USABILITY EVALUATION OF AUTOMOBILE CONSOLE USING EMG ANALYSIS AND THREE-DIMENSIONAL MOTION ANALYSIS DESIGNING AUTOMOBILE CONSOLE FOR OLDER ADULTS

摘要

Using electromyographic (EMG) analysis and three-dimensional motion analysis, the usability of automobile consoles was evaluated as a function of age. The experimental factors were type of automobile consoles (A and B) and age young and older adults). The console B improved the console A so that it could be operated easily and comfortably with less workload and with less movement of left hand. EMG signals from trapezius muscle, deltoid, biceps brachii, triceps brachii, and pectoralis major were recorded during opening and closing consoles A and B with left hand. Simultaneously, the motion of wrist, elbow joint, and shoulder joint was recorded using a three-dimensional motion capture system with two cameras. EMG signals were analyzed using integral of EMG, mean of EMG, root mean square of EMG and mean power frequency (MPF). The three-dimensional motion analysis included normalized time series of velocity and acceleration of wrist, elbow joint, and shoulder joint, maximum of velocity and acceleration of these joints, normalized time series of elbow angle, maximum power of upper arm and forearm. From the viewpoints of physical workload evaluated by means of EMG measures, the console B was found to reduce the physical workload as compared with the console A. Especially for older adults, the console B reduced the workload. In accordance with the EMG based measures, the biomechanical data changed and verified that the workload of the console B became lower than that of the console A. The psychological rating on usability also showed that the console B was superior to the console B. However, the evaluation method proposed in this study pointed out that the console B could be improved so that the workload reduces further and the usability enhances. In such a way, the proposed method based on EMG analysis and motion analysis can be used to design a better automobile console system.