一种防跌倒预警系统的研究与实现
The Study and Realization of an Early Pre-impact Fall Alarm System
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摘要: 跌倒是造成世界上意外伤害死亡的第二大原因, 如何预防跌倒已成为保障老人生命的关键。目前常见“跌倒报警器”的传感模块一般采用单一的三轴加速度计, 测量精度受限, 仅能实现人体跌倒后的报警功能而不能实现跌倒前的预警。文章设计并实现了一种基于 MEMS 惯性传感单元的防跌倒预警器, 率先设计了含“三轴加速度计+三轴陀螺仪+三轴磁力计”的高精度多模态传感模块, 内嵌跌倒预警算法, 并通过蜂鸣器和振动器警示。对九名健康年轻实验对象进行了总计 81 次的跌倒实验, 系统结合基于阈值的跌倒预警算法, 结果表明, 其检测灵敏度可达 98.61% 且特异度为 98.61%, 平均预警时间为 300 ms。未来研究将嵌入全球移动通信系统(GlobalSystem For Mobile, GSM)、全球定位系统(Global Positioning System, GPS)等电路模块功能及配备穿戴式安全气囊, 有望在易跌人群中实现实时防护和及时救治。Abstract: Falls are the second leading cause of unintentional injury deaths worldwide, so how to prevent falls has become a safety and security problem for elderly people. At present, because the sensing modules of most fall alarms generally only integrate the single 3-axis accelerometer, the measurement accuracy of sensing signals is limited. They can only achieve the alarm of post-fall detection but not the early pre-impact fall recognition in real fall applications. Therefore, an early preimpact fall alarm system based on high-precision inertial sensing units was studied and developed in this paper. A multimodality sensing module embedded with the fall detection algorithm was developed for the early pre-impact fall detection. The module included a 3-axis accelerometer, a 3-axis gyroscope and a 3-axis magnetometer, which could arouse early preimpact fall warnings by a buzzer and a vibrator. Total 81 times of fall experiments from 9 healthy subjects were conducted in simulated fall conditions. The result shows that the detection sensitivity of the system combining the early warning threshold algorithm can reach 98.61% with a specificity of 98.61%, and the average pre-impact lead time is 300 ms. In the future, GPS, GSM electronic modules and wearable protected airbags will be embedded in the system, which will enhance real-time fall protections and timely treatments for the elderly people.