| Testing and analysis of human motion is cross-frontier research area of science and engineering, which is related to human anatomy, human physiology, biomathematics, biomechanics, mechanics, and ergonomics, etc. and thus it is a highly comprehensive developing interdisciplinary research, in which the concepts and methods of biology, mathematics and engineering are needed to be applied.This dissertation, supported by Key Program of the National Natural Science Foundation of China (Grant No. 50635030), mainly focused on the study of human locomotion. From the viewpoints of biology, anatomy, and mechanics, the human multiple rigid-body kinematic models were established applying the theory of inverse kinematics. And a novel infrared reflective tracking marker system had been constructed using stereophotogrammetry techniques. So the 3-dimensional human motion had been successfully measured by the optical motion capture technology and the innovative experimental testing method. Based on QTM software as well as the further development and expansion modules of SMAS software, the kinematic parameters of human motion were successfully processed and calculated. And then, the biological coupling behavior and the kinematic coupling characteristics of the upper limb, the lower limb and the spine of human could be detailed analyzed, and consequently, the behavior and basic rules of human 3-dimensional motion were finally revealed. This research may provide the effective research methods and technical means for many research fields, such as biomimetic engineering, ergonomics, aeronautics and astronautics, defense and military, biomedicine engineering and sports competition, etc. The main research works and obtained conclusions of this dissertation are as follows:1. Based on the mechanical theory and inverse kinematics, human multiple rigid body kinematic models were successfully established. We introduced the mechanistic methods into the research of human motion, and simplified different segments of human body as rigid bodies, and the joints of human body as hinges. Thus, the human multiple rigid body kinematic models included 17 segments and 16 joints were established according to the bone structure and motion characteristics of human body. The models were composed of the segment-joint distributed model, segmental marker model, functional joint rotation center position model, human locomotor global coordinate system and segmental anatomical local coordinate systems. Each part of the models was described by physical methods, and the solution methods of the models were also introduced by the mathematic methods, such as the Spatial Coordinate Transformation, the Euler Transformation and the Finite Difference, etc.2. Based on the parameter requirements of the kinematic models, a novel infrared reflective tracking marker system had been constructed using stereophotogrammetry techniques. The system included 17 tracking sub-systems of the segmental motion of human body and 1 static calibration wand. Each tracking sub-system included a static anatomical landmark system and a dynamic technical marker cluster system. The whole tracking marker system was composed of 130 markers in total, including 42 markers of 5 segments of trunk and the spine, 34 markers of 6 segments of upper limbs, and 54 markers of 6 segments of lower limbs (please see appendix A). Depending on the interaction between these various sub-systems, we could carry out a series of experimental tests innovatively.3. Due to the developed innovative experimental testing methods, the 3-dimensional human motion had been successfully measured. By building up testing platform of motion capture system, using the novel infrared reflective tracking marker system, and utilizing a series of new techniques, such as the complementarities of static anatomical landmark and static calibration wand, the mapping of static anatomical landmark and dynamic technical marker cluster, dynamic calibration of the functional joint motion, etc., the 3-dimensional human motion experiments of eight Asian healthy mature men were successfully carried out. Under the same experimental conditions, each subject had been measured for six kinds of state of motion, including three kinds of velocities(slow, normal, fast) and two kinds of motion gait(walking, running), and ten repeated trials were accomplished in each kind of state of motion.4. Based on QTM software and SMAS software, the experimental data were successfully processed and calculated. Firstly, we utilized QTM software to actualize 3-dimensional data construction, data error correction and data calibration, etc. Secondly, we applied SMAS software to realize digital filter, and data dimensionality reduce, etc. Finally, based on the further development and expansion modules of SMAS software, we successfully calculated the experimental data of the upper limbs, the lower limbs and the spine, and obtained the kinematic parameters of human motion, including 3D displacements, angles of the segments, and the joints of human body.5. The biological coupling behavior and the kinematic coupling characteristics of the upper limbs and the lower limbs of human were analyzed. Firstly, motion cycle, motion phase and average velocity of human motion were calculated. The results showed that, in six kinds of different motion conditions (from slow walking to fast running), the motion cycle and the motion stance phase were gradually reduced, while the average velocities were gradually increased. Secondly, the biological coupling behavior of the upper limbs and the lower limbs were investigated. The results showed that, the upper and lower limbs of human showed significant characteristic of joint motion. It indicated that flexion/extension was the main motion feature in sagittal plane, while the lateral bending in coronal plane and the axial rotation in transverse plane were subsidiary motions. Finally, the kinematic coupling characteristics of the upper limbs and the lower limbs of human were analyzed. The results were as follows: 1) the kinematic coupling characteristics of upper limbs motion. The elbow joint and shoulder joint displayed synchronizing vertical displacement motion trend to achieve the transformation of kinetic energy to potential energy during the gait cycle; For angle-angle movements of joints, the flexion/extension-lateral bending of shoulder joint, the flexion/extension-axial rotation of shoulder joint, the flexion/extension of elbow joint-the flexion/extension of shoulder joint, and the flexion/extension of elbow joint-the axial rotation of shoulder joint all showed characteristics of coordinated kinematic coupling . And these coupling characteristics maintained the coordination, stability and balance of the human body during human gait locomotion. 2) The kinematic coupling characteristics of lower limbs motion. The angle-angle movements of the lower limbs, such as the ankle joint and the knee joint performed the synchronizing vertical displacement motion trend; the flexion/extension-lateral bending of shoulder joint, the flexion/extension-axial rotation of hip joint, the flexion/extension of ankle joint-the flexion/extension of knee joint, the flexion/extension of knee joint-the flexion/extension of hip joint, and the flexion/extension of knee joint-the axial rotation of hip joint all showed characteristics of coordinated kinematic coupling , which maintained the lower limbs to carry out the complex movements in a complete gait cycle motion, such as braking, balance, driving, etc.6. The biological coupling behavior and the kinematic coupling characteristics of the spine of human were analyzed. Firstly, the shape changes of the whole spinal were investigated in a complete gait cycle motion. The results demonstrated that the spine shape changed a little in the sagittal plane, but it periodically changed in the coronal plane and the transverse plane. Secondly, we systematically explored the biological coupling behavior of the human spine motion. The results showed that, the spine motion of human possessed remarkable features of segmental motion. It indicated that little motion of the segments in the sagittal plane was detected, while significant motion in the coronal plane and the transverse plane was discovered. Finally, the kinematic coupling characteristics of human spine were analyzed. Each segmental motion of the cervical, thoracic and lumbar performed coordinated kinematic characteristics in vertical displacement related to lateral displacement. In addition, the angle-angle segmental motion of the spine, such as the lateral bending-axial rotation of thoracic, the lateral bending-axial rotation of lumbar, the axial rotation of thoracic-the axial rotation of lumbar, the axial rotation of lumbar-the axial rotation of hip, the lateral bending of thoracic-the lateral bending of lumbar, and the lateral bending of lumbar-the lateral bending of hip all displayed the coordinated kinematic coupling characteristics, which ensured spine to adjust the center of mass of the human body and maintain the stability of the human body in human gait motion.7. Based on the kinematic model of human motion and the experimental tracking marker system we had built and developed, we also carried out some exploratory experiments. Applying the kinematic model and the experimental tracking marker system, and building up the testing platform for multi-device synchronization integrated motion capture system, forceplate system, EMG system, Ultrasound system, and signal synchronization trigger, we had exploratorily carried out the experiment of ergonomic operation of sit posture as well as sit-stand human motion. The experiments showed that, it was feasible to study the biomechanics of local position of human body using the testing platform for multi-device synchronization, and it also verified the applied feasibility in other research fields using this kinematic model and the experimental tracking marker system.
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