應用感測器於下肢動作之分析

Purpose: Using inertial measurement unit (IMU) to observe various modes of lower limb locomotion and different condition. Digital signals were used to identify signal characteristics, thereby identifying and distinguishing between various locomotion modes and intensity levels. We are going to find the most useful information for the walking pattern recognition (classification) to help improving the accuracy of assessment of daily physical activity. Methods: A wireless IMU was installed on the outside of shoes and tested in three locomotion (walking, running, and jumping) at two levels of intensity (low and high) and walking at 3 conditions (level ground, ascent/descent, ascending/descending stairs (2 different stair heights)) to observe the acceleration and foot angular velocity variations and characteristics of the curve variations in the anterioposterior, mediolateral, and superior-inferior directions. Results: Most interactions between intensity and locomotion were statistically significant, excepting the acceleration in the anterioposterior direction and on the horizontal plane. In addition, as the intensity increased, the values of all parameters increased. Moreover, the results indicated that the regular curve of the angular velocity in the frontal axis which were generated by each locomotion. In the comparison of different conditions only the angular velocity of dorsi/plantar flexion (Gyro-z axis) at heel-strike showed significant difference among the 7 conditions, only descent/level walking, and ascent/ascending stairs showed non-significantly different with each other. Conclusions: The acceleration in the anterioposterior direction and angular velocity in the frontal axis revealed many meaningful information in locomotion and conditions recognizing. We also can use dual-index (the acceleration of anteroposterior direction combine with angular velocity in the frontal axis) to help improving accuracy of locomotion and conditions recognizing. The sequence of the foot movements in different locomotion and under different conditions can be used to identify various locomotion and conditions by IMU sensor.