Aircraft motion stimulates the human body’s visual, vestibular, and tactile sensors. Simulators are used to mimic certain motion conditions within an aircraft, but because a simulator is grounded, complete rotational and translational affects of real flight are illusive. However, due to numerous technological advancements over the past few decades, simulators now are able to imitate quite accurately most flight conditions. The degree and quality of imitation, is determined by the capability of the motion system of the device. For this discussion let’s discuss two types of motion: Transient Motion Cueing and Sustained G Motion.

In six degrees of freedom (6 DoF) simulators, the body reacts at the onset of a profile to the initial acceleration1. The brain responds and adjusts instinctively to this motion cue, countering it and balancing its affects according to our vestibular system’s personal gauge. Simulation combines cues that arouse the Visual, Vestibular, Somatosensory, and Auditory senses. Theoretically, all motion can be simulated in various forms of simulators from the non motion variety right through to higher fidelity 6 DoF devices but nothing can be sustained. Non‐sustained motion is called a Transient Motion Cue. This cueing is suitable training for normal flight conditions in a relatively benign environment such as a commercial airliner on a long haul flight where pitch, yaw and roll are limited.

Transient Motion Cueing is a process by which an impulse is directed but not held. Like the name implies, a Transient Motion Cue is a motion cue which accelerates in a particular direction at a particular velocity, but almost immediately begins to decelerate, albeit more gradually, than it accelerated.

When the directed impulse is coupled with visual cues it fools the human body into believing and responding as if the motion were to continue. Internal physiological systems interpret this continued motion cue, transferring data to the brain. The brain interprets the sensations based upon experience and instinct.

But now the signals to our brain are in conflict—our brain has been cued to believe that it must be prepared for a real motion but that never actually happens. This conflict results in motion sickness or coriolis as the transient motion cue washes out.

To prevent wash out we must “hold” the directed impulse or said another way: “sustain” it. This is called Sustained G Motion. We sustain a force by adding either translational or rotational motion forces to the three linear axis, gx, gy and gz.3 This is accomplished with the use of a centrifuge. The translational or rotational motion forces created in a centrifuge are applied to the pilot as the acceleration begins and then unlike the Transient Motion Cue, the motion created by the centrifuge is sustained as would happen in a real aircraft under extreme conditions. Sensing the accelerations of the centrifuge, the human body’s vestibular; skin; sensational and proprioceptive systems are piqued and sustained. Because the G motion is sustained, our brain is not in conflict and all physiological systems respond as they would in a real flight. Therefore, the resulting Sustained G Motion provides the truest representation of the flight experience.

Sustained G Motion experience is not only important for the highly dynamic flight environments experienced by fighter pilots, but commercial airline pilots as well due to the high number of Loss of Control (LOC) incidents that have occurred. Effective Upset Recovery and Air Combat Training both require ongoing transference of sensational data from the aircraft to the pilot through the aircraft’s rotational forces giving way to the development and intuitive understanding of the x, y and z axes in linear accelerations.

Relating basic principles of physics to sustained G forces, we are reminded that g is the acceleration in this case as it relates to earth. Thus “grounding” our system in earth’s atmosphere, g = G as it relates to the amount of force applied to an object and all of the components that make up this object. Sustaining G’s, however, is more complicated as we consider the make‐up of the human body: bones, circulatory system, muscle and tissue and their associated size, weight and density.The fluid components in particular, offer great challenges for understanding our ability to tolerate G forces. G tolerance is affected by things such as the distribution of blood within the body and its viscosity. It is a combination of these and other considerations that make up a truly valid training environment for a combat fighter. For the commercial pilot, a centrifuge can help prepare him or her for any conditions experienced outside the normal flight envelope5, i.e., equipment failure or poor weather conditions.

Transient Motion Cueing simulation therefore is simply not enough to provide a realistic tactical flight and upset recovery training experience. In a centrifuge, pilots are exposed to sustained G levels beyond the normal level of human exposure (up to 9 G) as they would in an actual aircraft. Pilots learn to consider and conserve their own energy as well as the energy held by the aircraft. A good fighter or strike fighter pilot is taught to intensify his/her G loading capability preparing him/her for the intense physiological effects of pulling and sustaining G’s. And the good fighter pilot knows that flight training without physiological stresses is not flight training. Increased stamina maximizes a tactical pilot’s ability to preserve physical energy for a successful mission.

Tactical flight in Combat Aircraft is very different indeed from flight in Commercial Aircraft. However, both situations have demands for understanding and operating within an extreme flight environment. The commercial pilot’s job is to minimize turbulence, overcome visual distractions and system failures, and limit the effects on passengers and cargo. Unfortunately, LOC events have and continue to remain the number one cause of passenger fatalities6. While the combat ready fighter or strike fighter pilot has an entirely different mission—to outlast his/her opponent in an often hostile and foreign environment—both the commercial and military fighter and strike fighter pilots need a solid understanding of the principles required to survive an environment involving extreme maneuvering. Fortunately, both groups of pilots can now better experience the forces of extreme maneuvering in a safe and controlled environment, one that is realistically reproduced by a sustained G high‐performance motion system. So in the end, there is a time and place for Transient Motion Cueing; however, when it comes to training pilots in extreme maneuvering, a Sustained G High‐Performance Motion system is necessary.

The presentation of these aircraft has greatly expanded the capabilities of flight programs while simultaneously presenting new and sometimes unforeseen flight challenges. The expanded flight envelope and more demanding cockpit workload dictates an increased requirement for a ground based, full motion simulator capable of replicating these new, unique flight conditions.

The Environmental Tectonics Corporation is pleased to present the aeromedical and military training community with the Gyrolab® GL-6000™ Gryphon™ simulator, a comparably behaving, ground based flight simulator that precisely replicates the acceleration envelope of these aircraft in order to conduct research and training to meet the unique flight challenges they present.

MOTION PERFORMANCE CHARACTERISTICS

The most notable capability of the GL-6000 GRYPHON simulator, is state-of-the-art motion capability. Providing the most flexibility and fidelity of any other flight simulator on the market today, it induces 360 degrees of continuous rotation in four axes of motion (planetary rotation, pitch, roll and yaw). Two atypical axes of motion are additionally included, vertical and horizontal translation, both capable of performing in conjunction with the 360 degrees of rotation. The resulting motion platform yields a true six (6) types of motion flight simulation environment – six (6) degrees of freedom. Further, in all axes of motion, at all times, a maximum and sustained G force of ±3Gs is exerted in the Gx, Gz and Gy planes of motion (Ref: Table One). The vertical motion travel envelope is ± 3 feet and the horizontal motion travel envelope is ± 17 feet.

The GL – 6000 GRYPHON flight simulator motion capability affords emulation of the following flight scenarios:

• Vertical Takeoff and Vertical Landing (VTOL)
• Short Takeoff and Landing (STOL)
• Short Takeoff and Vertical Landing (STOVL)
• Translational Lift
• Conversion to Forward Flight and Hover
• Hover (In Ground Effect (IGE) and Out of Ground Effect (OGE))
• Conversion from aircraft flight to a hover
• Dynamic Mission Rehearsal capability for MV-22, CV-22, and F-35B
• Flight phase transition
• Dynamic G tolerance
• Spatial disorientation/spatial orientation
• Situational awareness
• Motion sickness research and desensitization
• Fatigue countermeasures
• Adaptation to unusual acceleration environment training

Research and training communities alike now have the capacity to accomplish two critical objectives. First, it is possible to identify new and sometimes unpredicted in-flight stresses to the aircraft and pilot resulting from the uniqueness of each motion profile. Second, the GL-6000 GRYPHON simulator newly affords a simulated research and test environment providing a forum in which to safely address these concerns and formulate corrective in-flight procedures in a safe, high – fidelity ground-based environment.

Full, sustained G motion further supports G tolerance and G readiness training to achieve, maintain and elevate operational readiness. The motion profile supported by the immersive visual system enhances and increases the acquisition and retention of taught skills. For research purposes, the sustained G motion capability provides a nearly identical flight environment obtainable without the risk and expense of the actual aircraft.

The greatly expanded envelope of capabilities of the GL – 6000 GRYPHON simulator as a research and training device is a technological advancement in simulation. As the first GL – 6000 GRYPHON flight simulators become more widely and actively utilized, additional applications for training and research will be identified, adapted and applied. Ongoing research and development efforts by the Environmental Tectonics Corporation, in conjunction with the international training and research community, will guarantee that subsequent iterations of the GL-6000 GRYPHON simulator will augment its current scope of performance with resultant excellence.

SAFETY

For over 40 years, ETC has been designing, developing and operating human occupied simulation systems for use in training and research applications, in accordance with all applicable international and domestic safety standards as set forth by U.S. and European based organizations such as ASME, ASTM, DIN, etc.

The GL – 6000 GRYPHON simulator, in accordance with these standards and in addition to stringent internal ETC manufacturing standards, including ISO 9000 and various others, has been designed and produced with an overarching, inherent design to be as safe as possible in all applications.

Each GL-6000 GRYPHON simulator is equipped with the following safety devices;

• Independent safety computer
• CBIT
• Embedded diagnostics
• Dual stop controls – (operator & occupant)
• Automated brakes on each axis
• Dynamic electrical braking
• UPS (uninterrupted power supply)
• Watchdog timer
• System & facility interlocks
• Floor emergency egress and trainee extraction door

All of these features have been identified by ETC’s safety team as quintessential for ensuring safety via ETC’s years of experience in building safe, effective devices.

To further support the safety of each simulator, ETC mandates a comprehensive, facility implemented test program consisting of a rigorous battery of safety tests which are executed throughout and at the completion of the production cycle, ensuring the mechanical and electrical soundness of each machine produced.

Finally and most importantly, each simulator that leaves the manufacturing facility has been put through the last and final safety test – man-rating. Man-rating is an integral component of the development and life cycle of each human occupied system produced at ETC. Throughout the man-rating program, the design, safety management and control, flight operations validation, and unit life span are monitored and valuable feedback regarding these aspects of the system are obtained. Data collected is used for program and equipment modifications on an ongoing basis.

VISUAL SYSTEM

The use of a highly immersive visual system is proven to contribute significantly to the occupant’s perception of flight by greatly abating the detection of any motion artifacts potentially interfering with the research or training objective. The GL – 6000 GRYPHON simulator boasts a highly realistic, single visual display system providing each occupant with a realistic, completely immersive visual experience with reduced perception of residual motion artifacts during operation. The collective Field of View (FOV) is 210° Horizontal by 120° Vertical.

Uniquely, the adjustable visual display system possesses the potential for the following fields of view to be accommodated when required;

• 162º x 148º FOV when viewed from 5 inches on-axis
• 114º x 82º FOV when viewed from 20 inches on-axis
• 82º x 52º FOV when viewed from 35 inches on-axis

All visual databases are completely interactive and tailored to meet each individual customers specific training and/or research requirements.

COCKPIT FIDELITY

The GL – 6000 GRYPHON simulator possesses a high fidelity cockpit which may be configured to emulate any aircraft of the Client’s choosing. The physical dimensions of the interior is large enough to accommodate side-by-side seating (such as in the MV-22 and CV-22 aircraft) as well as a single seat or tandem seating configuration. At its largest section, the cockpit interior is approximately 77″ H x 70″ W x 110” L.

Each simulator utilizes a cockpit module concept design whereby the entire cockpit of each is fully extractable and easily exchangeable with another module, enabling the performance of an entirely different set of flight scenarios. With modules that can be interchanged in less than one (1) hour, GL – 6000 GRYPHON simulator users are able to realistically simulate as many different tactical aircraft as there are available Cockpit Modules. When not installed in the GL – 6000 GRYPHON simulator, the Cockpit Module functions as a stand-alone, portable and expeditionary Operational Flight Simulator (OFS) for multiple applications.

Each cockpit module can be data linked to other cockpit modules or full mission simulators for multi-ship training in a distributed mission operation (DMO) environment. This capability greatly enhances the flexibility in a flight program or research initiative. Cockpit modules include an aircraft-specific aeromodel tailored to the specific performance of the type and model of aircraft being simulated.

MEDICAL & RESEARCH DATA ACQUISITION (DAQ) SYSTEM

The GL – 6000 GRYPHON simulator is designed to accommodate a variety of data acquisition systems. It is designed with real-time data acquisition, processing and storage capability local to the unit with high bandwidth communication channels transmitting the data to the operation room. The data acquisition control console is equipped with direct discrete analog and digital signal connections along with various digital bus forms. This transparent and flexible design allows users to integrate any Commercial Off The Shelf (COTS) medical monitoring system or their own custom designed system.

CONCLUSION

The GL – 6000 GRYPHON simulator provides users, both research and training personnel alike, with a flexible, cost effective simulator of unrivaled capability in which to conduct various flight scenarios emulating the most advanced aircraft now on the market today.

With a continuing commitment to technology and excellence in the flight community, ETC is actively pursuing new applications of the Gyrolab GL – 6000 GRYPHON simulator, and invites discussion of new and alternative applications.

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
• Sustained Gz: +12 to +15 Gz / -8 Gz
• Sustained Gx: +6 Gx
• Sustained Gy: +6 Gy
• Gz onset (G/s): 8 -10 G/sec

ATFS-400 Model 31 PHOENIX Performance Capabilities
• Sustained Gz: +20 Gz max / -8 Gz
• Sustained Gx: + 6 Gx
• Sustained Gy: + 6 Gy
• Gz onset (G/s): 10 -15 G/sec

ATFS-400 Model 31 PHOENIX Improvements
• Longer, stiffer, and lighter in weigh arm
o Reduced weight by 17%
o Increased stiffness by 300%
o Reduced Coriolis by 10%
• Direct Main Drive System – the main drive system incorporates a direct drive motor that is coupled to the main shaft in the pedestal assembly. This arrangement allows for smoother accelerations and decelerations.
• Direct Drive Dual Pitch and Roll Gimbal Motors have been incorporated to improve pitch and roll response and to provide a safety backup in the event of a pitch or roll motor failure.
• Wider Field of View Visuals – the projected dome visual display has been increased to a baseline 210°H X 120°V out-the-window view.
• Total System Bandwidth was increased to 4 Hz, which allows the ATFS-400 Model 31 to accurately follow aeromodel commands to replicate the motion and “signature frequency” of the simulated aircraft.

Figure 2. Artist’s rendering of the ATFS-400 Model 31 PHOENIX High Performance Motion System (Human Centrifuge)

The ATFS-400 PHOEINX design integrates five unique proprietary systems developed by Environmental Tectonics Corporation [ETC®] over nearly three decades. These are the high performance human motion platform, aircraft specific and interchangeable Cockpit Modules, G-POINTING® motion control system, Signature Technology™ and Virtual Battlespace. The ATFS-400 combines and integrates these unique technologies into a system with high dynamic bandwidth and low control cycle lag, similar to a fourth or fifth generation tactical aircraft. Precisely matching the physical and virtual response of a specific type and model aircraft creates a simulator experience that closely emulates the actual aircraft experience. The ATFS-400 PHOENIX provides a learning environment with realistic physiological stresses and virtual experiences, and tasks the pilot to master the hands-on skills while coping with tactical environmental stresses. The simulated experience can emulate aircraft performance at the edge of the flight envelope and provide dynamic correspondence for conditions not feasible in current generation simulators.

The G-POINTING motion control system controls the high performance motion system and is the key to the realistic simulation of varying G forces. It is a process whereby the centrifuge gondola that has 360° rotation in pitch, roll and planetary motion is continuously and actively oriented to provide pilots with high fidelity, sustained G levels. Pilot inputs via the control stick are processed through the aircraft specific aeromodel and the control laws of the high performance motion system in order to produce the correct Gx, Gy, and Gz forces.

Over the last 15 years ETC has developed and perfected SIGNATURE TECHNOLOGY and incorporated it into the ATFS-400. Prior to ETC’s ATFS-400 Phoenix high performance motion system there did not exist a motion platform that would replicate the full and accurate motion stimuli of a tactical aircraft. Every man-controlled vehicle has a motion signature (e.g., a sports car performs and has motion characteristics that are very different from a luxury sedan). The vehicle operator senses this motion signature and the previously learned skills he uses to operate that vehicle are based on his experience with that vehicle’s motion and performance signature. This is especially true for fighter pilots who make split second decisions with rapid reactions based on their perception of what the aircraft is doing. ETC has designed the ATFS-400 in the Frequency Domain to produce a sustained G flight simulator with bandwidth similar to 4th and 5th generation fighter aircraft. Today’s high-end cars like the BMW, Corvette and Porsche are designed in the Frequency Domain. Mechanical system resonances are managed to achieve a specific bandwidth by establishing mass and stiffness criteria for all components in the drive train and of each axes. This combined with state of the art control system architecture, control laws and flight models yields a flight motion system that can provide not only the performance of 4th and 5th generation fighter aircraft but also the feel of the specific aircraft. This process, applied throughout the ATFS-400 system, establishes the system bandwidth. The ATFS-400 system bandwidth is equal to (or in some cases exceeds) the tactical fighter aircraft. This system bandwidth allows the ATFS-400 to accept and faithfully execute commands from ETC’s high fidelity aeromodels. Accordingly, the ATFS-400 can faithfully replicate the motion and performance signature of the tactical fighter aircraft simulated.

The Cockpit Module consists of an aircraft-specific, modular cockpit configured with high fidelity controls, realistic displays, a varying wide field-of-view visual display with a minimum of 210°H and up to near 360°H FOV and with a real world visual display. The Cockpit Module can be installed in the gondola of the ATFS-400 PHOENIX or it can function as a stand-alone Operational Flight Simulator (OFS) and be data linked to the ATFS-400 PHOENIX for multi-ship training and to other Full Flight Trainers with High Level Architecture (HLA) or Distributed Information System (DIS) compatibility in a Distributed Mission Operation (DMO) environment. Cockpit Modules include an aircraft-specific aeromodel tailored to the specific performance of the type and model of aircraft being simulated, and are interchangeable in the ATFS-400 PHOENIX gondola in less than one (1) hour, enabling users to realistically simulate as many different tactical aircraft as there are available Cockpit Modules. .

Additionally, the Cockpit Module is networked to a domain–specific Virtual Battlespace that provides the tactical interactions. It sends the type-specific calculated aircraft behavior to the Virtual Battlespace system, exchanging signals with other simulators connected to the Virtual Battlespace in a distributed mission network to maintain a true common tactical situation.

UNIQUE value provided by the ATFS-400 PHOENIX

High fidelity flight simulation offers many benefits, specifically significant cost savings per flight hour versus training in the aircraft. However, only realistic dynamic motion in flight simulation that provides high sustained G flight simulation and realistic physiological stresses of tactical flight can provide unique value in tactical flight simulation. Unique training value provided by the ATFS-400 PHOENIX, which non-motion flight simulations cannot provide, includes: high Angle of Attack (AOA) maneuvering required for managing maneuvering energy, affordable exploration of the edge of the flight envelope for a specific aircraft’s kinematic envelope, departure from controlled flight and spin training, Push-Pull training in a tactical environment, Spatial Disorientation training, G Readiness / G Tolerance training, and expanded pilot performance capability, which greatly contributes to maintaining flight proficiency and enhancing pilot combat readiness. The ATFS-400 PHOENIX is also uniquely capable of providing aviation physiological research in a tactical environment. Bottom line, using the ATFS-400 PHOENIX for tactical flight training eliminates risk in high G training, both initial and refresher, reduces need to use aircraft for high G environment and training and provides the capability to maintain currency for high G tolerance and readiness.

Cost Comparison and Benefits of the ATFS-400 PHOENIX

The ATFS-400 PHOENIX enhances safety and operational readiness, while reducing training costs by a factor of greater than 30:1. Cost benefits include:
• Extended Aircraft and System Service Life
• Extended Engine Service Life
• Reduced Fuel Consumption and Environmental Impact
• Reduced Annual Aircraft Scheduled and Unscheduled Maintenance

Training activities that can be supported by the ATFS-400 PHOENIX (when equipped with an aircraft-specific cockpit module)

• Realistic Air Combat Training
• Basic Fighter Maneuvers
• High Angle of Attack Maneuvering
• Tactical Maneuvering Operations in a Multiple Aircraft environment
• Tactical Engagements across the full Combat Threat environment
• Threat Avoidance and Defensive Air Combat Maneuvering with combat damage
• Interactive Engagement with Weapons Employment and full outcome simulation
• Aircraft Handling with Simulated Combat Damage
• Initial and Refresher G Training
• Spatial Disorientation Training (in the high G environment)
• Situational Awareness in complex multi-threat day/night and all-weather environments
• Unusual Attitude Recovery Training
• Aircraft Mishap Investigation

Additionally, the ATFS-400 PHOENIX can also support a full range of research activities. It has a configurable medical monitoring and data acquisition system that can be tailored to support investigator’s needs for both clinical and operational research.

CONCLUSION

The ATFS-400 PHOENIX provides user’s, both research and training alike, with an affordable, high-fidelity, high sustained G flight simulator in which to conduct high G flight training events, while emulating the performance characteristics and physiological stresses of the most advanced 4th and 5th generation fighter and fast jet aircraft.

With a continuing commitment to technology and excellence in the tactical flight community, ETC remains open and amenable to discussing new and alternative applications of their ATFS-400 PHOENIX.