title: Electromyography-Based Quantitative Representation Method for Upper-Limb Elbow Joint Angle in Sagittal Plane.
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.
authors.affiliation: Graduate School of Engineering, Kagawa University, Takamatsu, 761-0396 Japan.
authors.forename: Muye
authors.initials: M
authors.lastname: Pang
authors.affiliation: Department of Intelligent Mechanical Systems Engineering, Kagawa University, Takamatsu, 761-0396 Japan ; School of Life Science and Technology, Beijing Institute of Technology, Beijing, 100081 China.
authors.forename: Shuxiang
authors.initials: S
authors.lastname: Guo
authors.affiliation: School of Life Science and Technology, Beijing Institute of Technology, Beijing, 100081 China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Department of Intelligent Mechanical Systems Engineering, Kagawa University, Takamatsu, 761-0396 Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Ishihara
authors.affiliation: Department of Intelligent Mechanical Systems Engineering, Kagawa University, Takamatsu, 761-0396 Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hirata
keywords: Continuous representation; Electromyography (EMG); Hill-type model; State switching; Upper limb elbow joint