U.S. Army Research Laboratory (ARL) employees within the Human Research and Engineering Directorate (HRED) are working to expand the use of modeling tools to assess and improve system performance, usability and overall ergonomic design.
Modeling and simulation are playing an important role in the engineering development of modern military systems, such as ground and aviation platforms, and will play an even greater role in the future.
The use of human factors engineering tools and techniques allow scientists, engineers and program managers to assess the accommodation of the intended user population for the system design early and continuously throughout the system lifecycle. This can help to reduce the time and costs required for successful development of military systems and help reduce the risk of not meeting requirements for human system integration.
In addition to system ergonomic design requirements, modeling and simulation tools are also used to assess mental and physical workload, manpower requirements, safety related issues and other areas related to human system integration.
One of the modeling tools that HRED uses is the Jack® human figure modeling software to assess the ergonomic design of military systems. Jack® is an interactive tool for modeling and analyzing human and other 3-dimensional (3D) articulated geometric figures and allows the user to develop models that represent a specific user population for whom the equipment is targeted.
Rick Kozycki, HRED, who is located at Aberdeen Proving Ground, oversees the application of the Jack® human figure modeling software tool used to assess ground and aviation platform designs. Cheryl Burns from HRED's Fort Knox Field Element is the lead for the analysis work on ground vehicle systems and Dave Durbin from HRED's Fort Rucker Field Element leads the research for the future vertical lift/joint multi-role or FVL/JMR program, which is the next generation of Army aircraft.
"It is very exciting to see whether or not a vendor's conceptual model for a vehicle design is actually feasible as in -- Can a Soldier wearing his/her gear get in and out of the vehicle? Can Soldiers in the crew pass ammunition up to the gunner so he/she can reload the 50 caliber machine gun? Can operators reach system controls to operate them?" said Pamela Savage-Knepshield, division chief, HRED's Human Factors Integration Division. "Finding answers to these questions early before any metal is bent saves the government time and money."
That's exactly what the team aims to accomplish.
Burns, an expert in ground vehicle systems has been with ARL since 1997. Prior to coming to ARL, she worked for the U.S. Army Materiel Systems Analysis Activity at Aberdeen Proving Ground as their senior intelligence officer. She spent time on government and industry panels to help write the requirements for the government to review designs of computer aided design (CAD) proposed drawings and ask for clarifications prior to prototyping the vehicles.
"Developers use CAD models at the beginning of a development program. If the government contract is not written correctly, it becomes difficult or is an additional cost for the government to acquire these models to review," said Burns. "Early review of models allows the government to ascertain if the contractor is meeting design specifications and to ask clarification of the contractor's design prior to building any mockup or prototyping.
"In relative terms, it is very cheap and easy to make design changes during this phase of the program as opposed to further downstream in the program after physical prototypes have been built. At that point your design is set and you have to start performing significant tradeoffs and cost can escalate exponentially to achieve the desired result."
The CAD files represent the virtual model of the helicopter and the armored vehicle while the Jack® software adds models of Soldiers.
"Using CAD files, we are able to see the actual design of a system in 3D on a computer and look at the design from any angle that we want," said Kozycki. "The Jack® software allows us to put simulated 3D models of Soldiers in the CAD models to evaluate the fit, reach and vision they would have in the real life physical version of that helicopter or armored vehicle. In order for HRED to perform an ergonomic assessment of a system design, we must have access to the CAD files of that design."
Kozycki said CAD files typically come from the vendor or contractor that is designing and developing the ground or aviation platform.
"Cheryl and Dave, as well as some of our other field element personnel, are helping HRED to gain access to the CAD files early in the acquisition process in order to apply human figure modeling tools to improve system performance," said Kozycki. "Without access to the CAD files, we cannot apply human figure modeling and would otherwise have to wait until an actual physical prototype of the system is built."
Durbin has been with ARL since 1988. Prior to coming to ARL, he worked for the U.S. Army Combat Readiness/Safety Center at Fort Rucker, Ala. He has teamed with Kozycki to conduct human-figure modeling for all current Army Aviation systems. In addition to using the modeling to help design current Aviation systems, he and Kozycki are working on the FVL/JMR program to ensure Soldiers will be accommodated in the next generation of Aviation systems.
"We are assessing volume of space requirements for FVL/JMR," said Durbin. "How big will the aircraft need to be to accommodate nine to 18 combat troops to include the equipment required for each of them to carry? It's important we model both the Soldiers and the equipment for an accurate assessment."
Durbin said that initial results of the modeling have been provided to industry to ensure that Soldiers and their gear will be accommodated in future aircraft.
Kozycki agrees.
"Some of the equipment that dismounted Soldiers and Army aviators wear are bulky and restrict body movement as well as increase the space required to operate, occupy and perform ingress or egress procedures," said Kozycki. "If personnel in a design can't fully access and view all displays and critical controls that they are required to operate, we need to know early and address this. It's important that with our modeling we try to replicate the exact situations the Soldiers will face."
Kozycki said that some design requirements used for accommodation in the past are outdated due to the added bulk of the current clothing and equipment ensembles and additional requirements for occupant protection.
For example, equipment such as a camelback worn may add an additional three to four inches of bulk to the back of dismounted Soldiers and changes the way they sit in a seat -- they are no longer able to sit as far back in the seat as they used to -- the seats in the past are no longer sufficient to accommodate personnel equipped with body armor, ammo, communications gear, protective masks and other equipment items that add bulk.
"The human figures that we use must also be equipped with models of the same mission essential clothing and equipment to perform an accurate assessment of the design. That is why we have also put considerable resources into developing clothing and equipment models that not only represent the additional bulk, but are suitable to perform interactive movement and dynamic posturing of the models in order to perform the system design assessment," said Kozycki. "Vehicle and aviation platform designs must plan for the equipment the Soldier wears or takes with them. In order to perform an accurate modeling and analysis, we have to keep updating our models to reflect realistic conditions, because the equipment constantly changes."
Soldiers cannot all be assessed the same.
"We also want to assess a design for the entire range of Soldier population that a system is required to accommodate," said Kozycki. "Does the seat move forward enough to provide sufficient forward adjustment to reach the pedals? Can the individual reach all critical flight controls? And, with the larger males -- is there enough space? Is the ceiling high enough? Can the seat go back far enough? Are emergency hatches and doors large enough to safely ingress and egress? There are many design parameters that must be examined to ensure that the entire target population is accommodated."
Human figure modeling is an important aspect in the design, usability and performance of the Army's ground and aviation platforms and has been used successfully.
"HRED has used human figure modeling to develop and test Army Aviation systems. The modeling results have been used by government and industry to improve the ergonomic design and functionality of the systems, assess anthropometric requirements and reduce analysis timelines," said Durbin. "Human figure modeling will continue to be used to develop and assess new and upgraded aviation systems -- it will continue to play an increasingly important role in the future as we work to reduce system design costs and shorten design, development and production times."
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