Abstract
A human arm can be described as a five degrees-of-freedom (DOF) serial manipulator. The fifth degree - rotation around the forearm axis only contributes to the wrist orientation. Hence, if it is ignored the elbow and wrist joint positions can be tracked using an upper arm orientation and the elbow joint angle. The paper presents a novel low-cost design of a 4-DOF human arm wearable tracker system for wireless dynamic tracking of upper limb position and orientation. The proposed design utilizes a single inertial measurement unit coupled with an Unscented Kalman filter for the upper arm orientation quaternion and a potentiometer sensor for elbow joint angle estimations. The presented arm tracker prototype implements wireless communication with the control PC for sensor data transmission and real-time visualization using a Blender open source 3D computer graphics software and was verified with an Xsens MVN motion tracking system. The demonstration video is available at the authors' research web-site www.alaris.kz.