Design and Realization of a Wearable Hip-Airbag System for Fall Protection

Abstract:

Nowadays falls are a serious problem for elderly people with the coming of aged society in the world. According to statistics,hip fracture accounts for the most of the deaths and costs of all the fall-induced injury. This paper presented an airbag system of hip protection, which included air source, sensors, microcontroller, gas circuit and airbags. A six-axial inertial sensor module that integrated an embedded three-axis MEMS accelerometer and three-axis MEMS gyroscope was used to collect human motion data, and a one-axis obliquity sensor was used to collect human angle data. The microcontroller was employed to recognize the activities of daily living (ADL) and falls based on fall detection algorithm and the collected data from sensors. The gas circuit was triggered once the event that the fall would be inevitable was confirmed by the microcontroller, then the compressed gas would fill into airbags through the gas circuit rapidly. Therefore, a buffer would appear between the human body and the ground before the body impacting the ground, which would reduce the impact of the human body. Compressed CO₂ was selected as the air source after we tested several kinds of gas. A 16g CO₂ pressurized cylinder could provide enough pressure and volume to inflate quickly the airbags. In order to improve the reliability of the gas circuit, a needle valve was optimized from the several designed structures by the experimental optimization methods. Finally, the airbag system was tested in various designed trials. The results indicated that the system gained the satisfaction for the design requirements and would be potential to apply to the protection of hip joint in the fall high-risk people in the future.

• Periodical: Applied Mechanics and Materials (Volume 461)
• Pages: 667-674
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.461.667
• Online since: November 2013
• Authors: Qi Zhang, Hui Qi Li, Yun Kun Ning, Ding Liang, Guo Ru Zhao
• Keywords: Airbag, Fall, Hip Protection, Inertial Sensor

References

[1] World Health Organization (WHO), Falls, Available online: http: /www. who. int/mediacentre/ factsheets/fs344/en /index. html.

[2] J. Parkkari, P. Kannus, M. Palvanen, et al, Majority of hip fractures occuras a result of a fall and impact on the greater trochanter of the femur: a prospective controlled hip fracture study with 206 consecutive patients, Calcif Tissue. 65 (1999).

DOI: 10.1007/s002239900679

[3] S.R. Cummings, M.C. Nevitt, A hypothesis: the causes of hip fractures, J Gerontol. 44 (1989) 107– 111.

[4] F.J. Imms, O.G. Edholm, Studies of gait and mobility in the elderly, Age Ageing. 10 (1981) 147–156.

DOI: 10.1093/ageing/10.3.147

[5] M. Parker, A. Johansen, Hip fracture, British Medical Journal. 333 (2006) 27–30.

[6] M.J. Park, J.W. Myles, J.K. Anand, R. Drewett, Cost-Benefit analysis of hip fracture treatment, The Journal of Bone and Joint Surgery. British Volume 74 (1992) 261–264.

DOI: 10.1302/0301-620x.74b2.1544965

[7] G. Salkeld, I.D. Cameron, R.G. Cumming, S. Easter, J. Seymour, S.E. Kurrle, S. Quine, Quality of life related to fear of falling and hip fracture in older women: a time trade off study, British Medical Journal. 320 (2000) 241–246.

DOI: 10.1136/bmj.320.7231.341

[8] O. Johnell, J. Kanis, Epidemiology of osteoporotic fractures, Osteoporos. 16 (2005) 3–7.

[9] T. Tamura,T. Yoshimura, M. Sekine, M. Uchida, O. Tamura, A wearable airbag to prevent fall injuries, IEEE Transactions on Information Technology in Biomedicine. 13 (2009) 910–914.

DOI: 10.1109/titb.2009.2033673

[10] G.Y. Shi, S.C. Cheung, G.L. Zhang, et al., Towards a mobile airbag system using MEMS sensor and embedded intelligence, In Proceedings of IEEE International Conference on Robotics and Biomimetics, Sanya, 2007, pp.634-639.

DOI: 10.1109/robio.2007.4522236

[11] M. Kangas, A. Konttila, P. Lindgren, I. Winblad, T. Jämsä, Comparison of low-complexity fall detection algorithms for body attached accelerometers, Gait Posture. 28 (2008) 285–291.

DOI: 10.1016/j.gaitpost.2008.01.003

[12] C. Lin, H. Hus, Y. Lay, C. Chiu, C. Chao, Wearable device for real-time monitoring of human falls, Measurement. 40(2007) 831–840.

DOI: 10.1016/j.measurement.2007.04.001

[13] G.R. Zhao, Z.Y. Mei, D. Liang, KamenIvanov, Y.W. Guo, Y.F. Wang and L. Wang, Exploration and Implementation of a Pre-Impact Fall Recognition Method Based on an Inertial Body Sensor Network. Sensors, 11 (2012) 15338-15355.

DOI: 10.3390/s121115338

[14] D. Liang, G.R. Zhao, Y.W. Guo, L. Wang, Pre-impact & impact detection of falls using wireless body sensor network, In Proceedings of the IEEE-EMBS International Conference on Biomedical and Health Informatics, Shenzhen, 2012, p.763–766.

DOI: 10.1109/bhi.2012.6211695