Validation of a New Dynamic Muscle Fatigue Model and DMET Analysis

Abstract

Automation in industries reduced the human effort, but still there are many manual tasks in industries which lead to musculo-skeletal disorder (MSD). Muscle fatigue is one of the reasons leading to MSD. The objective of this article is to experimentally validate a new dynamic muscle fatigue model taking cocontraction factor into consideration using electromyography (EMG) and Maximum voluntary contraction (MVC) data. A new model (Seth's model) is developed by introducing a co-contraction factor 'n' in R. Ma's dynamic muscle fatigue model. The experimental data of ten subjects are used to analyze the muscle activities and muscle fatigue during extension-flexion motion of the arm on a constant absolute value of the external load. The findings for co-contraction factor shows that the fatigue increases when co-contraction index decreases. The dynamic muscle fatigue model is validated using the MVC data, fatigue rate and co-contraction factor of the subjects. It has been found that with the increase in muscle fatigue, co-contraction index decreases and 90% of the subjects followed the exponential function predicted by fatigue model. The model is compared with other models on the basis of dynamic maximum endurance time (DMET). The co-contraction has significant effect on the muscle fatigue model and DMET. With the introduction of co-contraction factor DMET decreases by 25:9% as compare to R. Ma's Model.

Control design of a de-weighting upper-limb exoskeleton: extended-based fuzzy

“…Note that is restricted to 0, , hence the possible values exist in Quadrant I and Quadrant II. A condition statement is applied to obtain the final value of in (7). The condition statement is shown in Table 4.…”

“…Muscle fatigue could case reduction of power, lead to discomfort and pain. Furthermore, in a worst condition, muscle fatigue could lead to cumulative trauma disorder (CTD) and musculoskeletal disorder (MSD) [ 3], [7]. According to [8] the major forms of MSD in work-related morbidity include upper-limb disorders and low back pain.…”

Control design of a de-weighting upper-limb exoskeleton: extended-based fuzzy

“…Note that 𝜃 is restricted to 0, 𝜋 , hence the possible values exist in Quadrant I and Quadrant II. A condition statement is applied to obtain the final value of 𝜃 in (7). The condition statement is shown in Table 4.…”

Control Design of a De-Weighting Upper Limb Exoskeleton

“…It could cause the reduction of power, lead to discomfort and pain. In addition, muscle fatigue could lead to musculuskeletal disorder (MSD) and cumulative trauma disorder (CDT) [1]- [5].…”