Hi-Fidelity Motion Simulation Development Kit

[Terry214]

I would like to see at least +\- 20 degrees pitch and payload somewhere around 1000lbs.

Grant

Another request for the increased payload of around 1000lbs to 1500lbs if possible. I am working on building a 2 seater cockpit. I weigh 235lbs and I estimate that my cockpit weighs 500+lbs. Factor in the second person(co pilot) then the total weight of the sim cockpit is getting close to 1000+lbs.

Your DIY kit is exactly what I am looking for... thanks for posting your information. Hopefully the increased payload requests can be met.

Terry

[Roland]

40 degrees of pitch is not a big challenge with a longer stroke actuator. (Which we have.)

The 1000 pound payload is doable with the system, the bearings are not the issue however, it is the moment of inertia created from rotating 1000 pounds. No doubt, the way the system is designed, the control system could actuate this amount of weight quickly but upon stopping and going the opposite direction, from a performance standpoint, that I would emphasize as the challenge.

Something to analyze and test - and we will - thanks again for the feedback!

Sean,

Up to now I have not found any need for very fast pitch movements. Take-off acceleration and braking de-celleration all need some low-pass to minimize the false cue due to the rotation needed to achieve the desired tilt angle. So pitch should be relatively easy on the actuators.

Roll is slightly different: Similar to pitch, the lateral accelerations on during turns on ground need some low pass to avoid false cues.
In the air, the small lateral turbulence acceleration can be ported into the roll angle unfiltered: since most of your body sits higher than the rotation piont, fast roll pulses actually feel like lateral movement, quite convincing. These are small excursions though, so again not too much of a burden to the actuators. Touchdown is another fast movement that can be ported directly to roll angle. I found that platform pitch is not required for touchdown effects.

So only 2DoF power platform requirements are not that bad for most airplanes in normal flying conditions. Ofcourse weight unbalance may add to the steady state power consumption. I think the weight distribution is easily the most important factor in the whole design, and should be pointed out clearly to the user. Bigger payload should be possible, as long as they are properly balanced.

Heave is an entirely different matter, where my balanced 160kg system @ 0.5G heave easily consumes 2kW peak power during turbulence.

[smacdon2112]

Up to now I have not found any need for very fast pitch movements. Take-off acceleration and braking de-celleration all need some low-pass to minimize the false cue due to the rotation needed to achieve the desired tilt angle. So pitch should be relatively easy on the actuators.

First off, thanks Roland for all of the inputs - very helpful insight. I concur with your assessment here and might caveat with the type of aircraft. Anything in the combat arena probably requires a little more consideration for speed and direction changes in pitch rotations.

Roll is slightly different: Similar to pitch, the lateral accelerations on during turns on ground need some low pass to avoid false cues.
In the air, the small lateral turbulence acceleration can be ported into the roll angle unfiltered: since most of your body sits higher than the rotation piont, fast roll pulses actually feel like lateral movement, quite convincing. These are small excursions though, so again not too much of a burden to the actuators. Touchdown is another fast movement that can be ported directly to roll angle. I found that platform pitch is not required for touchdown effects.

Interesting take. We will experiment.

So only 2DoF power platform requirements are not that bad for most airplanes in normal flying conditions. Ofcourse weight unbalance may add to the steady state power consumption. I think the weight distribution is easily the most important factor in the whole design, and should be pointed out clearly to the user. Bigger payload should be possible, as long as they are properly balanced.

Couldn't agree more Roland. The challenges of multi-occupant systems though will require much more analysis for balancing on the part of the sim user.

Heave is an entirely different matter, where my balanced 160kg system @ 0.5G heave easily consumes 2kW peak power during turbulence.

Power requirements to physically move a mass is a big drawback, no doubt. There are safety and performance concerns here as well from our perspective: Lots of force required.

[IanH1960]

Roll is slightly different: Similar to pitch, the lateral accelerations on during turns on ground need some low pass to avoid false cues.
In the air, the small lateral turbulence acceleration can be ported into the roll angle unfiltered: since most of your body sits higher than the rotation piont, fast roll pulses actually feel like lateral movement, quite convincing.

Hi Roland,

I started playing with a version of the driver that combined both a low pass slow roll component to cue sustained lateral accels and high pass fast roll impulse to cue lateral impulses at the same time... Didn't finish it though. I wasn't sure about the physical movement "interface" between the two and how it would feel and was distracted by some other work - might be worth digging it back out again as it might be tunable to squeeze a bit more out of a 3DOF machine. Might be worth investigating Sean, would add a new take to the conventional cue algorithms.

Agree with your comments on pitch rate Roland - very easy when cueing fwd accel to introduce a feeling of pitch rotation when it just shouldn't be there - basic problem with gravity alignment cueing.

As a further take on heave cue I think I'm coming to the opinion that because trying to cue sustained heave G's is quite difficult (reduces to a rather unconvincing onset/offset impulse) that a platform with a fairly short heave travel to cue the higher frequency heave effects might not loose much in the end - ie good enough to engender an ongoing sense of vertical motion, and sufficient to deal with bumps and rumbles and general turbulence related bobbing about..

... shorter heave stroke would be easier to build than longer, but I'm not sure by how much. Perhaps an "enhanced" stroke seat tactile transducer might in the end be a good and cheaper compromise to get acceptable vertical motion effects without the expense and difficulty of a full heave DOF.

Ian