Estimation of the upper limb lifting movement under varying weight and movement speed

This paper aims to estimate physical human intention during lifting movement from EMG signals. Subjects conducted periodic target following up/down movement which the target moves in sinusoidal speed profile on sagittal plane. The movement conditions vary with target speed, 0.2Hz, 0.3Hz, 0.4Hz, and 0.5Hz, and with weight, 1.5kg, 3kg, 4.5kg, and no load. The difference between loaded and unloaded lifting movement in muscle contraction level is investigated and a simple mathematical method to recognize the motor intention and load condition is suggested. Through the logistic regression model, movement direction was estimated with over 80% accuracy. In addition, it was found that the pattern of TCL is similar to the joint angle in unloaded condition and to the angular speed in loaded condition.