Human body activity recognition using wearable inertial sensors integrated with a feature extraction–based machine-learning classification algorithm. (December 2022)

• Record Type: Journal Article
• Authors: Yen, Chih-Ta; Lin, Jia-De
• Other Names: Hsieh Wen-Hsiang guest-editor.; Garza-Reyes Jose Arturo guest-editor.; Wong Pak Kin guest-editor.
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 236:Number 14(2022)
• Page Start: 1820
• Page End: 1827
• Publication Date: 2022-12
• Subjects: Wearable device -- activity recognition -- inertial sensor -- machine learning -- classifier -- artificial neural network; Mechanical engineering -- Periodicals; Engineering -- Management -- Periodicals; Manufacturing processes -- Periodicals; 629.8
• DOI: 10.1177/0954405420937894
• Languages: English
• ISSNs: 0954-4054

Abstract

This study employed wearable inertial sensors integrated with an activity-recognition algorithm to recognize six types of daily activities performed by humans, namely walking, ascending stairs, descending stairs, sitting, standing, and lying. The sensor system consisted of a microcontroller, a three-axis accelerometer, and a three-axis gyro; the algorithm involved collecting and normalizing the activity signals. To simplify the calculation process and to maximize the recognition accuracy, the data were preprocessed through linear discriminant analysis; this reduced their dimensionality and captured their features, thereby reducing the feature space of the accelerometer and gyro signals; they were then verified through the use of six classification algorithms. The new contribution is that after feature extraction, data classification results indicated that an artificial neural network was the most stable and effective of the six algorithms. In the experiment, 20 participants equipped the wearable sensors on their waists to record the aforementioned six types of daily activities and to verify the effectiveness of the sensors. According to the cross-validation results, the combination of linear discriminant analysis and an artificial neural network was the most stable classification algorithm for data generalization; its activity-recognition accuracy was 87.37% on the training data and 80.96% on the test data.