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5
Operational and Tactical Mobility
The AAN will be designed to project power via a battle force in the United
States that can be moved rapidly to the battle area to engage in decisive combat. The
force might be moved to a staging area first or, perhaps, directly to the battle area. In
either case, the force will have to move across land and water before engaging the enemy
in combat. This chapter discusses the operational and tactical mobility of the AAN battle
force. Operational mobility is defined as movement from the staging area to the battle
area. Tactical mobility is defined as movement in the battle area. Strategic mobility, the
movement of the battle force from the United States over several thousand kilometers of
land or sea to the staging area, is discussed in Chapter 9.
Mobility is critical because it dictates the pace of battle and the pace of resupply.
Fuel, one of the major logistics burdens, is closely linked to mobility. The capability to
resupply the force depends directly on the capability of moving supplies, equipment, and
personnel, as well as fuel and ammunition, to the battle area. A major objective of the
AAN will be to move the battle force to the battle area and close with the enemy at
speeds averaging 200 km/in, five times as fast as the speed in the Gulf War.
OPERATIONAL MOBILITY
For this discussion, the committee defined the range of operational mobility, the
movement from the staging area to the battle area, as 300 to 1,000 km. Two programs
that would address the operational mobility requirement are the loins Transport
Rotorcraft Program to develop an advanced transport helicopter and an advanced
tiltrotor program to develop a successor to the current V-22 Osprey ("super-Osprey"~.
According to briefings by representatives of the ARL and the Army aviation
community (Bill, 1997; Kerr, 1997; Scully, 1998), the present goals of both Arrny
programs are to lift 15 tons (the desired maximum weight of an advanced fighting
vehicle) up to 1,000 hen and to consume less fuel than present Army aircraft. Meeting
these ambitious goals will require more than tripling the lift capability of present Anny
utility helicopters or quadrupling the lift capability of the V-22 Osprey.
Many insiders are skeptical that the Army can meet these goals. For example,
the chief of the Aviation and Missile Command was reported to have said that a range of
perhaps 500 km, half the goal, was realizable. Increases in the fuel efficiency of aircraft
engines of up to 25 percent could be demonstrated, but 60 percent, the estimate for AAN
systems, would require "radical engine redesign" (Winograd, 1998~.
If the Army did meet its goals and could field a helicopter or tiltrotor aircraft
capable of lifting 15 tons, with a mission radius of 1,000 km and a cruising speed of
64
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OPERATIONAL AND TACTICAL MOBILITY
TABLE 5-1 Battlefield Mobility Trade-offs for Transport Aircraft
Fleet
Size
Fleet Flyaway Cost Flying Timeb
(billions of dollars) (hours)
250 1 1.75 49.3
500 23.50 24.7
750 35.25 16.4
1000 47.00 12.3
1250 58.25 9.8
1500 70.50 8.2
1750 82.25 7.0
2000 94.00 6.2
aAssumes cost of $47 million per aircraft
bAssumes the staging area is 1,000 km from the area of operations, 2,000 ground
vehicles are transported, arid a cruising speed of 325 km/in
65
325 km/in, it could cost as much as $47 million per vehicle. The Army Mobility
Integrated Thea Team estimated that the fuel required for such an air carrier mission
would weigh 22 tons (Bill, 1997; Kerr, 1997; Scully, 1998~. Table 5-] shows the
estimated flyaway cost and flying time for several sizes of rotorcraft fleets that could
transport 2,000 ground vehicles for a nominal AAN battle force.
The flying time in Table 5-1 was calculated by assuming that one vehicle would
be transported each trip, the cruising speed was 325 km/in, and the aircraft returns to the
staging area empty (or with a minimal loads. The estimates include only the time the
aircraft is in the air. No time was allotted for loading, transporting, or unloading
anything other than vehicles, such as fuel or other supplies. No time was allotted for
refueling, crew rest, etc.
The smallest fleet in the table comprises 250 aircraft, which would cost $11.75
billion and would require more than 48 hours of continuous flying time to transport
2,000 ground vehicles to the battle area. The largest fleet shown in the table is 2,000
aircraft, which could transport 2,000 vehicles in a single six-hour trip. However, this
fleet would cost $94 billion to build.
The JP-8 fuel required to transport the 2,000 vehicles to the battle area is 44,000
tons (2,000 trips x 22 tons/trip) for all of the fleets in the table. Assuming the
deployment weight of this nominal battle force with no replenishment for two weeks is
around 12,585 tons (see Chapter 2), the fuel required" to transport just the combat
vehicles by air would weigh as much as three times the entire battle force.
One could legitimately argue that this burden would be incurred in the staging
area and not by the battle force and that commanders would select staging areas with
ready supplies of fuel and water. Even so, the aircraft providing for the operational
mobility of an AAN battle force would add to the logistics burden, and might not be
affordable.
The aviation community has initiated a study to reduce the unit flyaway cost of the lift rolocraft
from an estimated $128 million per aircraft to $47 million.
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66
RED UCINrG THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
In some scenarios, the U.S. Air Force C-17 fleet planned for strategic airlift
could be used to convey the battle force from the staging area to the battle area. A single
C-17 could carry as many as five 15-ton AAN vehicles, and the flying time for one
round trip would be 2.2 hours. The planned fleet of C-17s will comprise 120 aircraft.
Using the entire fleet would require 400 trips, or three-plus trips per aircraft, for a nomi-
nal seven hours of flying time. In other words, this C-17 fleet is comparable to a fleet of
1,750 to 2,000 rotorcraft. (The obvious obstacle to relying on C-17s for operational
mobility would be the need for airfields in the battle area.)
The last Army-operated fixed-wing aircraft was the C-7 Caribou, which was
based on late-19SOs technology and could carry 30 passengers or a load of 5 tons. This
aircraft had excellent short take-off and landing characteristics, even from unimproved
air strips. The Army relinquished the Caribou to the Air Force in the 1960s, however, as
part of a redefinition of roles and missions by DoD.
The Army, therefore, faces a dilemma. On the one hand, the aviation research
and development domain of the Arrny is in rotorcraft, including tiTtrotor craft. Even if
planned developments are completely successful, the aircraft would not be able to meet
the AAN fuel efficiency goal, and a fleet big enough for the nominal force structure and
rapid operations of current AAN mission concepts would not be affordable.
On the other hand, aviation technology that would be better suited to the AAN
force structure and tempo of operations has been removed from the domain of the
Army's roles and missions. For example, some aerodynamic studies suggest that control
of the airflow over fixed wings could increase lift significantly (Bushnell, 1998~. Even if
the Army undertook a program to develop or improve fixed-wing aircraft, based on
existing defense policy, the Arrny would probably be denied pe~ission to procure it. In
short, although considerable basic and applied research would be necessary to field
improved fixed-wing aircraft to meet the Army's operational mobility needs, the Anny
would find it difficult, if not impossible, to support this research and insert the results
into its programs.
The capability of moving the battle force from the staging area to the mission
area is the prerequisite for battle. Operational mobility will be the first essential phase of
the combat and logistics operations for an AAN battle force. Even with major fiscal
support, the two present Army programs for transporting combat vehicles by air have
little chance of providing operational mobility for a nominal AAN battle force by 2025.
The loins Transport Rotorcraft could provide operational mobility in the range of the
AAN requirement (1,000 km), but only for a much smaller force than the AAN battle
force. A fleet required for an 8,000-man, 2,000-vehicle battle force would probably not
be affordable, either to acquire or to operate. Unless the battle force concept can be
altered to reduce the need for soldiers and vehicles on the ground, the AAN will have to
depend on the Air Force and Navy not only for strategic mobility (see Chapter 9) but
also for a significant part of its operational mobility. But neither of the Army's sister
services is now planning capabilities that could support an AAN battle force.
TACTICAL (BATTLEFIELD) MOBILITY
AAN doctrine not only emphasizes ground mobility and agility, but also greatly
increases the distances associated with tactical mobility. Combined with the objective of
reducing the logistics tail, the AAN mobility doctrine exemplifies the principles of
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OPERATIONAL AND TACTICAL MOBILITY
67
maneuvering and logistics support described by Sun Tzu in The Art of War more than
2,000 years ago:
The condition of a military force is Mat its essential factor is speed, taking
advantage of others' failure to catch up, going by routes Hey do not expect,
attacking where they are not on guard.
When you do battle, even if you are winning, if you continue for a long time
it will dull your forces and blunt your edge.... If you keep your armies out In the
field for a long time, your supplies will be insufficient.
Transportation of provisions itself consumes 20 times the amount transported.
Sun Tzu, lOO B.C.
Three generic solutions to the need for AAN tactical mobility are potentially
feasible. The first is the use of aircraft. Despite the problems described in the previous
section, the Arrny will have some rotorcraft (rotary wing or tiltrotor aircraft) that could
be used to move high priority troops or supplies for critical missions. But rotorcraft have
not been planned to move the bulk of a battle force on and around the battlefield as
rapidly as necessary to increase the rate of advance and engagement with the enemy to
an average of 200 km/in.
A second potential solution is a surface ground-effect (SGE) vehicle, such as the
wing-in-ground (WIG) vehicles being evaluated by the Navy (Box 5-~. These vehicles,
which are based on research begun in the former Soviet Union, operate close to a
resisting surface like water, ice, or snow (Skinner, 1998; Reeves, 19981. The
aerodynamic mechanisms that provide the lift are not well understood but appear to use
the air flow between the vehicle and the surface for more efficient lift and higher
forward speed than older ground-effect concepts for "air cushion" vehicles that propel
air downward against a resisting surface. WIG vehicles might be used for tactical and
operational mobility. However, the lift will first have to be better understood, which will
require some basic research. Also, the feasibility of flying in and out of the SGE flight
regime, to traverse broken or steep terrain must be explored.
The fuel consumption rates of WIG aircraft are estimated to be one-half to one-
third of rates for conventional aircraft at comparable speeds. This could translate to a
corresponding savings in the logistics fuel burden for strategic or operational airlift. In
addition, the speed and capacity of WIG aircraft could enable deployment, within AAN
time constraints and mission environments, of heavier materiel and ground systems than
could be transported by conventional aircraft. The U.S. Special Operations Command,
the U.S. Atlantic Command, and the Chief of Naval Operations Strategic Study Group
have all expressed an interest in WIG technology, but fundamental research would be
necessary (~) on decreasing wing loading to facilitate entering the SGE aerodynamic
regime, (2) understanding the type of air flow, and (3) determining why the flight of a
WIG aircraft is so quiet.
The third solution is to use ground-traction vehicles. Ideally, the AAN battle
force will operate with an advanced fighting vehicle weighing no more than 15 tons, but,
to provide tactical mobility for the entire force, it would also employ other ground-
traction vehicles weighing 15 tons or less. The committee made a considerable effort to
examine the technological underpinnings of this scenario and the obstacles and
opportunities it presents. Will a 15-ton, highly mobile, ground-traction vehicle with
o
a , , ,, ~ _ _ , , ,
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68
REDUCING THE LOGISTICS BURDEN FOR THE ARMY AFTER NEXT
BOX 5-1 Russian WIG Vehicles
The former Soviet Union secretly developed wing-in-ground (WIG) aircraft, also
called surface-ground effect (SGE) aircraft. Their lift capability comes from an
incompletely understood fluid phenomenon in which a high-pressure zone is created
between a low-flying object and the surface beneath it, such as ground or water. For
properly designed aircraft above a certain velocity, a high-pressure air cushion forms,
which keeps the aircraft above the surface. A possible explanation is that the laminar
(nonturbulent) flow of air beneath the vehicle enables it to maintain high forward speed
with little effort, resulting in high fuel economy compared to more conventional
aerodynamic concepts. The phenomenon can be observed in nature when large waterfowl
glide effortlessly close to the water.
The aircraft developed during the 35-year WIG program were designed to fly at
low altitudes over water, ice, and snow. WIG designs fall into three categories: (1) aircraft
that fly by SGE at all times, (2) aircraft that fly in and out of the SGE regime, and (3)
aircraft that use SGE only on takeoff and landing. Several Russian design bureaus are
currently selling WIG technology commercially.
The Russians have developed this technology to the point of demonstrating large
WIG aircraft, notably the Caspian Sea Monster, which has a maximum takeoff weight of
540 metric tons. This large aircraft has flown at 650 km/in (350 knots) just above a surface
of water or over very level terrain. The Caspian Sea Monster was considered to be a threat
to U.S. submarines and surface ships. It had four turbojet engines on each side near the
nose, and up to four power-augmented ramjets on the tail.
Numerous smaller WIG craft were designed and prototyped in the former Soviet
Union. For example, an early prototype of the Orlyonok (Eaglet) was about the size of a C-
130, had a takeoff weight of 100 metric tons, and a payload of 13.5 metric tons. A later
design for an Orlyonok (not constructed) would have carried a payload of 27 tons. Another
WIG design, known as the Lun, weighed 380 tons and was considered to be a threat by
Russia's Scandinavian neighbors because a fleet of 10 could have crossed the Baltic Sea
with minimal radar signature in 12 minutes and deposited 5,000 troops without warning.
Although WIG craft designed after the Caspian Sea Monster were smaller, a WIG
craft that could transport 2,000 metric tons was considered feasible. The Soviets pursued
WIG technology for naval and military concepts to the point of test-f~ring a missile from
the Lun. Once developed, this capability could have posed a serious threat to U.S. surface
ships. A large WIG could fly at 650 km/in, undetected by radar, and launch antiship
missiles. The program to develop a WIG missile capability ended when the Soviet Union
broke up.
The British reportedly confirmed the SGE phenomenon when a Vulcan bomber, a
210-ton aircraft, experienced an unexpected increase in speed of 20 to 30 percent and a
dramatic reduction in fuel consumption in low altitude flight (approximately 100 feet). The
speed was as high as 937 km/in. Although the delta-wing geometry of the Vulcan is not
optimized for SGE, the aircraft displayed unexpected endurance in this test flight.
Source: Skinner, 1998; Reeves, 1998
greatly reduced logistics demand possible by 2025? If so, what would the vehicle be
like? To answer these questions, the committee drew heavily on the Tong-term work of
the Anny's TARDEC (Tank-Automotive Research, Development and Engineering
Center) and the Corps of Engineers Waterways Experiment Station (WES) on vehicle
dynamics and the development of ground-traction vehicles.
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OPERATIONAL AND TACTICAL MOBILITY
Wheeled Versus Tracked Vehicles
69
Ground-traction vehicles move either on wheels or tracks. Other factors being
equal, wheeled vehicles are generally weigh less than tracked vehicles, have greater fuel
economy, and require less maintenance. Tracked vehicles typically provide more robust
mobility over difficult terrain, soils, and obstacles (that is, they are less likely to become
stuck). Therefore, a reasonable objective for AAN is a wheeled vehicle, either manned or
unmanned-provided it is demonstrably either equivalent to a tracked vehicle in
mobility or "mobile enough" for a particular mission.
In many terrains, wheeled vehicles are fully capable of performing the mission;
witness the large number of wheeled combat and support vehicles used by armies
worldwide. In addition, many wheeled vehicles use commercial engines and
transmissions and have far better fuel economy than tracked vehicles (Petrick, 1990~.
Many studies have been done comparing the performance of wheeled and
tracked vehicles. Choosing between wheeled and tracked vehicles has, in fact, at times
been an emotional subject in Anny circles. In most cases, the Army has selected the
"safest" approach for combat missions, namely, tracked vehicles, even though the cost of
acquisition and logistics support has been higher than for wheeled vehicles.
Previous studies have led to the generalization that wheeled vehicles are most
suitable below 10 tons, tracked vehicles above 20 tons, with a gray area in between
where the choice depends on operating and support costs, terrain, and logistics. Based on
this general rule, a 15-ton wheeled vehicle for AAN would be the Army's preference but
would not be a clear-cut choice.
M&S (modeling and simulation) can yield some insights into the advantages and
disadvantages of wheeled and tracked vehicles for AAN operations. As noted previously,
a starting point for M&S of combat vehicle performance is the NRMM (North Atlantic
Treaty Organization Reference Mobility Model). The NRMM describes the following
five factors as limits to vehicle mobility.
Maneuver-controlledt speed is the limit imposed by man-made or natural
obstacles, such as forests or rivers.
Force-controlled speed reflects the inability of a vehicle to move through
unfavorable soil conditions or up a steep slope.
Visibility-controlledt speed is the limit on speed imposed by the driver's inability
to see what is over the next hill or around the next corner.
Rid~e-contro1~ledt speeds is the limit on speed imposed by the amount of energy the
human body can absorb while moving over rough terrain.
Tire-controlled speed is the speed at which tires begin to disintegrate.
WES has conducted exhaustive tests comparing wheeled and tracked vehicles in
tees of these five factors (DA, 19911. As expected, tracked vehicles exhibited a higher
maneuver-controlled speed. (The wheeled vehicles that were tested tended to nose down
and had insufficient traction to exit linear obstacles, such as ditches.) The tracked
vehicles also moved better over unfavorable soil because of their larger area of ground
contact. However, tracked vehicles had no advantage in visibility-controlled situations
and no inherent advantage in ride-controlled situations. (WES has found that combat
vehicle speed in many areas of the world is ride-controlled.) Enabling technologies that
could raise the limit of each speed-limiting factor are described below.
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70
Maneuver-Controlled Speed
REDUCING THE LOGISTICSBURDENFOR THEARMYAFTER NEXT
Some obstacles, such as dense forests and large rivers, cannot be traversed by
either wheeled or tracked vehicles. Remote sensing could offer the commander
alternative routes to an objective (see the discussion of situational awareness in Chapter
6~. Software to speed processing of obstacle information gathered by the sensors is
especially important. Active suspension and some type of"ditch-ejector" would assist a
wheeled vehicle in breaching minor linear obstacles. A "smart" suspension system
would increase both cross-country speed and improve the crossing of small trenches and
obstacles.
Force-Controlled Speed
A high ratio of horsepower to weight would help overcome this limit. Remote
sensing of soil conditions would be useful for determining the soil conditions of various
routes. Guaranteed traction to each wheel can be accomplished with slip control.
Articulated powered joints, to permit both the coupling of modular vehicle units and the
powered elevation of selected units, would also help overcome this limitation and would
enhance the vehicle's ability to cross trenches and small obstacles.
Visibility-Contro/~led Speed
Visibility-enhancing sensor systems will be key to overcoming this limitation.
These sensors could "peer through" (penetrate) smoke, obscurants, and foliage far
enough to allow the driver to increase speed. Decision aids, a heads-up display, and
elevated optics would also help drivers maintain high ground speeds when normal line-
of-sight vision is limited.
Ride-Controlled Speed
The impact energy transmitted to the driver could be limited by active-
suspension technology or mechanical isolation of the cab. A radical approach that would
eliminate this limitation would be to remove the driver (and crew) from the vehicle; that
is, to use uncrewed vehicles. Evidence has shown that drivers can adapt to the severe
"jostling" (trilateral acceleration) associated with cross-country driving, but soldiers
rarely experience these conditions frequently enough during training to become
acclimated because the risk to both the driver and the vehicle is considered unacceptable
to most commanders. Vehicle simulation trainers with three-dimensional movement
would be useful for training drivers to operate at high speeds over rugged terrain.
Tire-Controlled Speed
New tire materials and centrally controlled tire inflation capability (assuming the
tires are pneumatic) could help overcome this limitation. Control of tire pressure would
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OPERATIONAL AND TACTICAL MOBILITY
7
r 1
match the vehicle tires to the soil conditions. Run-flat tires, which will soon be
commercially available, would also be useful for wheeled combat vehicles with
pneumatic tires. Tire and tread materials that minimize the heat caused by deformation
would reduce not only the wear due to thermal deterioration but would also reduce the
significant thermal signature of both wheeled and tracked vehicles.
General Comments
.
The committee compared the advantages and disadvantages of future wheeled
vehicles supported by the enabling technologies described above with tracked
vehicles in terms of meeting AAN performance objectives, as well as in terms of
reducing logistics burdens. Given the AAN objectives, the committee concluded that the
Army should focus on advanced wheeled vehicles for the AAN. Of course, trade-off
analyses will be necessary to confirm this preliminary conclusion. The trade-off analyses
should quantify the relative advantages of various wheeled and tracked vehicle
configurations using the distributed M&S environment.
A suitable family of vehicles for the AAN would incorporate lightweight, high-
performance materials, possibly organic-matrix or metal-matrix composites, nonconven-
tional metal alloys, or intermetallics (see Chapter 4 and Appendixes C and D). These
vehicles would consume less fuel and require fewer spare parts and maintenance support
than current vehicles. Most important, the AAN commander would have a mobile force
that could traverse moderate terrain at more than 130 kilometers per hour (80 miles per
hour). ("Moderate terrain" excludes both impassable areas, such as the Swiss Alps, and
favorable areas, such as the Saudi Arabian desert; in the latter, higher speeds may be
possible.) The vehicles would have a rich array of sensors to ensure situational aware-
ness and could be operated with a minimal or even no crew.
However, the 15-ton vehicles in this family will have much less protective armor
than current battle tanks. They may be equipped with a variety of active protection
devices in addition to armor (see Appendix D). To survive the most lethal enemy fire,
they would depend mostly on avoiding being hit through situational awareness, agility,
and stealth.
The committee, unlike many individuals in the Army, is not convinced that the
power plant for future vehicles ought to be either electric or hybrid-electric. As the
committee noted in Chapter 4, the duty cycles typical of suggested AAN operational
concepts might not give hybrid vehicles an advantage in fuel economy over straight
mechanical drives. Careful exploration of the likely duty cycles for typical AAN
missions, as part of rigorous design trade-off analyses that include other considerations,
such as electric power for armaments and other subsystems, will be necessary to
determine the optimal power plant and drive configuration (see Appendix E).
The main armament of the lead combat vehicle may not be a gun capable of
kinetic energy penetration of heavy armor. A quantified study of trade-offs
other platforms or systems to defeat heavy armor (see Chapter 6~. The committee
believes that M&S is the only way the Army can evaluate and assess
requirements for AAN combat vehicle designs.
may favor
competing
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72
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
Remote Sensing to Enhance Battlefield Ground Mobility
A continuing concern of the Arrny mobility community has been that detailed,
accurate terrain data for cross-country movement might not be available from pre-
operation mapping. An initiative under way by the National Imagery and Mapping
Agency is to map more than 80 percent of the worId's surface (the missing areas will be
in the polar regions). However, the data will have a vertical resolution of only 30 meters,
which is not adequate for planning cross-country movement. Although the sensor
technology, when used with a conventional aircraft as the platform, can acquire data at a
10-meter resolution, translating the data into a usable digital product at maximum
resolution requires enormous computational capabilities; each hour of data acquisition
would require 50 hours of processing time.
The U.S. Army Corps of Engineers' objective for supporting military operations
is to provide a digitized elevation map for a 90-km2 area to a vertical resolution of one
meter within 72 hours, from the start of data acquisition by an aircraft (possibly a UAV)
until the digital product is delivered to the operational commander. Although this
capability would provide a terrain baseline, many things can change in a combat area in
72 hours. The enemy could blow up a bridge. Rain could make a route impassable. The
destruction of a dam could flood an area. Enemy sappers could construct an impassable
abatis.
In addition to baseline data, a commander planning or executing a maneuver
from point A to point B would benefit from real-time updates of changes in the terrain
(i.e., physical and cultural geography). The sensor system, perhaps linked to the global
positioning system for accuracy, would report changes to the terrain database in the area
of potential maneuver routes for all operations. Developing this capability would require
the resources and cooperation of WES, TARDEC, the Corps of Engineers Topographic
Laboratory, and perhaps others.
Reducing the Size of Vehicle Crews
Reducing the crew size in a fighting vehicle can reduce the vehicle weight
considerably because the enclosed volume can be reduced, requiring less material,
particularly less armor. Reducing the size of the vehicle can also aid in stealth and agility
trade-offs with the weight of passive armor (Appendix D). The ultimate in crew
reduction is an unmanned (robot) vehicle.
Besides the 15-ton crewed fighting vehicle, the Army has considered 7-ton
crewed and uncrewed vehicles. if progress is made in research and development, even
smaller unmanned ground vehicles (UGVs) designed for special combat purposes may
be feasible. Specialized UGVs might range in weight from a ton down to just a few
kilograms.
The various military services are developing UAVs (unmanned aerial vehicles)
and unmanned undersea vehicles (UUVs), in addition to UGVs. At present, the principal
drivers for these programs are operational and performance objectives rather than
logistics. Many factors specific to each vehicle concept and its intended use in the force
affect whether an unmanned vehicle will increase or decrease logistics support
requirements.
Smaller UAVs and UGVs could be used as sophisticated mobile sensor systems,
" or soldier-safety alternatives (e.g., for clearing mines and
"smart weapons,
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OPERA TIONALAND TACTICAL MOBILITY
73
reconnaissance), rather than as potential substitutes for crewed vehicles (or dismounted
soldiers), and they may add to the logistics burdens. If an unmanned vehicle partially or
completely replaces a crewed vehicle, a key consideration is the extent to which the
unmanned vehicle (or several of them) reduces the number of manned vehicles necessary
for a given operational capability. Logistics support requirements will also depend on
whether an unmanned vehicle is tale-operated, semi-autonomous, or fully autonomous.
Rational decisions about these complex trade-offs require at least unit-level engagement
analyses based on detailed system/subsystem engineering models (see Chapter 3~.
The use of robotics science and technology to provide automated vehicle
subsystems-enabling reductions in crew size for manned systems- seems a promising
way to reduce vehicle weight and volume. Furthermore, this incremental approach to
removing the human soldier from fighting platforms seems more realistic than
unmanned vehicles for reducing logistics burdens in the AAN time frame.
Over time, the general approach of subsystem automation could be extended to
the automation of some of the vehicles in a platoon of vehicles (or analogous tactical
unit that maneuvers and fights in close coordination), with human platoon commanders
or other crew in one or more of the vehicles. in effect, the platoon would become a
"minimally crewed system," with some vehicles acting as automated subsystems. This
"semi-automated platoon" approach to vehicle automation would provide invaluable
experience and a test bed for technologies that could eventually (well after 2025) lead to
fully autonomous fighting vehicles with the flexibility and effectiveness of today's
mounted soldiers.
UGVMobility
The five NRMM (NATO Reference Mobility Model) factors that affect the
cross-country mobility of crewed vehicles can also be applied to UGVs:
.
.
.
.
.
Maneuver-Controlled Speed. If UGVs are smaller than crewed vehicles with
similar functionality, they may be more capable of traversing some terrains, such
as narrow trails. There will always be some obstacles that a ground vehicle
cannot overcome, whether or not a human is aboard.
Force-Controlled Speed. Because a UGV does not need a crew cabin, the engine
can be larger for the same total system weight, yielding a higher ratio of
horsepower to weight. Increasing this ratio is useful for attaining high force-
controlled speeds.
Visibility-Controlle`1 Speed. The observer-operator of a tale-operated UGV could
have a wider range of vision than the driver of a crewed vehicle. The
development of sensor systems to improve access to terrain data for drivers of
crewed systems will also contribute to UGV development.
Ride-Controlled Speed. UGVs may have the greatest advantage over crewed
vehicles in this area. The ride-conkolled speed limit for a UGV is the speed at
which mechanical shock and vibration will damage the vehicle's mechanical or
electronic assemblies. For a given terrain, this speed may be much greater than
the speed at which a human occupant can avoid injury and retain operational
control of a vehicle.
Tire-Controlled Speed. Unless the tires are lighter or of a different type, UGVs
would have no direct advantage over crewed vehicles in this area.
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74
Robot Vehicles
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
A large number of robot vehicles are either in production or under development
worldwide. As Table 5-2 shows, most of them are in the United States, where more than
50 percent of the manufacturers and developers for all of the vehicles in the table are
located (UVH, 1997~. In terms of the concepts under development and expenditures,
most of them are UAVs. However, even after 20 years and $3 billion dollars, the devel-
opment of UAVs has not been a complete success. Some of the problems are with the
aircraft itself, but the major difficulties involve nonaeronautical problems, such as com-
munications, control, electromagnetic interference, and video transmission (Crock,
1997~.
Although much of the UAV activity has been led by the Air Force and Navy, the
Anny also had a program for a high-attitude UAV called "Hunter" (terminated in 1998)
and has been given the responsibility of testing a tactical UAV, the Outrider, for low
altitude operation. These UAVs, as well as the rest of the U.S. military developmental
program, are platforms for sensors and the communication of intelligence, not weapons
platforms. At the research level, however, both the Navy and Air Force have expressed
interest in potential weapons-bearing air vehicles (uncrewed combat air vehicles).
Table 5-2 also shows that UGVs have not received as much emphasis as UAVs
and WVs. Only 17 percent of the worldwide programs by number are for ground
vehicles, and only one is currently in development in the United States. Research on
UGVs, which the committee considers to be prime candidates as special-purpose
vehicles in AAN applications, has laggedfar behind the research on US Vs. The reason
for the lag may be that the mobility control environment for traversing terrain is more
complex than the relatively homogenous control environments for flight through air or
travel under water. in addition to communications and control challenges similar to but
greater than those faced by UAVs and UUVs, UGVs must traverse varied soils and
terrain. Determining and executing a path, negotiating or avoiding obstacles (natural and
man-made), and maintaining or recovering functional traction (avoiding upsets) are
challenges UAVs and WVs do not face. ideally, UGVs will operate autonomously, but
most existing models are tale-operated; that is, they have partial autonomy but are
operated by humans at a distance from the vehicle. Among the various means being
investigated to control UGVs in this difficult environment are radio line-of-sight, fiber-
optic cable, and hard wires.
The UGVs currently produced in the United States run the gamut from small
special-purpose devices used by police departments for explosives detection and
surveillance, to vehicles the size of construction backhoes used for ordnance removal, to
armored bulldozers or tank-like vehicles used for mine detonation (UVH, 1997~.
Although these vehicles are listed in Table 5-2 as "in production," in most cases the
production volumes are very small.
The Arrny hopes to benefit from progress in the development of communication
and control for UAVs and UUVs and has several memoranda of understanding with
other service programs to share in the technological progress on unmanned vehicles.
Obviously, Army resources should be invested in Army-unique ground mobility
requirements for UGVs rather than in duplicating the efforts of other programs on
unmanned vehicles.
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76
Current UGVApp/tications
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
When the committee reviewed the Army-unique technological requirements for
robot vehicles, it became apparent that the present Army program is part of the
consolidated effort under the loins Robotics Program (IRP) directed by the Office of the
Secretary of Defense. The IRP program includes a number of components whose names
indicate their objectives: Vehicle Teleoperation Capability, Tactical Unmanned Vehicle,
Robotic Ordnance Clearance System, Basic Unexploded Ordnance Gathering System,
UGV Technology Enhancement and Exploitation (UGVTEE) Program, and the loins
Architecture for Unmanned Ground Vehicles (DoD, 199764.
The focus of the UGVTEE program is on exploiting research by other DoD and
government agencies, as well as industry and academia that meets current Army needs.
UGVTEE includes field experiments to help develop the optimal interaction between
soldier users and robot-vehicle technologists. A successful robotics program requires,
first, that the robot vehicles have the mechanical and technical capabilities to execute the
missions assigned to them. Second, the soldier users must know how to make the best
use of those capabilities. Third, users must become acclimated to (i.e., "comfortable")
working with a mechanical adjunct.
A series of UGVTEE field exercises, under the headings of Demo ~ and Demo
1l, are using tale-operated and supervised high mobility multipurpose wheeled vehicles
(HMMWVs) to test and evaluate the relationships between users and machines (DoD,
19973; DoD, 1997c). The committee believes these exercises should be continued as
more advanced robotics and control technologies for automated vehicle systems are
developed. The next step will be Demo III, sponsored by DARPA and intended both to
increase the capabilities of supervised and semi-autonomous vehicles and to develop the
user-vehicle interface.
The committee recommends that the Army continue lending its full support for
UGV demonstrations and development. Demo {IT will be necessary to the Army's
continuing effort to understand and exploit UGVs. The Army programs in UGVs are
conducted by the ARL, TACOM, with support from the WES, and the Army Aviation
and Missile Command. Demonstrations of UGVs for the Army are coordinated by the
Joint Program Office, Unmanned Ground Vehicles and Systems, which is located at
Redstone Arsenal in Huntsville, Alabama, and is similar in organization and function to
the Joint Program Office for UAVs.
Future Applications for UGVs and Required Technologies
A variety ot programs have been proposed for UGVs, ranging from somewhat
simplistic tethered vehicles to tale-operated units and semi-autonomous and fully
autonomous vehicles. These concepts range in size from full-scale vehicles to matchbox-
sized surveillance devices. A summary of proposed applications, compiled by the
Institute for Defense Analyses, is listed below (IDA, 1996b).
security, such as interior and exterior security of facilities, rear area security, and
convoy security
robot engineer vehicles to perform specialized functions, such as breaching
obstacles and mine fields; digging emplacements and fortifications; detecting,
recovering, and detonating mines; and crossing gaps
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OPERA TIONAL AND TACTICAL MOBILITY
77
combat support functions, such as decoy and deception, laying wire or cable,
evacuating casualties, and eliminating obstacles
robot trucks and other logistic vehicles for resupplying, rearming, and refueling
other vehicles
· RSTA (reconnaissance, surveillance, and target acquisition) vehicles for robot
scouts, special forces vehicles, and reconnaissance for nuclear, biological, and
chemical warfare agents
. specialized vehicles for urban operations
· robot vehicles as direct-f~re platforms, howitzers, air defense weapons, nonlethal
weapons carriers, or countersniper vehicles
Advanced capabilities required to support autonomous vehicles will vary,
depending on the tasks the vehicle is required to perform. For autonomous vehicles to
serve as RSTA vehicles or as direct-fire platforms, they will have to have the following
capabilities:
secure communications and control
data compression
enhanced displays for remote vehicle control
autonomous path following and obstacle avoidance
automatic target tracking
precise real-time location and identification of friendly and enemy units and
equipment, including onboard identification of Fiend or foe (TFF)
precision targeting and target servicing
automatic registration of killed targets
By 2025, fully automated, autonomous systems should be capable of emulating
various functions of a crewed vehicle or dismounted soldier, but they will still lack
abstract decision-making capabilities and other "thought-like" capabilities that involve
creativity and ingenuity. These robots will range in size from less than a cubic
centimeter to full-sized air and ground vehicles. Autonomous vehicles will be capable of
engaging in combat missions involving reconnaissance or mine detection and clearance,
as well as serving as weapons platforms for direct and indirect fire. Autonomous
vehicles may also deliver supplies and ammunition to ground troops, carry bulk supplies
to ports of embarkation, and perform other combat support tasks.
Some of the logistics issues related to automated subsystems in a vehicle, as well
as to fully autonomous vehicles, are obvious. Compared to a soldier, automated
subsystems do not eat or drink, do not need medical care, do not sleep, do not need
billeting, and can be squeezed into small volumes. Nevertheless, the logistics support to
maintain fully autonomous systems could be considerable, including mechanical
maintenance, computer software, and mission planning requirements, in addition to fuel
and energy requirements. Less obvious advantages, but the primary logistics advantage
for AAN planning, are potential reductions in weight that could be achieved by
incorporating robotic technologies into future combat vehicle designs to reduce crew
size and to increase combat effectiveness, which could ultimately reduce the number of
vehicles needed for the battle force.
The committee does not foresee a completely autonomous AAN battle force.
One Army officer told the committee that he could foresee a robot wingman for his tank,
but he was convinced that there had to be at least one manned vehicle for effective
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REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
combat (Brendel, 19974. If automated vehicles are used in the AAN, the committee
believes that a combined force of autonomous and semi-autonomous vehicles, rather
than a fleet of fully automated vehicles, will best meet AAN mission requirements.
The committee suggests that the Arrny reevaluate the modes of combat in 2025,
when the purpose of"combat" vehicles will not be limited (as current tanks are now
limited) to "shock," intimidation, and engaging enemy combat vehicles. Designing a
single combat vehicle that can play multiple roles will diminish its overall effectiveness.
A family of vehicles with common logistics support characteristics, designed to perform
complementary functions that increase the survivability of the entire force, would
probably be more effective. The evolution of weapons platforms in both the Air Force
and Navy demonstrates that direct "eyeball to eyeball" engagement with an enemy in the
air or on the sea is not practical (Wilson, 1996~. The Army should consider whether
direct engagements by future ground combat systems will be practical.
DISTRIBUTED MODELING AND SIMULATION
ENVIRONMENT FOR VEHICLE DESIGN
Status of Current Modeling and Simulation Tools
The NRMM resulted from a significant development program, carried out
primarily by WES and TACOM in the late 1960s and continuing through the 1970s, to
develop the M&S capabilities required for vehicle system mobility (DoD, 1974~. It is
based on speed and tractability parameters that characterize a vehicle's mobility. Once
specific values for these parameters have been established (or assumed) and a terrain
database characterizing the field of operation is available, the NRMM can predict the
time required to move from position A to position B in a tactical environment. Routing
algorithms in the mode! select the path of shortest time, avoiding areas of low speed or
poor traction. However, the mobility criteria in the NRMM are based on empirical
characterizations of vehicle performance, which are significantly influenced by the
characteristics of past and present vehicles. Although the NRMM's basic predictive
capability for ground vehicles will require some improvements, it represents an asset that
could be used effectively and built upon to assess AAN vehicle design and mobility
requirements.
The NRMM has no capability to model vehicles or mobility concepts that travel
off the ground, that is, in the vertical dimension that AAN planners wish to use for in-
theater air-mobile operations. In addition, current NRMM implementation, together with
supporting M&S tools for engineering analysis of vehicle performance, has significant
limitations in the simulation of key elements of vehicle performance (see Box 5-2~.
For instance, the VEHDYN (vehicle dynamics subsystem) in the NRMM
represents only one-dimensional mobility, straight-line motion on the ground. The
NRMM has no capability to represent the three-dimensional dynamic motion of a
vehicle traveling at high speed over rough terrain, so it cannot simulate the effects of
active suspension or traction control, hybrid-electric propulsion systems, and related new
technologies that will have to be assessed to find the best design for achieving the
revolutionary mobility objectives of the AAN.
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OPERATIONAL AND TACTICAL MOBILITY
Existing vehicle modeling tools
cannot be used to assess the perform-
ance or logistics benefits of advanced
subsystems and related mobility-
enhancing technologies that might en-
able a vehicle to operate cross-country
at high speed. Nor can they predict fuel
consumption or plan routes for ad-
vanced technology systems, based on
realistic simulations of duty-cycles and
corresponding engine power demands
(see Appendix E for an example of this
kind of analysis for a civilian vehicle).
Engineering models that can accurately
predict speed, traction, and fuel con-
sumption for vehicles with active sus-
pension, all-wheel traction control,
electric drive, power sources other than
internal combustion engines, and a host
of other advanced technologies that may
be required to achieve AAN off-road
mobility objectives have yet to be developed. Tractional force models that represent
fundamental physical interactions between the traction surface and a soil or similar soft
surface are not yet adequate to mode! high-speed cross-country travel.
Accurate simulations of differences in fuel consumption or traction of various
system designs under varying operational scenarios (duty cycles), will require models
that include realistic representations of the physical processes that determine these
important system-level performance characteristics. Without these "first-principles"
models, trade-off analyses for alternative designs will be inadequate- unless physical
prototypes of the alternative systems are constructed and tested to obtain validated
initializing data for the heuristic relationships used by simpler models. Unfortunately,
the committee found no evidence that the Army has begun to develop, or has plans to
develop, models at the vehicle-system or mobility-subsystem level that would
incorporate sufficient "f~rst-principles" modeling to simulate traction and fuel
consumption for ground vehicle concepts that are still in the design stage (before
prototyping). First-principles modeling capability is a prerequisite for the distributed
hierarchical M&S environment to become a reliable too! for making rational trade-offs
among vehicle characteristics, tactical alternatives, and force structures in terms of
logistics burdens and revolutionary mobility.
Advances have been made in characterizing soil surface conditions as a function
of weather, but accommodating terrain data from remote sensors will require further
refinements. Recent developments reported by WES in predicting soil or terrain
characteristics based on historical weather information appear to be promising, but they
must be linked with (1) advanced information systems for situational awareness and (2)
mobility M&S tools for system performance and analyses of logistics trade-offs.
79
BOX 5-2 Limitations in M&S Tools for
Engineering Analysis of Ground Vehicle
Concepts
Engineering models do not accurately
predict speed, traction, and fuel
consumption.
Model parameters do not account for
vehicles with:
· active suspension
· all-wheel traction control
· electric drives (including hybrid
electric)
· power sources other than internal
combustion engines
Tractional force models based on soil
mechanics are not adequate for AAN
speeds.
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REDUCING THE LOGISTICS BURDEN FOR THE WAFTER NEXT
Technology Extensions
Considering the myriad tactical and materiel alternatives that must be integrated
to create an effective, logistically supportable AAN battle force, better M&S tools will
be critical to making rational trade-offs in the time available. Systematic development
of highly mobile systems will require advances in M&S technology in three areas: (1)
off-road mobility analysis, (2) mission rehearsal analysis, and (3) driver training for high
mobility. Each of these areas is discussed below.
OJ/-Roadt Mobility Analysis
M&S capabilities to support off-road vehicle mobility have not kept pace with
technological advances in vehicle subsystems or with AAN mobility requirements. A
broad base of M&S tools will have to be developed (Box 5-3) to meet AAN vehicle
system performance and logistics objectives. Significant advances are required in the
technology for modeling off-road traction, surface and air propulsion, and related
mobility factors. The Anny can take advantage of basic developments in vehicle
dynamics, M&S software, hardware-and-driver-in-the-Ioop vehicle driving simulators,
and DTS (distributed interactive simulation) of vehicle concepts. The obsolete VEHDYM
subsystem of NRMM should be replaced with the simulation software already being
used by TARDEC and commercial vehicle manufacturers.
Predicting the Faction of highly mobile vehicles on soft soils, including the
effects of traffic on soil, will require significant improvements in modeling. Both
theoretical and empirical models of the interactions between tires or Packs and soil will
be necessary. These models must give reasonably accurate predictions of tractional and
lateral forces as a function of spindle position, velocity, and tire or Back speed.
Extending the current modeling capability will enable the Arrny to evaluate the benefits
of advanced technology subsystems, such as active suspension and Faction control,
electric drives, and articulated vehicles. With this capability, the Anny would have the
data necessary for making tactical mobility assessments using the NRMM.
Synthetic environment modeling of soil characteristics, terrain geometry, and
cultural features affecting both ground and air mobility will have to be substantially
improved for AAN system analyses. Soil characteristics, both surface and subsurface,
which are critical to mobility modeling, must be incorporated into databases that can be
populated with data obtained through field tests or in-theater measurements. Terrain
geometry and databases should be fully three-dimensional, including the characteristics
of obstacle types, such as rocks, Togs, and other geometric features that affect mobility.
Cultural features, such as brush, small Pees, and human-buiTt obstacles, that can
influence both ground and air mobility should also be incorporated.
Empirically based mobility models contained in the NRMM will have to be
updated to take advantage of improved capabilities for simulating vehicle dynamics.
Knowledge bases and expert systems technology could be incorporated to help the Arrny
assess AAN mobility alternatives. Mobility characteristics associated with active
suspension and Faction control, local sensing of terrain data, and other advanced
technologies for vehicle subsystems must be incorporated into the NRMM tactical
mobility representation. These and other extensions to the existing NRMM will be
essential for assessing the kade-offs among a wide range of concepts and technologies
for AAN vehicles and advanced mobility.
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OPERATIONAL AND TACTICAL MOBILITY
81
BOX 5-3 Mobility M&S Technology Developments
Tractional models for high-speed vehicles on soft soils
. effects of prior traffic on soil
· tire/track soil interaction
Synthetic AAN environment modeling for distributed interactive simulation
· soil characteristics
· terrain geometry
. cultural features affecting surface and air mobility
Extended empirically based NRMM mobility models
. dynamic simulation capability
High fidelity, real-time models of AAN vehicle concepts for hardware
and soldier-in-the-loop simulation
.
traction and vehicle suspension models
· active suspension and traction control models
· hybrid-electric power train models
Air mobility models
.
in-theater mobility of an AAN force
. integration into next-generation mobility analysis software
Fuel consumption models that account for
· energy dissipation at interface of tire or track with soil
· interaction with cultural features
· active suspension and traction control
· hybrid-electric power trains
. vehicle speed and maneuvers
Motion-based simulators can test hardware concepts in interactions with human
drivers (hardware-and-soldier-in-the-Ioop simulators). Simulators would provide a rapid
and relatively inexpensive way to experiment with AAN vehicle concepts and
technologies in a "virtual proving ground." The uncertainties associated with vehicle and
driver performance at the high cross-country speeds being considered for AAN could be
quantified through simulators.
In summary, the mobility assessment models currently implemented in the
NRMM are based on conventional vehicle configurations and are limited to land
mobility; they cannot represent all of the technology and subsystem options available for
the AAN. The Army will need engineering M&S extensions, and their associated
mobility representations in the NRMM, to analyze revolutionary AAN land-based
systems. The following high fidelity, real-time modeling capabilities will be required:
traction and vehicle suspension models
active suspension and traction control models
hybrid-electric power train models
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REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
hardware-and-soldier-in-the-Ioop vehicle concept simulators that can incorporate
results from the subsystem models into a virtual proving ground approach for
system testing
DTS models for analyzing the performance of multiple vehicles as a fighting
unit, incorporating results from the virtual proving ground
This degree of linking across levels of M&S capability while simulating the real-
time behavior of systems and drivers with enough fidelity to yield dependable
predictions of the performance characteristics of vehicle systems and tactical units will
require advanced computing capabilities. Models and their computer implementation
will have to be targeted for the specific class of simulator (e.g., DIS nodes and
developmental virtual proving ground simulators).
In addition to these M&S extensions and improved linkages for modeling and
simulating ground mobility, air mobility models that can represent the in-theater
mobility of an AAN force should be developed and integrated into a next-generation
mobility analysis software package. These models should focus on the chosen air
mobility mechanism (e.g., helicopter, tiTtrotor, or fixed-wing aircraft). in addition, if any
of the surface-effect vehicles prove to be viable, realistic design and trade-offs among
design alternatives will require an entirely different set of terrain data.
The Army will also require fuel consumption models for both air and ground
systems. The ground versions of these models should account for energy dissipation at
the interface of tire or track with soil, interaction with terrain cultural features, effects of
active suspension and traction control technologies, the performance of hybrid-electric
power trains, and the effects of vehicle speed and maneuvers. First-principles models of
vehicle power train and propulsion subsystems and their interactions with the tactical
environment could predict consumption rates as a function of vehicle design and use.
Fuel supply is emerging not only as a major AAN logistics burden but also as a critical
hurdle to meeting AAN sustainment objectives. Therefore accurate predictions of fuel
consumption will be essential to meeting AAN goals.
Mission Rehearsal Analysis
Mission rehearsal analysis could be based on the same M&S capability used for
AAN logistics trade-off analysis. During the committee's deliberations, high-fidelity
mission rehearsals using mobility M&S tools was identified as an important means
of improving logistical efficiencies
through better tactical and mission sup-
ply planning (Box 5-4~. Credible mis-
sion rehearsal simulations would enable
commanders to estimate the supplies
required for a specific AAN mission
more accurately. Logistics provisioners
could then transport "just enough" ma-
terie! into the battle zone, reducing the
logistics burdens of transporting more
materiel than is needed and having to
manage the excess during the operation.
BOX 5-4 M&S Tools for AAN Mission
Rehearsal Analysis
· Planning tactics
· Determining supply requirements
· Designing supportable vehicles
· Predicting fuel requirements
. . . . . . . .
· M~mmlzmg mlsslon loglshcs
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OPERATIONAL AND TACTICAL MOBILITY
Implementations of the NRMM
on personal computers, which were
demonstrated to the committee at WES,
showed that these mobility M&S tools
could be the foundation for mission
rehearsal analyses. Although significant
development and extension of the basic
tools will be necessary to represent AAN
vehicle systems and tactical operations,
most of this work would also be
applicable to analyses of performance
and logistics trade-offs. The
technological challenge will be to create
tools that can be used by war fighters
and to implement aIgorithrns that can run
on inexpensive field computers.
Driver 1 raining
Moving combat forces at the
high speeds required for AAN operations
will require that drivers achieve and
maintain speeds as high as 130 km/in
across open terrain. Training Army
drivers to meet this challenge will
require fundamental improvements in
driving simulators (Box 5-5~.
Committee members discussed the possibilities for training vehicle drivers with
test engineers at WES, who noted that experienced professional drivers can achieve
much higher cross-country speeds than soldiers who have not been adequately trained.
Training simulators that would train soldiers to function effectively at high speeds would
have to have very high fidelity and include the harsh motion cues encountered during
high-speed cross-country maneuvers. Systematic testing and evaluation with advanced
motion-based simulators could be used to determine the level of fidelity of simulator
motion cues in a training simulator for AAN applications. The M&S capabilities
required for this functionality would be derivatives of those required for determining
vehicle system trade-offs and defining logistics requirements. However, none of these
capabilities exist today.
The development of M&S technology for driver training simulators should be
integrated with the development of vehicle systems. Driver training simulators would be
effective tools for assessing human factors, optimizing training simulations, and
assisting in development of vehicle system designs. Training simulators could also be
integrated into a DIS environment for operational testing and evaluation. This would
83
BOX 5-5 Vehicle Motion Simulators
Test drivers are capable of much higher
cross-country speeds than soldiers in the
same vehicles because:
· soldiers are not permitted to train at
speeds that would damage vehicles
· motion cues are essential for training
soldiers to achieve high vehicle
speeds
High fidelity models for training soldier
drivers:
. are developed with trade-off analysis
models
· will require computational advances
to run in real-time training
simulators
Simulators to meet AAN speed objec-
tives:
· will use tests and existing simulators
to determine required motion cues.
· should be built for use during design
and system trade-off analyses
. . ~ . . . . . . . . . . . · . .. . . · · · .
require that a tralnmg simulator be cleveloped prior to the actual venlcle system.
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REDUCING THE LOGISTICS BURDEN FOR THE ARMY AFTER NEXT
SCIENCE AND TECHNOLOGY INITIATIVES TO
REDUCE MOBILITY LOGISTICS BURDENS
Based on the preceding analysis of the logistics burdens associated with mobility
requirements for AAN-style operations and the technological opportunities for reducing
these burdens, the committee concluded that the Army should pursue the following areas
of research and technology development. The order of the numbered items under a
heading reflects a rough order of priority.
Operational Mobility
Air Mobility Alternatives. The committee is not optimistic that the Army's current or
planned aircraft programs will provide the operational mobility necessary for AAN
missions. The R&D risks in this area are high, and the acquisition costs may be
prohibitive. In addition, even if the R&D objectives are realized, the resulting aircraft
will add significantly to overall logistics demand for the AAN battle force mission.
Nonconventional, novel concepts for air mobility, however, might lead to a
revolutionary breakthrough. The WIG concept is one example of an approach that seems
to warrant a careful and open-minded evaluation. Although WIG technology has been
demonstrated to some extent, both fundamental research on the aerodynamic principles
and thorough feasibility studies would be essential before the Army could make a
commitment to technology development. A similar combination of foundational research
and exploratory testing for feasibility in military operations would apply to other novel
air mobility concepts. The search for new approaches to air mobility should be a joint
effort; at the same time, the Army must ensure that Army requirements are fully met in
the process. (This initiative pertains to reducing logistics demand for the operational
mobility requirements for the AAN battle force. Obviously, the battle force will also
have a continuing need for a limited number of aircraft for combat and support missions
the battle area.)
Tactical Ground Mobility
1. Mobility M&S Environment for System Design and Trade-off Analyses.
Decisions regarding vehicles will be critical to determining AAN logistics needs. These
decisions must be made from a total systems perspective. The choice of fuel, for
example, cannot be made without considering the vehicle power plant. The choice of
vehicle power plant cannot be made without careful consideration of the vehicle duty
cycle. The choice of power plant may also determine the main gun; conversely, the
choice of the main gun may influence the choice of power plant.
The development of a family of vehicles that weigh 15 tons or less is not only
feasible but also desirable for meeting AAN operational goals. The technologies for an
advanced wheeled vehicle can be developed in the near term because many of them have
already been implemented and could be integrated into a total system with relative ease.
Unfortunately, the current vehicle mobility models (the NRMM) are inadequate
to assess the performance and logistics benefits of active suspension and traction control,
electric drive power trains, or other advanced subsystem technologies. These models
cannot simulate cross-country speeds as high as 130 km/in, certainly not 200 km/in. They
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OPERATIONAL AND TACTICAL MOBILITY
85
cannot be used to optimize route planning for both speed and fuel conservation.
Therefore, the NRMM is only a starting point for the development of AAN mobility
concepts. The Anny should support updates and extensions of the NRMM for the kinds
of design and trade-off studies discussed in this chapter and in Chapter 3.
Developments in M&S technology that would support off-road mobility
analyses are listed below:
.
· traction models for high-speed vehicles on soft soils that can represent the
effects of prior vehicle action on soil and the interaction of tires or tracks with
the soil and can incorporate soil characteristics, terrain geometry, and cultural
features
enhanced NDMM with an updated VEHDYN simulation subsystem
high-fidelity, real-time motion simulators for hardware-and-soldier-in-the-Ioop
simulations that can be used as virtual proving grounds for advanced vehicle
technologies and design concepts, as well as for modeling human-vehicle
interactions and for driver training
· air mobility models, integrated with next-generation mobility analysis software,
to analyze the in-theater mobility of an AAN battle force
M&S capability for fuel consumption that accounts for energy dissipation at the
tire or track interface with soil, for vehicle interaction with cultural terrain
features, and for assessing candidate technologies and design concepts for AAN
vehicles
2. Technology Development to Support a 15-Ton Wheeled Combat Vehicle. In
contrast to the aircraft program, major improvements in ground vehicle mobility are
possible and not excessively challenging. The committee considers a number of
advanced technologies and design concepts to be well within the realm of near-term
development. Use of these technologies would enable the expanded use of wheeled
vehicles for AAN, achieve the principal AAN objectives, and enable meaningful
logistics trade-offs during system design. The committee recommends that a research
and development program be established to demonstrate these capabilities within a five-
year period.
TARDEC and WES are currently doing some research in ground mobility;
however, the Army has not placed a high priority on developing a wheeled vehicle, and
the WES program has suffered from lack of financial support.
3. Look-Ahead Sensor Systems to Increase Vision-Controlled Speed. Sensors for
cross-country mobility have enormous potential and little technical risk. A program in
this area would require the resources and cooperation of WES, TARDEC, the Corps of
Engineers Topographic Laboratory, and perhaps others.
4. Reducing Crew Size through the Evolution of Automated Systems Technologies.
Fully autonomous ground vehicles will be important for performing specialized
functions, but UGVs will not replace crewed vehicles and will not lessen the logistics
burden. In the Tong term, as automated subsystems are incorporated into manned
systems, UGVs may become a component of platoon-like fighting units, in which fewer
vehicles will require human operators. The UGVTEE Demo Ill programs previously
discussed appear to be worth pursuing for the specialized capabilities it could offer an
AAN battle force, although logistics burdens may not be immediately reduced.
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REDUCING THE LOGISTICS BURDEN FOR THE WAFTER NEXT
5. Mission Rehearsal Extensions to Mobility M&S Tools. Mission rehearsal mobility
analyses will be essential for tactical planning and for determining logistics support
requirements. A mission rehearsal capability based on mobility M&S tools can be
helpful for designing supportable vehicles, forecasting fuel requirements for AAN
operations, and minimizing mission logistics.
6. Driver Training Extensions to Mobility M&S Tools. The high-fidelity models and
simulators required to train drivers without risk to them or their vehicles could be
developed along with M&S simulators for mobility trade-off analyses. However, running
training simulators in real time will require computational advancements.
Representative terms from entire chapter:
tactical mobility
