Design Of Motion Capture System And Its Application Based On Wireless MEMS Sensors

The care and monitoring of aged people had become increasingly significant with the growing aged population in China. The fall of the old people would cause serious complication to them, which seriously affect the quality of their life with the increased medical, rehabilitation cost. Meanwhile, for those patients who were in physical rehabilitation, the quantization of motion and acquisition of these quantized parameters were of significance to the diagnose of clinical doctors. These quantized parameters could be used to indicate and estimate health state of patients, such as the recovery of limb function, rehabilitation progress, balance ability and the risk of fall. Although there were many existing techniques to evaluate and monitoring human activity, such as computer vision based motion tracking system, optics based motion analysis system or even acoustic system to detect falling, there were some disadvantages over the above techniques, such as high cost, complex computation; lack of portability and above all, most of these techniques were designed for in-laboratory measurement.Nevertheless, recent advance in Micro-Electro-Mechanical Systems (MEMS) had made the inertial sensors smaller and cheaper with high sensitivity and SNR while low power and cost could also be achieved. None-obstructive and wearable accessories incorporating these inertial sensors which could be attached to human body for long period of time had become available. Moreover, low power wireless data communication technique also enhanced them for portability. By comparison with the imaging base remote diagnosis system, body sensor networks had no transmitting band width limit because of their small size data.The research was conducted in the object of obtaining motion information. A wireless sensor node that integrated accelerometers, gyroscopes, magnetometers controlled by TI's low power MCU MSP430 was designed. Meanwhile a base stationwhich performed the task of receiving wireless signal was designed also mainly onMSP430 platform. The base station transmitted the data to PC via RS232 protocol for more advanced data processing, such as motion reconstruction. The data communication software written by VS2005 would decode the data package and plot the signal. For lost package during the wireless transmission, the software would send lost package re-sending request to the base station by the design protocol, which might facilitate data analysis after the real-time data transmission.