Manipulator Based Back-shu Points' Impedance Detection System

The meridian theory is an important component of the traditional Chinese Medicine, which has contributed a lot to the health and development of Chinese natron. Acupoints are located along the meridian, where Qi-blood of human body comes in and out. Among them, Back-shu points lie along the circulation route of The Bladder Meridian of Foot-Taiyang, corresponding to the position of Zang-Fu organs. The Back-shu points are widely used to diagnose Zang-Fu diseases. The Human Body Impedance Detecting System has been designed, which consists of the manipulator for data acquisition and the PC diagnosis platform. The system aims to analyze the relationship between human body impedance and diseases, through detecting the characteristics of the impedance, and to provide objective data for medical diagnosis. This thesis is divided into three parts.Part one: impedance acquisition design. The light projector helps to locate the Back-shu points, and then moves the detecting electrode automatically along the Back-shu points, from Feishu to Pangguangshu, recording the human body impedance at the same time.Part two: system design. The manipulator platform is built with three mutually perpendicular arms, the corresponding control system, PC and the detecting electrode, in order to assure the stability of velocity and pressure while capturing data. The system enables us to design and debug EasySMC control, step motor and its driver, data acquisition equipment, etc. Programs of serial port communication are written to fulfill these functions: the movement control of manipulator and PID control of electrode pressure detection. The human body impedance data is recorded through the LineIn port of the PC.Part three: data processing and analysis. The process includes denoising the audio impedance data by mean filter, and extracting the envelop of audio impedance data by Hilbert-Transform, extremum method and digital low-pass filter. Then the real human body impedance is calculated through transformation. The impedance of Back-shu points is detected for multiple times continuously, to validate the usability of the system. The experiment indicates that the frequency of sinusoidal signal influences the impedance a lot. When the frequency grows, the impedance will make a nonlinear decrease. The change of pressure within a range has very little influence on impedance. At present, the system has been applied to clinical experiment in Hangzhou Chinese Medicine Hospital. The characteristics of impedance need further study to identify its relationship with diseases, which has already shown a bright future in application.