ETC Tactical Fighting Systems

G-Pointing: Articulated Centrifuge for Real-Time G Flight Simulation

ATfsadminPhoenix — Wed, 11 Apr 2012 06:30:34 +0000

Authentic Tactical Fighting System: A Revolutionary Flight Simulator For Tactical Flight Training

ATfsadminPhoenix — Mon, 09 Apr 2012 09:12:10 +0000

Introduction
Usually owned by military organizations, Human Centrifuges are typically used for G training in the aerospace physiology departments and for evaluating prospective fighter pilots for high G flight in fighter aircraft. More complex high-fidelity flight simulators installed on a high performance motion system (centrifuge) are used for advanced pilot and tactical flight training. One such revolutionary flight simulator is the ATFS-400™ Phoenix™.

The Authentic Tactical Fighting System (ATFS)-400 PHOENIX
The ATFS-400 PHOENIX is a high fidelity, interchangeable, tactical aircraft cockpit that is integrated with a state-of-the-art high performance “flyable” motion system. Its modular design enables it to realistically simulate the cockpit, dynamic performance, mission systems and interactive elements of a specific type and model aircraft in a specific tactical environment. The ATFS-400 realistically models real world aircraft and threat dynamics. Pilot inputs are processed by the ATFS-400 aircraft specific aeromodel to simultaneously drive the virtual (sight and sound) cues and command the multi-axis high performance motion system to correctly produce the correct inertial G forces. ATFS-400 replicates the flight dynamics providing both the virtual cues and physical stresses, providing the physiological stresses and sustained G forces experienced during combat maneuvers.

ATFS-400 Model 25 PHOENIX Performance Capabilities

Maximum Sustained Gz: up to +15 Gz / -4 Gz
Sustained Gx: +6 Gx
Gz onset (G/s): up to 10 G/sec

A New Approach to Flight Simulation

ATfsadminPhoenix — Mon, 09 Apr 2012 08:54:41 +0000

Co-Authored by: Hal M. Hornburg, General USAF (Ret); Michael D. Malone, Vice
Admiral USN (Ret); and Major General (Dr.) George K. Anderson, USAF, MC (Ret)

Introduction
The military services are expected to endure huge budget cuts and are looking for new efficiencies and innovative ways to save money. If objectively evaluated and tested, realistic tactical flight simulation using a high performance motion system that provides sustained G motion could prove to be a key new capability. As one element of an advanced flight training program, a flight simulator that flies just like a fighter aircraft including realistic motion offers better training at lower cost. In the paragraphs that follow three respected military officers, all retired and experienced in aviation, physiology and training, offer their insights in their own words.

General Hal M. Hornburg, USAF (Ret) served as Commander, Air Combat Command. He is a Command Pilot with over 4400 flight hours in: T-37, T-38, O-1, O-2, OV-10, F100, F-4D/E, F-15A/C/E, F-16C, KC-10, C-21 and T-6 Texan II.

I have flown flight simulators since 1968, and with more than four decades of hands-on experience, I have seen lots of changes, mostly for the good. Until recently, the highest fidelity simulation was only possible for larger airframes due to the inability to introduce realistic motion and G forces into fighter-type simulators. That limitation no longer exists. Follow me on a trip down Memory Lane.

My first “sim” experience was in a T-37 trainer. We called it a simulator but now know it as a procedural trainer. It remained stable, always at 1G, and allowed the trainee to watch instruments change based on power, pitch and bank. The “advanced” T-38 simulator was more of the same, but the airspeed indicator moved more quickly! Later, in the F-4 simulator, not much, if anything, had advanced. Finally, in the F-15 simulator, there was limited motion which provided transient motion cues to represent the appearance of movement, but it did not provide sustained G motion to accurately replicate the simulated aircraft movement. Most of the time, the motion was turned off due to a malfunction in one of the motion axes. The F-16 simulator? More of the same. The simulation community had introduced “part task trainers” into the family of simulation, but true replication of the flight environment didn’t exist.

In these trainers, we were able to learn instrument procedures, practice “switchology”, accomplish checklist items and get a good workout in emergency procedures. What we could not do was do what we did in the airplane. An intercept was “procedures only”. Since we couldn’t see the ground, we could not practice air-to-ground gunnery; and since we couldn’t see another airplane, air-to-air training was non-existent, except for conditions simulating night/weather.

My first experience in a real flight simulator was in the KC-10, with similar experiences in the B-2 and C-17. These simulators, like those used by the airlines, were actually like the airplanes they simulated. Some might be surprised to learn that when USAF pilots learn to fly a large plane, they learn almost exclusively in the flight simulator; then get one or two rides in the real plane, followed by their check ride. What a savings in flying dollars, airframe life and overall wear and tear on the aircraft. By contrast, simulators only play an adjunct role in fighter pilot training and most training is done in the aircraft. Why the difference?

Until very recently, introducing motion into flight simulators was counterproductive. It’s well known that no motion is better than bad motion. It’s unrealistic and only serves to detract from the training environment, which is why motion in flight simulators was forgone for greatly improved visuals and eventually linking in a DMO environment. However, recent breakthroughs in centrifuge technology have finally allowed for the right motion, with high fidelity, to be available today in a high performance motion system. Today’s realistic motion is superior to all previous concepts and has afforded an opportunity to inject
realism into tactical flight simulation. So what’s the problem? It’s that the centrifuge has been the pilot’s enemy since the early 1990’s. The USAF was losing so many planes to G induced loss of consciousness (GLOC) that it mandated all pilots flying fighters go to Holloman AFB, NM for “G Awareness Training”. The problem was that if you didn’t pass this training, you had a great opportunity to lose your wings, or at the least your fighter aircraft assignment. The program wasn’t designed to be punitive, but pilots soon learned that a bad experience at Holloman could have lasting, adverse effects on one’s career. Most pilots would much rather have had a tooth pulled without Novocain than take a spin in a centrifuge.

G-Pointing: Articulated Centrifuge for Real-Time G Flight Simulation

ATfsadminPhoenix — Mon, 09 Apr 2012 08:47:54 +0000

Advances in flight simulator performance fidelity, structural and mechanical design techniques and aerospace physiology research have enabled the development of a new generation of flight simulator technology. Through the integration of a planetary motion centrifuge with a gimbaled, flyable, cockpit module this new class of motion base is capable of replicating G forces identical to those experienced in flight. Predicted flight accelerations are calculated and motors actuate the gimbal system that can be rotated in pitch and roll to align the cockpit through a G field created by the centrifuge. The effect of this software-hardware system is to constantly align the G-vector at the pilot’s seat to the expected direction in flight.

These devices have come to be known as Continuous G Devices (CGDs). Both the basic control system architecture and structural components of CGDs incorporate characteristics of heavy machinery and aircraft design thus providing complex hurdles that bridge several disciplines and require a synergy of techniques to converge on an acceptable solution. Issues such as transport lag, dynamic response and physiological excitation are some of the elements that are inter-dependent as they relate to the simulated effects of aircraft, man and simulator motion base. Solving these problems has been an evolutionary process but one with numerous benefits. The potential presented by CGDs challenges the traditional theory that fully recreating the tactical or upset flight environment is not possible on the ground.

Legacy devices that are currently in service with military and commercial training organizations are only capable of generating transient motions or no motion but are accepted as current simulator technology. As a result, the focus of simulator improvement over the last 40 years has been confined to the cockpit and visual display, which all relate to the pilot cognitive challenges. However, the physiological challenges of flight have largely been ignored. Transient motions and visual stimuli do not impose the physiological stresses that the actual flight environment imposes on a pilot. Motion simulation has traditionally suffered from lack of motion fidelity, technology limitations and associated high operation and maintenance costs. For these reasons, most military organizations have chosen fixed base simulators for tactical aircraft training. CGD’s, on the other hand, provide the capability to accurately generate the physiological responses associated with the tactical flight environment, resulting in an improved level of training fidelity that has not been previously available on the ground.

The result is less expensive and safer training of critical pilot skills in a realistic environment. CGDs have already seen practical implementation and demonstrated successful transfer of skill acquisition in several areas of pilot training. This paper discusses the mechanical hardware behind CGDs in addition to physiological factors involved in both hardware and software design. It further explains the integration of flight simulation architecture into the motion of the device. Rudimentary parameters are examined for accuracy in CGD flight simulation. Additionally, practical evaluations of tactical aviation, commercial aircraft upset prevention and recovery to sub-orbital and orbital space flight are presented. Further comparisons are made between simulator performance and current regulatory requirements for legacy devices where applicable. Finally a synopsis of research demonstrating the performance of these devices is presented.

Simulator Sickness

ATfsadminPhoenix — Mon, 09 Apr 2012 08:44:40 +0000

Symptoms
Both simulators and Virtual Environments can cause different types of sickness or other physical problems. These can include visuomotor dysfunctions (eyestrain, blurred vision, difficulty in focusing), mental disorientation (difficulty in concentrating, confusion, apathy), and nausea including vomiting. Other symptom may include drowsiness, fatigue, eyestrain, and headache. 20% to 40% of fighter pilots suffer from these symptoms when using simulators and the symptoms may last for several hours. It should be noted that fighter pilots are specially selected for resistance to motion sickness and are used to simulators.

Causes
There are two necessities for simulator sickness: a functioning vestibular system (the set of canals, tubes, etc. in the inner ear that gives us a sense of orientation and acceleration) and a sense of motion. There is no definitive explanation for simulator motion sickness but one idea is that it arises from a mismatch between visual motion cues and physical ones, as perceived by the vestibular system. This can happen when there are no physical motion cues (no motion platform is used) or the physical and visual cues are not synchronized. In VE systems, simulator sickness occurs both in motion based systems, e.g. a game pod, and in physically static systems. One hypothesis as to why this occurs is these inconsistent perceptions are similar to what occurs when poison is ingested and we evolved to vomit and get rid of the poison.

Studies have found that the following are more likely to cause sickness:

bright images rather than dim (night time) ones,
wide fields of view
CRT systems rather than dome projection systems
and in motion systems, motion at 0.2 hz is particularly nauscogenic.

The following suggestions for VE are based on suggestions for pilots in simulators:

don’t suggest to users they will get sick or let them see someone else getting sick (it’s contagious)
don’t get into a VE if you are hung over or have an upset stomach
Adaptation is a good fix – do VE every day
don’t do the real thing the same day you do it in a VE
get set before turning the VE on
try low light intensity, e.g. night flying
don’t roll or pitch too much
don’t move your head too much
turn off the VE before getting out

Research is still being done on this to determine the effect of inadequate resolution, latency, and frame rate. HMD’s seem to be the worst, and BOOM mounted displays are not as bad and CAVE users seem not be affected

Authentic Tactical Fighting System (ATFS-400) Signature Technology Description

ATfsadminPhoenix — Mon, 09 Apr 2012 08:29:23 +0000

Every man-controlled vehicle has a frequency “signature” (e.g., a sports car performs and feels very differently from a luxury sedan, likewise with high performance aircraft). In the case of high performance aircraft, the motion and performance signature is sensed by pilots and the previously learned skills used to fly the aircraft are based on their experience with that vehicle’s motion and performance signature. These sensing cues are critical for fighter pilots who make split second decisions and respond rapidly based on their perception of what the aircraft is doing. Accordingly, they must be faithfully replicated in any ground based training device or simulator for a realistic training experience.

A vehicle’s “signature” or feel is determined by the vehicle’s natural frequency and system bandwidth. Natural frequency is a function of the stiffness and mass of the system, i.e., the higher the stiffness, the higher the natural frequency; and the higher the mass, the lower the natural frequency. A vehicle can have multiple resonant frequencies, although it is common to quote only the lowest frequency as the vehicle’s resonant frequency. System bandwidth quantifies how well a vehicle, or a single controlled axis of a vehicle, is able to produce the commanded motions. A vehicle with a higher bandwidth will have a faster response and therefore be able to react more quickly to a changing command signal than a vehicle with a lower bandwidth.

How then can a flight simulator be designed to closely match the signature of a high performance aircraft? This paper presents a solution to this challenge: ATFS-400 Signature Technology.

The ATFS-400 integrates high fidelity flight simulator with a high performance ”flyable” motion-based system that can produce from -8Gz to + 15Gz, 0 to +/-6 Gy, and +/-8 Gx sustained accelerations at mean onsets of up to 10 G/s. The ATFS-400 generates the variable G onset/offset rates and G forces of a tactical fighter aircraft to give pilots the most realistic training experience short of actually flying the aircraft. The ATFS-400 includes ETC’s proprietary technologies of G-Pointing™ and Signature Technology™, interchangeable aircraft specific Cockpit Modules, Wide Field of View visuals, and the Virtual Battlespace to support full fidelity air combat training.

ETC designs the ATFS-400 structures in the Frequency Domain to be stiff and lightweight in order to develop a system that is quick and responsive with high system bandwidth frequency and natural frequency. A structure that is designed with the intent of simply withstanding the forces to which it will be subjected will have a lower stiffness (and associated natural frequency) than a structure which is designed with stiffness from the beginning. Conversely, if a system is designed with a goal of being stiff and lightweight, it will easily pass the stress-strain failure criteria. A high system bandwidth gives a device a wider range of motion capabilities, i.e., the ability to reproduce a wider range of motion profiles and a faster response time, which reduces uncontrollable large-amplitude vibrations.

Over the past 15 years, ETC has designed the ATFS-400 to optimize natural frequency and system bandwidth to produce a sustained G flight simulator that can replicate the performance and “real feel” signature of 4th and 5th generation fighter aircraft. This design combined with state of the art control system architecture, motion control laws and aircraft flight models yields a flight motion platform that can provide the performance and feel of an intended aircraft. Mechanical system resonances are managed to achieve a specific bandwidth by establishing mass and stiffness criteria for all components in the drive train and motion axes.

Accordingly, the ATFS-400 can faithfully replicate the motion and performance signature of a specific type/model tactical aircraft. This characteristic is especially important for high fidelity tactical flight simulation. Pilots can therefore perform high fidelity training in the ATFS-400 with maximum transfer of skills to the aircraft and without negative training.
Signature Technology is more than just high natural frequencies and bandwidth. But it is the unique technology, which contributes to the ATFS-400 replicating the performance and feel of a tactical aircraft and allows pilots to fly the ATFS-400 just like a tactical aircraft. The result is an experience that rivals flying an actual aircraft.

Adaptation to Coriolis-Inducing Head Movements in a Sustained-G High Performance Flight Simulator

ATfsadminPhoenix — Mon, 09 Apr 2012 08:27:32 +0000

Michael Newman a*, Geff McCarthy a, Scott Glaser b, Frederick Bonato c, Andrea Bubka c
a National Aerospace Training and Research Center, Southampton PA, USA
b The Defiant Company, Rosamond CA, USA
c Human Perception and Performance Lab, Saint Peter’s College, Jersey City NJ, USA
* Corresponding author: Michael Newman, NASTAR Center, 125 James Way, Southampton PA, 18966, USA. Tel.: +1 213 355 9100 ext. 1116; Email: mnewman@nastarcenter.com

ABSTRACT
The goal of the present experiment is to investigate and quantify cognitive and physiological adaptation to head movements made in a sustained-G high performance flight simulator. Sustained-G simulators combine long arm centrifugation with high fidelity, gimbaled, flyable cockpit modules to mimic the physiological stresses and G forces experienced during actual tactical flight. In order to properly reproduce these forces, high rotational rates up to 200°/sec of the centrifuge arm are required. A head movement made about an axis other than that of the planetary arm will produce an instantaneous stimulus to the semi circular canals, about a third axis, that can often be disorienting and nauseogenic.

The resultant perceptual illusion of tiling and tumbling is referred to as the Coriolis or vestibular Cross-Coupling Effect. Because tactical flying is rarely eyes-forward, immobile, head-fixed flying, it is desirable to minimize these unwanted perceptual artifacts within the full range of head and neck motion. In the present study we investigated the effect repeated Coriolis- inducing head movements have on the intensity and nauseogenicity of the resultant perceptual response. Nine acrobatic pilots underwent a 5 day adaptation protocol aboard Environmental Tectonics Corporation’s ATFS-400 sustained-G training device. Pilots made a series of precise head movements to predefined visual targets within the centrifuge gondola (Range: Left-Right ± 90° Up-Down ± 45°) during a sequence of simulated 3G coordinated turning maneuvers. Motion sickness, tumbling intensity, postural imbalance and SSQ (simulator sickness questionnaire) scores were assessed on each of the 5 adaptation days and during a retention test 22 days after the initial centrifuge exposure. Motion sickness scores were shown to rapidly adapt after the first training session. Mean MS intensity ratings on Day 1 were more than 200% greater than those reported on Day 2. Overall, 97% of the total MS reduction that occurred over the adaptation week was retained during testing on Day 22. A statistically significant reduction of SSQ scores (including the nausea and disorientation sub-scores), tumbling intensity and postural imbalance (as measured by the Sharpened Romberg balance test) was also observed during the adaptation week and retention test. With a better understanding of the rate, degree, and retentivity of centrifuge adaptation, a training program will be developed to minimize initial symptoms, extend training durations and optimize the benefits of sustained G flight simulation.

The Anti-G Straining Maneuver

ATfsadminPhoenix — Mon, 09 Apr 2012 08:16:10 +0000

There are two components to the recommended Anti-G Straining Maneuver (AGSM):

1. A continuous and maximum contraction (if necessary) of all skeletal muscles including the arms, legs, chest, and abdominal muscles (and any other muscles if possible). Tensing of the skeletal muscles reduces blood in the G dependent areas of the body and assists in retaining or returning the blood to the thoracic (chest) area, the heart and brain.

2. The respiratory component of the AGSM is repeated at 2.5 – 3.0 second intervals. The purpose of the respiratory component is to counter the downward G force by increasing chest pressure by expanding the lungs. This increased pressure forces blood to flow from the heart to the brain.

The respiratory tract is an open breathing system which starts at the nose and mouth and ends deep in the lungs. The respiratory tract can be completely closed off at several different points. The most effective point is to close the system off at the glottis.

Closing the glottis (which is located behind the “Adam’s Apple”) yields the highest increase of chest pressure. You can find it and close it off by saying the word “Hick.” This should be said following a deep inspiration and forcefully closing the glottis as you say “Hick.” Bear down for 2.5 to 3.0 seconds, and then rapidly exhale by finishing the word “Hick.” This is immediately followed by the next deep inhalation repeating the cycle. The exhalation and inhalation phase should last no more than 0.5 to 1.0 second.

NOTES
1. Do not hold your respiratory straining too long (more than five seconds) since this will prevent the proper returning of blood to the heart and may result in loss of consciousness.

2. Anticipate a rapid-onset, high G exposure whenever possible. The skeletal muscles should be tensed prior to the onset of Gs and coupled with the “Hick” cycle as the increasing of G’ begins. Initiating the AGSM too early can inhibit the body’s natural
cardiovascular reflex responses. Starting the AGSM too late is a difficult situation to make up without reducing the G- stress.

Authentic Carrier Launch and Recovery Simulation

ATfsadminPhoenix — Mon, 09 Apr 2012 08:02:14 +0000

OVERVIEW: ETC has been developing an aircraft carrier launch and recovery capability for their Authentic Tactical Fighting System (ATFS-400 PHOENIX). This includes the accurate replication of +/- Gx, Gy, and Gz forces experienced during carrier flight operations. The skills required to successfully launch from and recover to an aircraft carrier are vital to naval operations. The ability to train in a simulator that can replicate the human factors associated with this dynamic flight challenge is a breakthrough in training that can lead to safer and more cost effective operations. These factors are induced by: first carrier landings for Naval aviators, night operations, operations in adverse weather conditions, and pitching decks. This background paper summarizes the progress of this project.

GOAL: The primary objective of the carrier launch and recovery simulation is to integrate a highly complex set of aviation skills into an authentic tactical fighting system that has the capability to generate the physical forces and realistic virtual environment experienced during an actual carrier launch and recovery. This skill set is one of many required, high risk, repetitive tasks that can currently be accomplished in the ATFS-400 PHOENIX and represents another effective training element that can be conducted in a safe and cost-effective manner. This goal not only optimizes flight training, but also represents an opportunity to reduce stress and strain on fleet aircraft.

THE ATFS-400 PHOENIX: ETC’s Authentic Tactical Fighting System is the company’s fourth generation high-performance centrifuge based motion platform. The ability to provide a three dimensional rotating axis to the gondola allows authentic simulation of the G force vector which is known as G-pointing. The ATFS-400 PHOENIX contains all of the important elements of a high-fidelity system to include: cockpit controls, visual display, vestibular and flight models, continuous motion, and environmental.

The ATFS-400 PHOENIX provides pilots with an authentic replication of the physical stresses experienced during high G flight coupled with a true virtual experience that results in a positive learning environment in a safe and cost-effective manner. The capabilities of the system exceed the G onset and offset rates, positive and negative G limits, and sustained G capabilities of today’s modern tactical aircraft. The ability to exchange cockpit modules in less than one hour provides system flexibility, capacity to accommodate changing training needs, and allows the ability to train in any aircraft type.

Dayton Defense Luncheon

ATfsadminPhoenix — Wed, 04 Apr 2012 07:22:50 +0000

Guest Speaker: Mr. Rob Pollock, Director & Chief Process Officer, SAF/AQXC