Seeing Really Is Believing (or the “non-Importance” of a motion base)

March 16th, 2022
Full Flight Simulator

Starting with the “Link Trainer” back in 1929, motion has been an important part of simulation to help train pilots to fly airplanes. And that’s why a “Full Flight Simulator” is equipped with a motion base that moves in all directions, to create sufficient realism.

Nonetheless, many years of (military) research has taught us that student pilots who train at a simulator with no motion base do just as well, when they “graduate” to a real airplane, as student pilots who train at a simulator with a motion base [1].

In other words, although the motion base makes the simulated flying “more realistic”, it’s not making the training simulation “more helpful”.

To understand why, remember that we also perceive motion with our eyes. Indeed, what we see, all by itself, can provide the sensation of motion to a surprising degree.

About Vection

“Vection” is the technical term for the “feeling” of movement generated by your visual system [1].

Imagine sitting in a train that’s stopped, watching the train beside you just starting to move.  Of course, you’re not moving (people in the other train are moving), but the cross-sensory cueing nonetheless “makes” you feel movement that’s not actually there.

In fact, science tells us that your eyes can even override your inner ear because after any initial (real) movement, your brain pays particular attention to visual input, and starts to “ignore” vestibular input.

About the Importance of “Seeing Big”

Now it’s easy to see (pun intended) that for vection to “work”, the visual presentation of the simulated world needs to “fill up” your field of view. Indeed, simulation science tells us that 180 degrees side-to-side and at least 40 degrees up/down are required [2].

And that’s why the best training simulators are equipped with multiple displays, typically three placed side-by-side in front of the operator controls, to create a 180 degree forward-looking “panoramic” visual presentation.

In the simplest case, the displays are simply HD “flat screen” TVs that, as we all know, are getting bigger, brighter, and cheaper all the time, helping to make multiple displays more affordable (because of lower prices) and vection more compelling (because of bigger sizes).

About Simulating Trucks (and Heavy Equipment)

As shown in the photograph, the motion base of a “Full Flight Simulator” moves the complete airplane cockpit, with the student pilot and instructor inside. And to do that, it’s very large, electro-hydraulic, expensive to buy, and costly to maintain.

For these reasons, training simulators for trucks, and sometimes heavy equipment, are instead equipped with a small, electric, motion base that moves just your seat, or sometimes the four corners of your seat “platform”.

But because the “big screen” displays placed around your seat don’t move when you move, this “interferes” with the sense of motion created by the motion base.

The fact is, in order to (safely) move displays along with your seat, the displays must be small, but now the presentation of the simulated world no longer “fills up” your field of view. This is especially true when the displays are in “portrait mode”, because seeing more vertically (up/down) means seeing even less horizontally (side-to-side). All that, in turn, makes vection impossible, further limiting the realism of the simulation experience.

Worse, because the motion is not “immersive” when everything moves together as in a Full Flight Simulator, students can quickly succumb to “motion sickness” (sometimes called “simulator sickness”), especially when there is even the smallest time delay (“lag”) between the changes that you see and the movements of the motion base.  And that’s why students can sometimes only spend just a few minutes “at a time” at the simulator which, of course, greatly limits training efficiency. (Alternatively, some instructors just turn off the motion base, so now you’ve paid for something you don’t even use.)

One final note: when you’re first learning to operate heavy equipment, any motion will make learning harder, not easier, because now there’s something “extra” for your brain to take into account, in addition to what you see and hear.

Simlog’s Better Idea: Vibration

Let’s recap: regarding airplanes, simulator-based training research tells us that although having a motion base to create movement makes simulated flying “more realistic”, that motion base doesn’t make the training simulation “more helpful”.

And for trucks and sometimes heavy equipment where motion is not immersive, “motion sickness” is an ongoing “challenge”. Worse, students can be tempted to make the motion base move as much as it can by deliberately “making mistakes”, possibly leading to injury or damage to equipment.

Well at Simlog, we believe that that vibration is the right way to make training simulation “more realistic” without introducing any danger or risk of “motion sickness”, simply by adding something that you feel in the “seat of your pants” at a fraction of the cost of a motion base.  And we have many years of customer success to prove just that.

References

[1] “Military Simulation & Training Magazine, “The Science of Simulation”, June 27, 2019,

https://militarysimulation.training/articles/science-of-simulaton/

[2] B. Jolivalt, “La simulation et ses techniques”, Presses universitaires de France, 1995.