Title
Detecting Elementary Arm Movements by Tracking Upper Limb Joint Angles with MARG Sensors.
Abstract
This paper reports an algorithm for the detection of three elementary upper limb movements i.e. reach and retrieve, bend the arm at the elbow and rotation of the arm about the long axis. We employ two MARG sensors, attached at the elbow and wrist, from which the kinematic properties (joint angles, position) of the upper arm and forearm are calculated through data fusion using a quaternion-based gradient-descent method and a 2-link model of the upper limb. By studying the kinematic patterns of the three movements on a small dataset, we derive discriminative features that are indicative of each movement; these are then used to formulate the proposed detection algorithm. Our novel approach of employing the joint angles and position to discriminate the three fundamental movements was evaluated in a series of experiments with 22 volunteers who participated in the study: 18 healthy subjects and 4 stroke survivors. In a controlled experiment, each volunteer was instructed to perform each movement a number of times. This was complimented by a semi-naturalistic experiment where the volunteers performed the same movements as subtasks of an activity that emulated the preparation of a cup of tea. In the stroke survivors group, the overall detection accuracy for all three movements was 93.75% and 83.00%, for the controlled and semi-naturalistic experiment respectively. The performance was higher in the healthy group where 96.85% of the tasks in the controlled experiment and 89.69% in the semi-naturalistic were detected correctly. Finally, the detection ratio remains close (6%) to the average value, for different task durations further attesting to the algorithms robustness.
Year
DOI
Venue
2016
10.1109/JBHI.2015.2431472
IEEE J. Biomedical and Health Informatics
Keywords
Field
DocType
orientation estimation,body-area networks,marg sensors,quaternion,upper limb movement,gradient-descent
Computer vision,Kinematics,Wrist,Elbow,Upper limb,Computer science,Accelerometer,Quaternion,Forearm,Artificial intelligence,Discriminative model
Journal
Volume
Issue
ISSN
PP
99
2168-2208
Citations 
PageRank 
References 
2
0.43
16
Authors
10