An Airbag System For Fall Protection Based On Inertial Sensors

With China entering the phase of demographic aging, physical health of the elderlyhas become a major factor that affecting social development. According to HealthMinistry statistics, the fall has become the fourth largest cause of injuries amongresidents of mortality. And with the age increasing, the mortality increasing sharplyrise in older age. The fall could make a direct result of death seriously in the elder, thelight could also lead to physical disability, and also affect their mental health.Therefore, research and development an airbag system to protect the hip of the bodyis necessary.1. I studied the existing algorithm of fall detection, and determined to use theinertial sensors to design the airbag system for fall protection. Then I studied theinertial sensors, and determined the algorithm of fall detection about this system.2. Used of a commercial inertial sensor components Xsens to make a fallexperimental design, which respectively collected human right leg, right leg, waistand chest four parts data, eight different actions data, and then processed and analysisthe data that used Matlab. I find the best body wear part of the inertial sensor is thewaist, and find out that parameters can distinguish between the fall and the humanbody normal action is the synthetic acceleration and the synthetic angular velocityand attitude Angle of the human body. Finally determined the threshold of syntheticacceleration is5m/s/s, the threshold of synthetic angular velocity is30°/s, and thebody’s Angle threshold is20deg.3. This system used the inertial sensor chip MPU9150, which integrated three-axisaccelerometer, three-axis gyroscope and three-axis magnetometer, to collect the dataof human activity; Used MSP430F2418PM single-chip microcomputer as the mastercontrol chip of a data processing and servo drive; Used TR213steering gear forinflatable balloon. Used the Altium Designer to design and drawing the hardwarecircuit diagram and PCB of this system, and used the IAR software to design theprogram of the single-chip microcomputer.4. We set up and tested the system after the design was completing. Firstly we testevery module the system, to ensure the normal work of the every module. After, weused a dummy to make fall experiments to prove the feasibility of fall protection airbag system.5. I summarized this system, and looked forward to the future development of thewearable air system based on inertial sensors, which protect the hip from fall.