuous motion and RMS errors of below 10° in stepping motion with 20° and 30° increments. It is also easier to calibrate and implement.

No MeSH data available.


Related in: MedlinePlus

Proposed state switching model. The four states are relaxation, flexion, holding, and extension. The switching thresholds for each state are determined in the calibration process
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4414936&req=5

Fig4: Proposed state switching model. The four states are relaxation, flexion, holding, and extension. The switching thresholds for each state are determined in the calibration process

Mentions: Although the relationship between EMG signals (muscle activation level) and elbow joint angle seems simple from Eq. (13), the actual relation is more complicated. Figure 4 shows one set of experimental results of normalized muscle activation level during the motion of elbow flexion and extension. There are four periods: relaxation period, elbow flexion period (part A in Fig. 3), holding period (part B in Fig. 3), and elbow extension period (part C in Fig. 3). In the flexion period, the activation level has a quadratic-like relation with the elbow joint angle, which corresponds to Eq. (14). In this period, the type of muscle contraction is concentric contraction. The interesting part is the connection portion between the flexion period and the holding period, where the musclotendon force decreases rapidly and then plateaus, which is similar to overshoot in control theory. This result can be explained by Eq. (2). During the motion of elbow flexion, the force or torque exerted by the muscle can be represented as:2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$F_{B} l\sin \,\theta = mg\sin \,\theta L + I\ddot{\theta }$$\end{document}FBlsinθ=mgsinθL+Iθ¨Fig. 3


Electromyography-Based Quantitative Representation Method for Upper-Limb Elbow Joint Angle in Sagittal Plane.

Pang M, Guo S, Huang Q, Ishihara H, Hirata H - J Med Biol Eng (2015)

Proposed state switching model. The four states are relaxation, flexion, holding, and extension. The switching thresholds for each state are determined in the calibration process
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4414936&req=5

Fig4: Proposed state switching model. The four states are relaxation, flexion, holding, and extension. The switching thresholds for each state are determined in the calibration process
Mentions: Although the relationship between EMG signals (muscle activation level) and elbow joint angle seems simple from Eq. (13), the actual relation is more complicated. Figure 4 shows one set of experimental results of normalized muscle activation level during the motion of elbow flexion and extension. There are four periods: relaxation period, elbow flexion period (part A in Fig. 3), holding period (part B in Fig. 3), and elbow extension period (part C in Fig. 3). In the flexion period, the activation level has a quadratic-like relation with the elbow joint angle, which corresponds to Eq. (14). In this period, the type of muscle contraction is concentric contraction. The interesting part is the connection portion between the flexion period and the holding period, where the musclotendon force decreases rapidly and then plateaus, which is similar to overshoot in control theory. This result can be explained by Eq. (2). During the motion of elbow flexion, the force or torque exerted by the muscle can be represented as:2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$F_{B} l\sin \,\theta = mg\sin \,\theta L + I\ddot{\theta }$$\end{document}FBlsinθ=mgsinθL+Iθ¨Fig. 3

Bottom Line: The results were calculated in real-time and used as control reference to drive an exoskeleton device bilaterally.The experimental results indicate that the proposed method can provide suitable prediction results with root-mean-square (RMS) errors of below 10° in continuous motion and RMS errors of below 10° in stepping motion with 20° and 30° increments.It is also easier to calibrate and implement.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Engineering, Kagawa University, Takamatsu, 761-0396 Japan.

ABSTRACT

This paper presents a quantitative representation method for the upper-limb elbow joint angle using only electromyography (EMG) signals for continuous elbow joint voluntary flexion and extension in the sagittal plane. The dynamics relation between the musculotendon force exerted by the biceps brachii muscle and the elbow joint angle is developed for a modified musculoskeletal model. Based on the dynamics model, a quadratic-like quantitative relationship between EMG signals and the elbow joint angle is built using a Hill-type-based muscular model. Furthermore, a state switching model is designed to stabilize the transition of EMG signals between different muscle contraction motions during the whole movement. To evaluate the efficiency of the method, ten subjects performed continuous experiments during a 4-day period and five of them performed a subsequent consecutive stepping test. The results were calculated in real-time and used as control reference to drive an exoskeleton device bilaterally. The experimental results indicate that the proposed method can provide suitable prediction results with root-mean-square (RMS) errors of below 10° in continuous motion and RMS errors of below 10° in stepping motion with 20° and 30° increments. It is also easier to calibrate and implement.

No MeSH data available.


Related in: MedlinePlus