2
Design Challenge: Simulation of Human Physiology

This chapter addresses the simulation of temperature, perspiration, and respiration, described in PETMAN design challenge 3.2.5 (see Appendix B):


The study will determine the feasibility of designing a PETMAN system that can simulate fixed skin temperature (by body region), perspiration rate (by body region), and respiration rate (threshold level) and a realistic variability in skin temperature, perspiration rates, and respiration rates based on the amount of physical activity/exertion (objective level) defined in 3.3.4.1-3.3.4.3.


This chapter includes a discussion of the relevant PETMAN requirements (Box 2.1), current technologic capabilities, design challenges and how they might be addressed with current and future technology, costs and benefits of different approaches, and feasibility and potential trade-offs.

CURRENT TECHNOLOGIC CAPABILITIES

The human-physiology simulation aspects of the PETMAN system may be best categorized as follows: temperature and perspiration, respiration and ventilation, and physiology integration. Each of those functions has been simulated to some degree by currently available systems; a few systems incorporate all three. We reviewed all currently available systems that can simulate at least one, and we include here information on technical specifications, images, and references.



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2 Design Challenge: Simulation of Human Physiology This chapter addresses the simulation of temperature, perspiration, and respiration, described in PETMAN design challenge 3.2.5 (see Appendix B): The study will determine the feasibility of designing a PETMAN system that can simulate fixed skin temperature (by body region), perspiration rate (by body region), and respiration rate (threshold level) and a realistic variability in skin temperature, perspiration rates, and respiration rates based on the amount of physical activity/exertion (objective level) defined in ...-.... This chapter includes a discussion of the relevant PETMAN require- ments (Box 2.1), current technologic capabilities, design challenges and how they might be addressed with current and future technology, costs and benefits of different approaches, and feasibility and potential trade-offs. CuRRENT TECHNOLOgIC CAPAbILITIES The human-physiology simulation aspects of the PETMAN system may be best categorized as follows: temperature and perspiration, respira- tion and ventilation, and physiology integration. Each of those functions has been simulated to some degree by currently available systems; a few systems incorporate all three. We reviewed all currently available systems that can simulate at least one, and we include here information on technical specifications, images, and references. 

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT Box 2.1 Relevant PETMAN Requirements The requirements below outline the desired level of simulating human physiol- ogy in the PETMAN system excerpted from the detailed list of PETMAN system design requirements that appear in Appendix B: 3.3.3 The PETMAN system shall meet the anthropometric requirements of the 50th percentile male in accordance with DOD-HDBK-743A, Military Handbook Anthropometry of U.S. Military Personnel, 13 February 1991. 3.3.4 The PETMAN system shall simulate the following environmental/physiologi- cal conditions under the individual protection ensemble. 3.3.4.1 The PETMAN system shall simulate fixed skin temperature by body re- gion (T) and more realistic variability in body surface temperature based on body region and the level of physical activity/exertion (O). 3.3.4.2 The PETMAN system shall simulate a fixed perspiration rate of 0.4 L/hr (T) and more realistic variability in perspiration rates (range 0.11 to 1.8 L/hr) based on the level of physical activity/exertion (O). 3.3.4.3 The PETMAN system shall simulate a respiration rate of 50 L/min (fixed tidal volume of 1.5 L & breath frequency of 33 breaths/min) (T) and more realistic variability in respiration rates (range 10 to 115 L/min with variable tidal volumes and breath frequencies) based on the level of physical activity/exertion (O). 3.3.13 The PETMAN system shall record the following system parameters over time: skin temperature, respiration rate, perspiration rate, and total mass (in nanograms) of chemical vapor that penetrates/permeates through the protective ensemble. The PETMAN system shall record the start and stop time of each mo- tion in 1 second increments. NOTE: T=threshold (minimum requirement) and O=objective Temperature and Perspiration Several generations of thermal mannequins have been developed in the last 70 years for various commercial and military purposes. Used pri- marily for garment evaluation, early versions manufactured in the 1940s through 1960s were standing, mostly nonarticulated and nonperspiring models. Second-generation variants with movable body parts and append- ages started to appear in the 1970s. The addition of perspiration capability has been more recent in what may be considered third-generation and later

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY thermal mannequins. Several documents reviewing those types of man- nequins (also referred to as manikins) and their evolutionary changes are available.1 Military Systems Information on and specifications of several mannequins constructed by the armed forces of several nations and put into service for assessment of battle dress uniforms, protective ensembles, and other combat-related cloth- ing and equipment are publicly accessible. Two military systems with the most detailed available information are the Uncle Wiggly and Paul manne- quin systems, both housed at U.S. Army facilities. Information on similarly functional U.K. and Canadian systems are discussed in Chapter 1. uncle Wiggly: Based at the U.S. Army Research Institute of Environmental Medicine (USARIEM) in Natick, Massachusetts, Uncle Wiggly was origi- nally developed in 1984 with a copper-plated shell, cast-aluminum joints, and assorted heaters and sensors (Figure 2.1). Measurement Technology Northwest (in Seattle, Washington) updated the mannequin in 2004 with a thermal-control system consisting of signal conditioning, heater drivers and computer software, and a computer-controlled sweating system. Uncle Wiggly features 19 individual heating zones, each with its own replaceable plug-and-play microcontroller to oversee temperature and fluid control and measurement. Software controls provide automatic steady- state detection; the operator can also program a work-cycle simulation and view instantaneous bar graphs and time-line graphs of any variable. Data updates are shown every second with calculations for number of watts of heat removed. Sweating occurs automatically through a series of valves and hoses that pump water through dozens of “weep holes” drilled through the metal that allow even and adjustable water distribution along the 19 sections. Motion capability includes the ability to swing arms and legs to simulate walking at speeds up to 3 mph. Testing is conducted in its own chamber that is controlled for temperature, humidity, and wind speed provided by a fan. Paul: Paul (Figure 2.2) is a nonthermal, animatronic mannequin at the U.S. Army Soldier and Biological Chemical Command (SBCCOM) in Natick, 1 Holmér, I. 2004. Thermal Manikin History and Applications. European Journal of Applied Physiology 92(6):614-618; Holmér, I., and H. Nilsson.1995. Heated Manikins as a Tool for Evaluating Clothing. Ann. Occup. Hyg., Oxford University Press 39(6):809-818; Endrusick, T. L., L. A. Stroschein, and R. R. Gonzalez. Thermal Manikin History: United States Military Use of Thermal Manikins in Protective Clothing Research. Measurement Technology Northwest, http://www.mtnw-usa.com/thermalsystems/history.html. Accessed August 9, 2007.

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT FIguRE 2.1 U.S. Army Research Institute of Environmental Medicine’s (USARIEM’s) Uncle Wiggly thermal mannequin in its own climate-controlled test chamber for measuring thermal and vapor resistance values of clothing ensembles. SOURCE: “Modernized manikin: Uncle Wiggly resumes thermal testing after major ‘organ’ replacement.” The Warrior, March-April 2004. http://www.natick.army. 2-1 mil/about/pao/pubs/warrior/0/marapr/index.htm. Accessed August 7, 2007. Massachusetts, but has been used for testing protective garments in a MIST chamber.2 Built in 2002 by Creative Engineering, Inc. (in Orlando, Florida). Paul can be programmed for at least 20 motions. Nonmilitary Systems Commercial and academic groups have expended considerable time, effort, and expense to developing increasingly sophisticated and specialized thermal mannequins.3 Some of the more prominent and innovative manne- 2 U.S. Army Soldier Systems Center, Vapor Chamber Tests Chem/Bio Protective Prototypes. http://www.amc.army.mil/amc/pa/Aug0Issue.html. Accessed June 13, 2007. 3 Nilsson, H. O. (2004). Comfort Climate Evaluation with Thermal Manikin Methods and Computer Simulation Models. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-. Ac- cessed August 8, 2007.

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY FIguRE 2.2 U.S. Army Soldier and Biological Chemical Command’s Paul manne- quin cycling through motions in the Man-in-Simulant Test chamber. SOURCE: “Vapor chamber tests chem/bio protective prototypes” (photo by Curt Biberdorf), http://www.amc.army.mil/amc/pa/Aug0Issue.html. Accessed August 7, 2007. 2-2 quin models are reviewed below. These are loosely categorized into “nonin- tegrated” systems that use discrete simulations of physiologic functions and “integrated” systems that are driven by human-physiology models. Nonintegrated Systems These systems use discrete simulations of physiologic functions. Coppelius and variants: This line of mannequins originated in the VTT Technical Research Centre of Finland Laboratory of Plastics and Fiber Technology. Coppelius (Figure 2.3) features prosthetic joints for externally induced movement and different postures and computer-controlled heating

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0 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT FIguRE 2.3 Coppelius mannequin. SOURCE: Used with permission of North Carolina State University. and sweating systems, with 18 individually controlled body sections and 187 sweating glands (distributed over the whole body except the head, hands, and feet). A Coppelius type of mannequin has been developed at the Center for Research on Textile 2-3 Protection and Comfort of North Caro- lina State University through technology exchange with the Finnish VTT group.4 TOM III and SAM: Toyobo Corporation of Japan has manufactured two types of thermal sweating mannequins, TOM III (1980s) and SAM (1990s). They are differentiated primarily by their sweating mechanisms. TOM III uses water vapor from 220,000 “pores,” whereas SAM sweats liquid water intermittently from 168 sites. SAM measures a broader array of variables (heat dissipation, “skin” temperature, and so on, in addition to temperature and humidity under clothing) and has more sophisticated computer control than TOM III. 4 Additional information is available at http://www.tx.ncsu.edu/tpacc/comfort/sweating_ manikin.html.

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY Walter: A team at the Institute of Textiles and Clothing of Hong Kong Polytechnic University, in Kowloon, Hong Kong, is using fabric technolo- gies for its thermal sweating mannequin Walter (Figure 2.4). A waterproof but moisture-permeable fabric “skin” covers 1.5 m2 of surface area and simulates the evaporation of sweat by moisture transfer of internally circu- lated body-temperature water from the mannequin core through tiny pores. The “skin” can be unzipped and interchanged with different versions to simulate different rates of perspiration. Newton and Huey: Measurement Technology Northwest (MTNW), in Se- attle, Washington, which developed the most recent version of USARIEM’s Uncle Wiggly system, also produces several commercial systems for simu- lation of human physiologic temperatures and sweating. Its Newton and Huey models are constructed of aluminum-filled fiberglass-epoxy and alu- minum, respectively; articulated joints and external frame allow for move- ment. Customizable and independent thermal zones—14-45 for Newton Front view Side view FIguRE 2.4 Sweating mannequin Walter. SOURCE: Fan, J., Y. Chen, and W. Zhang. “A Perspiring Fabric Thermal Manikin: Its Development and Use.” Proceedings of the Fourth International Meeting on Thermal Manikins, EMPA Switzerland, Sept. 27-28, 2001. 2-4

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT and up to 30 for Huey—can be used with an optional removable fabric sweating skin with an output capacity of 50-1,000 mL/h-m2. JuN: Built at Bunka Women’s University, in Tokyo, with assistance from the Japan Society for the Promotion of Science, JUN incorporates several of the capabilities and features of previously discussed mannequin systems, namely, independently controlled and zoned thermal and sweating systems, fabric “skin,” and externally inducible movement. Separation of the core and a 17-segment external shell allows distinct simulation of core and sur- face temperatures. Integrated Systems Integrated systems are driven by human-physiology models. Advanced Automotive Manikin (ADAM): Actively used for research at the National Renewable Energy Laboratory (NREL), ADAM is another mannequin assembled by MTNW (Figure 2.5).5 Measuring 61 kg and 175 cm and designed primarily as an automobile occupant, ADAM has 126 individually controlled stand-alone surface zones, each with a surface area of 120 cm2 and integrated heating, temperature-sensing, sweat distribution and dispensing, and a heat-flux gauge and a local controller to manage closed-loop operation. Zone skin temperature is determined by an array of thermistors, and the sweating surface is all metal and optimized for thermal uniformity and response speed. Novel features include wireless control, a 24-V battery pack for two hours of autonomous continued operation, and a respiratory-simulation system for physiologic ventilation and heating with humidification of ambient air at up to 8 L/min. The most unusual aspect of ADAM is its numeric physiologic model.6,7 As temperatures are manipulated in ADAM’s environment, the resulting skin heat-transfer rates are reported to a physiologic computer that uses mannequin conditions to generate prescribed and appropriate skin tempera- tures, surface sweat rates, and breathing rates. A loop feedback provides ever-changing measurements for assessment of human thermal comfort in 5 Advanced Thermal Manikin. Measurement Technology Northwest. http://www.mtnw-usa. com/pdf/ADAM.manikin.specs.pdf. 6 Paul, H., L. Trevino, G. Bue, J. Rugh, R. Farrington, and C. King. Phase II Testing of Liquid Cooling Garments Using a Sweating Manikin, Controlled by a Human Physiological Model. Doc 2006-01-2239. SAE International. 7 Farrington, R., J. Rugh, D. Bharathan, H. Paul, G. Bue, and L. Trevino. Using a Sweating Manikin, Controlled by a Human Physiological Model, to Evaluate Liquid Cooling Garments. Doc 2005-01-2971. SAE International.

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY FIguRE 2.5 ADAM, the advanced thermal manikin. SOURCE: Burke, R., and R. McGuffin, “Development of an Advanced Thermal Manikin for Vehicle Climate Evaluation” Proceedings of the Fourth International Meeting on Thermal Manikins, EMPA Switzerland, Sept. 27-28, 2001; R. Burke, Measurement Technology NW. 2-5 a dynamic environment. A separate thermal-comfort model predicts human perceptions of comfort under environmental conditions. Sweating Agile Thermal Manikin (SAM): The Swiss Federal Laboratories for Materials Testing and Research (St. Gallen, Switzerland) has developed SAM, which is equipped with 26 shell parts and 4 heated joints in 30 sepa-

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT rately heated sectors constructed of plastic mixed with aluminum powder (Figure 2.6). Electronics and software enable each sector to be heated to a constant temperature or with constant power using just one power supply for all shell parts. The maximal total heating power is 1.2 kW, the equiva- lent of very high-level human muscular activity. One hundred twenty-five sweat outlets are distributed over the man- nequin surface and positioned to ensure roughly human sweat distribution. Special pads cover the outlets to ensure that all water evaporates at low FIguRE 2.6 Sweating Agile Thermal Manikin (SAM). SOURCE: SAM Sweating Agile Thermal Manikin of EMPA, Switzerland.

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY sweat rates to simulate insensible sweating or as both vapor and liquid water at higher sweat rates to simulate sensible sweating. Total sweat rate is controlled with a precision balance to measure the reduction in supply- tank water outside SAM; total moisture within clothing is determined by monitoring SAM’s weight. The sweat rate can be varied from 20 mL/h to at least 4 L/h. Heating power, sweat rate, and body movements are linked for active-exercise phases to simulate human activities. Joints at the shoulders, elbows, hips, and knees enable each limb to be moved in a vertical plane. Each limb is connected to a two-axis linear drive mechanism with movement curves defined as series of points with spline interpolation to ensure smooth curving, acceleration, and deceleration. Re- petitive body movements, such as walking and climbing, can be performed during active testing by using a specially developed supporting frame. SAM is positioned in an environmental chamber that can be operated at tempera- tures of –30°C to 40°C and relative humidity of 30-95 percent. High wind speeds can be simulated by a wind generator positioned in front of SAM. The control unit is positioned on a trolley outside the chamber; heating and sweating supplies are connected through the face. Other Temperature- and Perspiration-Related Systems Several mannequin systems with environmental characteristics and ca- pabilities not covered by the PETMAN specifications are also available. The PyroMan Thermal Protective Clothing Analysis System is an adult- size flame-resistant mannequin system with 122 heat sensors distributed uniformly over the body (excluding hands and feet).8 Each of PyroMan’s sensors covers 0.82 percent of body area and is individually calibrated to ensure accurate reading of temperature and calculation of surface heat flux. The temperature readings, in conjunction with a one-dimensional transient heat-conduction model, are used to determine the heat flux experienced at the sensor’s surface as a function of time. A liquid-integrity testing system has also been described. A liquid-ab- sorbing inner garment is placed over a mannequin and underneath the gar- ment being tested to show penetration by test liquid. Water is the principal challenge agent; it is often treated with a surfactant to increase test severity. The testing duration is usually extended so that clothing design problems or defects will show up more readily. Test results are reported as pass or 8 Barker, R. L. A Review of Gaps and Limitations in Test Methods for First Responder Protective Clothing and Equipment. January 31, 2005. Prepared for the National Insti- tute for Occupational Safety and Health available at http://www.cdc.gov/niosh/npptl/pdfs/ ProtClothEquipReview.pdf. Last accessed August 7, 2007.

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT On the basis of the extensive physical-activity requirements speci- fied for PETMAN, the onboard processing and robotic actuation (whether pneumatic, electric, or hydraulic) involved will require substantial energy stores and generate considerable heat and exhaust. Although a breathing- mannequin system at rest could potentially be made to thermoregulate and perspire appropriately in all its body segments, the technology to control mannequin heating and cooling dynamically to achieve the same homeo- stasis within the limits of operational testing is not now available. COST-bENEFIT ANALySIS AND TRADE-OFFS The PETMAN requirements related to human physiology are analyzed in Table 2.1. The analysis includes discussion of the technical benefit, cost impact (disadvantages), near-term availability, and feasibility. FEASIbILITy AND POTENTIAL ALTERNATIvES Based on the information presented earlier in this chapter, it is feasible to simulate the independent components of physiologic conditions under the IPE (requirement 3.3.4, Appendix B) at least the threshold levels. However, given the space available in the mannequin (50th percentile male anthropometrics) and the heating, cooling, and sweating system require- ments (power, supply, and exhaust demands), it is not feasible with current technologies to meet the human physiologic requirements with additional chemical sensing and robotics operational requirements in an autonomous nontethered PETMAN system. Conclusion 2-1a: Simulation of chest-wall movement associated with respiration is feasible. Conclusion 2-1b: Simulation of human respiration and ventilation with chest movement and respiratory tract airflow through external (tether- connected) pneumatics is feasible. Conclusion 2-1c: Internalization of all systems necessary to generate chest-wall movements and simulated respiration and ventilation in the mannequin will require additional research and development. Recommendation 2-1: The role of simulated respiratory tract airflow in the mannequin during IPE testing should be further clarified. Distinct from simulation of respiratory chest-wall movement for re-creation of under-ensemble airflow, the generation of accurate mannequin inspira- tory and expiratory airflow through a mask respirator will require ad-

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY ditional development and may duplicate current protocols for testing of IPE mask respirators in isolation. Conclusion 2-2a: Simulation of human activity-dependent skin tem- peratures and sweating (with water as a sweat equivalent) should be feasible when space, power, electric, and exhaust requirements of other PETMAN subsystems are housed outside the mannequin via a tether. Conclusion 2-2b: Integration of activity-dependent human-like skin temperatures and sweating into mannequin wide thermoregulation with differential heating and cooling through a circulatory system has not been achieved. That is, a static mannequin can be warmed and made to sweat appropriately, but no commercially available system has the capacity to cool a moving robot’s actuator systems and onboard computers while heating its surface “skin.” However, based on the currently available systems, this requirement may be feasible with ad- ditional short-term research and development. Recommendation 2-2: Inasmuch as mannequin-wide thermoregulation is by definition an all-or-none proposition, its feasibility analysis does not lead to recommendations regarding potential alternatives or sacri- fices in performance requirements. Conclusion 2-3a: Mannequin respiration, skin temperature, and sweat- ing should be controlled through either preset physiologic characteristics for defined IPE test activity states or a mannequin metabolism model designed to operate without physiologic linkage to sensor systems. Conclusion 2-3b: Integration and installation of the necessary sys- tems to achieve all human-physiology simulation requirements into a PETMAN that meets all specified operational requirements will en- counter substantial challenges with the use of technologies that are currently available or are expected to be available in the near future. The presence of a tether may relieve some—not all—obstacles to this objective. Recommendation 2-3: A phased development project with progression through transitional stages may alleviate several technologic hurdles that need to be overcome if all human-physiology simulation require- ments are to be met in a robotic sensing PETMAN. The above conclusions are in accordance with the feasibility analyses of other PETMAN system considerations, such as robotics (see Chapter 4) and systems integration (see Chapter 6).

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT TAbLE 2.2 Cost-Benefit Analysis of Simulating Human Physiologic Characteristics as Part of PETMAN System Requirement Requirement Number Description Technical Benefit 3.3.1 Tethered (T) Easier, cheaper solution to power, thermal, mechanical issues Untethered (O) No modification of IPE; potentially more realistic test challenge 3.3.3 Anthropometric Compatibility with protective requirements of 50th ensemble percentile male 3.3.4.1 Fixed skin-temperature Intended to be easier to simulation by body achieve than variable region (T) temperature based on region and activity

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY Cost Impact/ Near-term Feasibilitya Disadvantages Comments Availability Requires Assume not just Would still 3 nonstandard a simple tether: require modification of IPE mechanical, power, integrating coolant interface subsystems but appears feasible in 1-2 years Power, thermal, — — 1 mechanical challenges; probably insurmountable in required timeframe Space limitations — — 1 leading to restrictions on every system Maintaining skin Not much easier Heating 3 at controlled than variable subsystems temperature, skin temperature; are available whether fixed challenge is in from several or model-based, system integration mannequin requires both manufacturers; heating and cooling cooling regulation methods could be adapted from spacesuit technology continued

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0 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT TAbLE 2.1 Continued Requirement Requirement Number Description Technical Benefit Variable skin-temperature More accurate simulation simulation by body region of temperature in IPE, and level of physical activity hence realistic simulation or exertion (O) of IPE internal and external environmental challenges 3.3.4.2 Fixed perspiration rate (T) Intended to be easier or cheaper to achieve than variable perspiration rate Variability in perspiration Accurate simulation of rate based on level of moisture environment in IPE, physical activity or exertion capturing moisture effect on (O) agent behavior 3.3.4.3 Fixed respiration rate: (a) Small increase in accuracy of combined simulation of agent transport in IPE and in IPE mask

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY Cost Impact/ Near-term Feasibilitya Disadvantages Comments Availability Maintaining skin Not much more Heating 3 at controlled difficult than fixed subsystem temperature, skin temperature; are available whether fixed challenge is in from several or model-based, system integration mannequin requires both manufacturers; heating and cooling cooling regulation methods could be adapted from spacesuit technology Complex Not much Subsystems 3 liquid-delivery less difficult are available system available than variable from several from several perspiration rate; mannequin manufacturers challenge is in manufacturers system integration — Not much more Subsystems 3 difficult than fixed are available perspiration rate; from several challenge is in mannequin system integration manufacturers Pneumatic or Current Potentially 3 actuated system mannequin applicable that simulates systems use subsystem also chest motion while positive pressure, available from driving respiratory unlike humans respiratory- flow mask testing companies continued

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT TAbLE 2.1 Continued Requirement Requirement Number Description Technical Benefit Fixed respiration rate: (b) Accuracy of simulation of respiratory flow only agent transport in IPE mask Fixed respiration rate: (c) Accuracy of simulation of chest motion only agent transport in IPE, that is, under-ensemble Variable respiration rate Additional small increase in based on level of physical accuracy of simulation of activity or exertion (O) agent transport in IPE and in IPE mask 3.3.11 Decontaminate with no Necessary to process multiple effect on next iteration tests of test (T) Decontaminate leaving — negligible agent residual defined by DA PAM 385-61 (O)

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY Cost Impact/ Near-term Feasibilitya Disadvantages Comments Availability Pneumatic or Positive or Potentially 2 actuated system negative pressure applicable that drives not specified in subsystem also respiratory flow requirements available from respiratory- mask testing companies Pneumatic or May be Used by 1 actuated system insignificant some current that simulates chest compared with mannequins motion limb-motion effects Preprogrammed — Potentially 1 control, variable- applicable speed motor subsystem also available from respiratory- mask testing companies Will probably — — 1 require time, effort, resources between tests Agent residue may — — 1 complicate some sensor readings continued

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 SOLDIER PROTECTIVE CLOTHING AND EQUIPMENT TAbLE 2.1 Continued Requirement Requirement Number Description Technical Benefit 3.3.13 System measure recording Test-data logging for analysis Nonrequirement issues: Physiologic integration Necessary for all requirements System integration to be met simultaneously Accurate modeling of skin, — anatomy to represent mask seals Packaging — Cooling — a3 = high feasibility, 2 = medium feasibility (achievable with substantial effort), 1 = low feasibility (extremely difficult to achieve)

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 DESIGN CHALLENGE: SIMULATION OF HUMAN PHYSIOLOGY Cost Impact/ Near-term Feasibilitya Disadvantages Comments Availability Additional — Available 3 power, storage from several requirements mannequin manufacturers — Significant design — 1 and development risk—combined robotic-physiologic mannequins are not available, nor is approach evident — Not clear whether — 2 mask sealing has high priority; could be addressed with separate test Physical Technical challenge — 1 connections, such with no precedent as tubes and wires, in current state must fit within of art volume, thermal constraints — Overall integration — 1 of movement, physiology, thermal requirements is far greater challenge than separate elements

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