The Motion Meaurement Of Human Upper-Limb Based On Electromagnetic Tracking System

The measurement and analysis of human motion is of great importance. It is widely used in rehabilitation, athletics, ergonomics, diagnosis, bionics and computer vision. In this paper, a motion measurement and analysis system for human upper limb based on Polhemus' electromagnetic tracking system is brought forth.In this paper the importance and methods of human motion measurement are discussed and the several kinds of measurement system used in human motion tracking and detection are introduced. A seven degrees-of-freedom kinematic model with three rigid bodies of human arm is built based on its anatomical structure and motion characteristic. The posture of the arm is described in terms of angles of rotations of the joints.The principle, method and other related questions of electromagnetic system are presented then. The electromagnetic system outputs positions and orientations of the sensors' coordinates relative to the source's coordinate system. According to anti-kinematic theory and rigid body dynamics, this paper brings forward an algorithm to use these data to calculate motion parameters of upper limb. And the algorithm is accomplished with Visual C++.Finally, an experiment was composed to verify the correctness of the algorithm and the program. With this foundation, the motion analysis system is used in the measurement of the motion of human arm in activities of daily life. The test shows that the measurement system based on electromagnetic system is an accurate and easy way for upper limb motion measurement.