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7 A Complementary Approach to Meeting PETMAN System Goals During the course of this study, the complexity of designing and con- structing a PETMAN system became evident. Therefore, feasible and com- plementary avenues involving existing technologies were discussed that could meet many of the requirements specified for PETMAN in a short period and at much lower cost. In this chapter, we discuss one such fea- sible approach that uses a sensor-integrated body suit under the soldier individual protection ensembles (IPE) that would provide substantial im- provements over current testing methods. This approach meets many of the PETMAN requirements, but does not provide for testing IPE in a live chemical agent environment. The current Man-in-Simulant Test (MIST) uses soldiers rather than mannequins; this offers the benefit of real human movements. Recreating human movement, respiration, perspiration, and body proportions in a robotic system is a difficult and expensive proposition. One of the failings of MIST is its method of leak detection. Participants are outfitted with pas- sive collection systems that provide a total exposure value with no spatial resolution to associate a leak with any particular movement and no periodic sampling for temporal analysis over the two-hour test duration. Another failing of the MIST is the inability to use an actual agent. However, if gases and vapors of equal molecular size and concentration diffuse and penetrate at equal rates, an appropriate simulant will diffuse through a breach in the suit and compromise its integrity in a manner similar to that of an actual agent. 129
130 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT The Sensor-integrated body suit As discussed in Chapter 5, smart textiles or wearable electronic sys- tems provide a possible platform for creating a real-time chemical sensing network. There are also sufficiently mature technologies, to construct a whole-body integrated-sensor suit outfitted with real-time sensing of chemi- cals, ambient and body temperature, humidity, and such vital signs as heart rate and electrocardiographic readings in a stand-alone or self-contained mode. The sensor-integrated body suit (SIBS) would meet the PETMAN re- quirements in Box 5-1 similar to the PETMAN soft skin (see Chapter 5), but would be worn by soldiers on the body and under the IPE. It could have a base fabric of typical textile materials used in military underclothing, such as MeraklonÂ® (staple polypropylene fiber), or cotton, polyester, and blends and could be made to be form-fitting with spandex (see Chapter 5). Opti- cal fibers can be integrated into the ensemble to take advantage of optical chemical-sensing technologies (see Chapter 3), which have demonstrated real-time detection of target chemicals that meets the optimal PETMAN concentration requirements. Although, it is likely that additional effort will be needed to develop the technology for this test application. Figure 7.1 is a diagrammatic representation of the form-fitting SIBS. The IPE to be tested would be worn by the soldier over the form-fitting body suit, thereby ensuring that no changes are made to the IPE for the purpose of testing. With the SIBS, all the key requirements denoted in Box 5.1 can be met except the use of real chemical agents during the testing. Thus, a sensor-integrated approach can provide a real-world test environ- ment and meet many of the PETMAN requirements. Advantages of the SIBS The proposed complementary approach will allow for a significant improvement in MIST without the expense and associated risk associated with a fully developed PETMAN at a small fraction of the costs in money and time. Using the SIBS will have the added advantage of real-time moni- toring of temperature and humidity and of the vital signs of the test subject. Testing would incorporate time-stamped video recording to correlate body movements and initial IPE locations with all measurements accurately. The SIBS would allow testing for all sizes of soldiers, not just the 50th percentile male measurements specified in Section 3.2.2 of the PETMAN requirements document. In addition, using actual soldiers will eliminate the â Service, R. F. 2003. News Focus Technology: Electronic Textiles Charge Ahead. Science, 301(5635):909-911; Park, S., and S. Jayaraman. 2003. Smart Textiles: Wearable Electronic Systems. MRS Bulletin (August 2003):585-591.
A COMPLEMENTARY APPROACH TO MEETING PETMAN SYSTEM GOALS 131 S1 Plastic Optical Fiber Sn Electrical Conducting Fiber Sensors Integrated into Skin Soft Skin Component Soft Skin Component Sensors of Different Types (Sn) Multifunction Controller Nega - Stat Figure 7.1 A form-fitting sensor-integrated body suit (SIBS) on a 50th percentile male. 7-1 cost and risk associated with robot development. Only a human moves like a human. The cost and technical difficulty of accurately mimicking human physiology are daunting. The proposed sensor-integrated approach would allow real-time monitoring and a huge variety of soldier movements and so provide added validation of suit integrity. This approach also eliminates the cost and potential hazards associated with the use of live agents. Disadvantages of the SIBS A potential drawback of this complementary approach is the inability to use live agents. If the test is designed to detect breaches in suit integrity, a live agent is not necessary. However, if the test is designed to assess the
132 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT Table 7.1 A Comparative Assessment of PETMAN and Complementary Approach PETMAN SIBS on Human Simulation of human Poor and expensive Excellent; minimal movement limitations Performance in extreme Minimal limitations Human-like limitations environments Use of actual agents Yes No Problems with actual agents Yes; decontamination Yes; cannot use; no required; potentially requirement for specialized high cost if mannequin facility is compromised Determination of breaches Yes Yes of IPE that result in chemical penetration Simulation of human Poor Excellent physiology Simulation of multiple Single size, 50th Available for all soldiers soldier sizes percentile male Standalone (self-contained) No Yes use behavior of an IPE in a live chemical environment, this requirement will not be met with the SIBS. Reproducibility and repeatability of defined motions are two key advantages of a robotic system. The SIBS would be worn by soldiers, and this might increase the acceptance of the test results in the soldier community, but the inherent variations introduced by human involvement could be another drawback of the proposed complementary solution. A comparative analysis of PETMAN and the proposed complementary approach of the SIBS is provided in Table 7.1. Conclusion The SIBS approach would meet a large majority of the objective test- ing requirements at a small fraction of the cost of PETMAN. If there is an absolute requirement for a PETMAN robot, the sensor-integrated approach could provide many of the key capabilities in the near term. This comple- mentary approach would offer substantial improvements over current test- ing methods while the critical paths for PETMAN development are being explored.