Research Of Human Motion Tracking Technology And Application Based On Data Fusion Of Optical Tracking System And IMU

It is of high application potential and great importance for measurement and simulation of human upper limb movement, which has been widely used in the fields of clinical diagnosis, rehabilitation engineering, physical training, ergonomics and virtual reality. The current mainstream techniques for measuring human upper limb movement consist of five categories, including mechanical, electromagnetic, video, optical and inertial tracking method, of which optically based technique is most commonly used. Large cost involved with high precision optical measurement equipment makes it less applicable to ordinary customers. On the other hand, performance of low-priced optical equipment hardly satisfies the high precision requirement. In this study, a data fusion based measurement technique has been proposed for measuring human body motions and applied in exoskeleton rehabilitation system. The proposed technique aims to improve performance of low-priced Optical Tracking System (OTS) in aspects of insufficient precision, complexity of data processing algorithm and manual post-processing stages in marker-missing and marker-mixing situations. Main works and research studies are summarized as follows:1. Based on the movement characteristics of upper limb and human modeling principles, a simplified model with four degrees of freedom has been proposed and parameterized using D-H method. The associated kinematic equations have been established and solving procedures for the upper limb joint angle have been completed. Furthermore, MATLAB Virtual Reality Toolbox has been utilized to build up the virtual reality model of human body, which is needed for the subsequent simulations.2. Multiple sets of experiments have been designed and conducted to evaluate and analyze the performance of the selected OTS. To deal with the problems of low measurement accuracy and immeasurable situations due to blockage of markers, a measurement scheme based on data fusion of OTS and Inertial Measurement Unit (IMU) was proposed with Kalman filter incorporated for predication and compensation. The experimental platform has been set up and multiple sets of date fusion experiments have been designed and carried out, including situations where optical markers were either blocked or unblocked, which helped verify the correctness of the proposed data fusion algorithm.3. The human motion measurement technique was applied in the rehabilitation exoskeleton system. Design for the entire system has been performed and corresponding software and hardware platforms have been established. Based on that, a series of experiments were carried out, which include simulation of virtual reality of the system and prototype testing. It can be shown through the experiment results that the system can perform online measurement of upper limbs movement and control the exoskeleton to accomplish the same action, which therefore validates the feasibility of the system solution.This paper explores the new method of human motion measurement and its application in rehabilitation field, providing theoretical and practical basis for more in-depth study in near future.