Motion control technologies that can save lives

Moog has a long history providing hydraulic and all-electric motion bases for flight simulation and remains on the forefront of new technology that is re-energising the industry.

The better the fidelity of the training, the better the chances of survival: today, operational flight accidents in US combat are 80% less than they were 30 years ago due to a commitment to training activity and the increase in simulation fidelity.

And Moog is on the front line of this training, providing state-of-the art motion components and motion bases for flight training.

Moog has a long history providing hydraulic and all-electric motion bases for flight simulation and remains on the forefront of new technology that is re-energising the industry.

The critical nature of the application is clear when you think of the implications training has for pilots and rescue personnel.

When an application means life or death, great consideration is given to the fidelity and reliability of the motion control system.

Simulation training has a broad range of motion requirements.

For flight training, there is a need for large actuators with 1.52m of stroke and nominal output forces up to 15,000kg.

A training cycle can last up to 4 hours with the flight crew and training instructor inside the instructor hut/cockpit assembly.

The cockpit assembly utilises as much of the "real" bird as possible.

Outside of the cockpit is one of several types of visual systems, which projects the appropriate scene to the flight crew.

The motion base has to be capable of moving the hut, cockpit, and visual system.

Smooth operation is mandatory, as is low noise generation.

The system will sit at mid stroke for the majority of the training period, just as the average passenger experiences during a flight on a commercial airline.

However, when the instructor generates a problem, the motion base must respond in any or all six degrees of motion, ie pitch (tilt up or down), heave (up/down), roll (tilt to the left or right), surge (move forward or backwards), sway (side to side) or yaw (rotation to the left or right).

Rapid and violent motion may exist for 1 to 3 minutes and than back to the calm and level flight.

However, even with the straight and level flight, motion is still required to generate engine vibration, flap actuation, pump effects etc.

Driver training has the opposite requirements.

Vehicles (off road, marine, or trains) all have high vibration road and track requirements, whereas marine training requires a reproduction of sea states.

In these cases, the motion base is almost constantly moving, and though response is critical, smoothness is not as critical in driver training.

Moog has been providing components for simulators for over 30 years, first servovalves, than hydraulic actuators (motion legs) and finally complete motion bases.

Today, Moog offers motion bases based on either electrohydraulic or electromechanical technologies.

An example of Moog's motion base products is the all digital electrohydraulic six degrees of freedom motion base with a payload capability of 14,500kg of flying weight recently delivered to NLX Corp, an internationally recognised provider of simulation and training systems for military and commercial customers.

The application is for the US Navy training centre at NAS Whiting for the TH-57 helicopter.

These motion bases represent the integration of Moog's hydraulic background, our capability in system design and integration, and our software development to meet the demands of an industry that requires a 95% or better up time for the complete system (not just the Moog motion base).

A question an industry insider might ask is "Why use an electrohydraulic motion base when the world seems to be converting from electrohydraulic systems to electromechanical systems?".

There is no single answer to this question.

Every site and application is unique to itself.

In large training centres with multiple motion bases, an upgrade of only one base converting to electric would increase the training requirements of the maintenance staff as well as add to the inventory of spare parts.

By staying with a hydraulic system, they reduce their overall capital cost and only have a small training delta.

For some applications, hydraulics is still the only option.

Flight simulators with large flying payload requirements (18,000kg and above) are only addressed with hydraulic components.

For 4500kg to the mid 13,600kg.

of flying load, either solution will address the requirement from a motion side.

The all-digital motion control cabinet represents an industry trend that is replacing analogue signals and processing with digital communication and control loops.

Unlike hydraulics where replacement components (and sometimes the original components) are available in the marketplace, analogue components, if available, are becoming harder to find.

With all upgrades of the host computer, image generators, etc.

utilising today's personal computers with Ethernet or FireWire communication protocols, the service personnel are already receiving digital training.

Thus, the issues of training in digital technology have already been addressed, with the motion base training adding only a small delta.

For loads less than 4500kg, all-electric systems seem to be the general acceptable solution.

Here Moog offers the alternate electromechanical technology and provides complete turnkey solutions for 1000kg payloads (6DOF2000E) and 2500kg payloads (6DOF5000E).

In the intermediate range, Moog's electromechanical systems are similar to the components provided for the hydraulic motion bases.

The all-electric flight simulators include electric legs with integral absolute position feedback transducers, and all digital motion control cabinet.

Moog also provides the upper and lower joints as well as optional instrument packages used to test the system at commissioning and to run ongoing performance tests such as the operational readiness test.

With the data logging features built into the motor controllers and PC, this provides maintenance personnel the ability to test these systems without additional test equipment.

With Moog's unique position of providing high performance servovalves and associated components and electromechanical servo actuators, the company is in a position to offer the technology and performance solution best suited to individual training needs.

From replacing and upgrading hydraulic motion bases for current simulators to building state-of-the-art new electric bases, Moog is a leader in providing motion solutions for the industry.

All together, Moog has delivered over 350 all electric motion bases and thousands of servovalves and other hydraulic components for this important area of high performance motion simulation in military, commercial and industrial training.

Moog is a manufacturer of high performance motion control solutions, providing the "brains" and the "muscle" to address demanding needs.

Moog components and systems used in training and certification of pilots, drivers, and crews highlight this capability.

Regardless of the muscle technology used, our "brains" of motion simulation uses state-of-the-art digital control topologies with Moog's motion control software.

The company's capabilities in electrohydraulic and electromechanical closed-loop systems allows it to address any application, matching the performance and customer desires for specific projects.

Moog uses the same approach whether it is a flight training, industrial automation, or a process control application: apply the right technology based on the need, not just the "production" technology that is "off the shelf".

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