Keeping Yaw after all?

Moving to belts and dropping rotation might not be inevitable after all. Instead we could incorporate a system that adds rotation too

The simple pitch and roll solution with belts looks like this :

Screenshot 2014-08-05 13.16.06

This is the view from the bottom of the sphere, motors on the sides and the belts are the blue lines.

Instead, if we have motors that are off the axis but aligned they could not only pitch the sphere but depending on how much each side pulls, rotate it as well.

Screenshot 2014-08-05 13.21.41

Belts are blue and green here.

As I was drawing it I realised a similar system already exists, albeit not in this field. It’s used in some 3D printers and could be adapted to fit our needs here. It wouldn’t give us full rotation, I guestimate only 90 degrees yaw and I’ll have to figure out how to avoid interference with the belts but it’s an idea worth considering.

Check out CoreXY to read about Cartesian Motion to your hearts content 🙂

Interesting link

I found a video that displays a very similar idea to the Feel Three, albeit not fully realised.

Seems they came up with the idea in 2009 but doesn’t look like they followed it though. Their use of air to lift the platform, like playing air hockey, is quite nice since it means the skin can be relatively weak as the load is spread over a large area. However the airpump is quite noisy and the system would need to stay airtight for it to work. Using strong rotational wheels is a cheaper, simpler solution.

The problem with the competition

With these motion simulators they’re generally solving the same problem with two solutions.

The problem is moving the platform, ie you, in at least 2 degrees of motion quickly and a fairly large distance. However, every single solution relies on  basic premise that hasn’t changed since flight simulators were invented : they lift the platform. This means the motors must be expensive and use a lot of power since if someone weighs 100kg, even a 3dof platform needs to lift 33kg each and if you require a large amount of motion the power requirements are huge.

That is why this platform cost $10k, the motors were $5000 for six and the control unit was $2500.

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Some prefer to balance the platform on a spring which reduced the power needed but we still have a small range of motion and this can be quite jerky.

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