Detection Method And Equipment Implementation For Human Body Center Of Gravity

Balance function is a basic physiological function of human body, which is used as an effective balance guarantee for all kinds of activities in daily life, so the research on the body center of gravity will have a wide application value in the academic, medical and other fields. At present, the general method used to infer the balance ability in domestic and foreign is analyzing the sway of body gravity center under various postures. However, there are some obvious disadvantages in the common devices which used to measure body gravity center, the evaluation results were greatly influenced by subjective factors, some are bulky, expensive, and in inconvenient transportation. Based on the above issues, focusing on the balance ability evaluation as well as the human body gravity detection method, this study did the following work:Firstly, in order to detect the position of human bodies' gravity center in real time and evaluate balancing ability in each direction, this study constructed the two-dimensional gravity detection and balance evaluation system based on the structure of single inverted pendulum model, which took PC/104 as the core controller, and QNX was adopted as real-time operating system. A force platform was used to acquire the information of COP(center of pressure) and regulation time was used as balance indicator. The evaluation software with visual stimulus was designed to provide random visual excitation source in multi-directions, avoiding the errors caused by subjects' preparation of motion directions.Secondly, feasibility of the given method was validated through the experimental study of 73 healthy undergraduate students, proving that the method can assess the balance of multi-directions objectively, and reference range(4-13 s) of healthy persons' regulation time were obtained as well; In addition, the experimental results reflected there were correlations between human gender, height and balance ability, but the relationship between weight and balance ability was not obvious in a certain extent.Thirdly, owing to the problems and shortcomings found in the experiment process of 2D gravity detection system, a three-dimensional detecting method was proposed. Body balance process was realized by the rotation of each joint, and the balance process could be detected by using the angle sensor network which was installed in each joint. The 3D-Coordinate formula of human gravity center during vertical state was deduced by using the synthesis method and coordinate transformation, and the portable dynamic measurement system based on angle sensors was constructed according to this principle.Fourthly, the study adopted the contrast experiment method to validate the feasibility of three-dimensional-gravity-center measurement system, and the motion capture system was used as reference group. 20 healthy college students had taken part in the experiment. Synthesizing the analysis results in distribution of trajectories, the maximum value and minimum value and the root-mean-square errors of two groups' gravity center in three-dimensional direction, it showed that the gravity center data obtained by the two systems had high consistency, which confirmed the feasibility of tilt angle system.This research proposed the detection method of 3D gravity center based on the two-dimensional detection system, and completed the system construction. The characteristic of this system was introducing the tilt sensor network, and the inclination angle of each composition segment can be measured in real-time. The three-dimensional coordinates of gravity center will be obtained by substituting angles into the formula, which was convenient and had less calculation.