A matter of balance

The lack of recent blog posts doesn’t mean this project has at all slowed down, far from it, but we’re far to busy to add much in the way of updates. The last couple of weeks have been crazily busy.

Some of you may have noticed the more realistic design of the chair mount. The one that was in use for the longest time was only ever a place-holder and not at all practical, but this has changed the look of the sphere quite a lot.

The design was always built around the principle that if the main mass was kept in the centre of the sphere it would be easy (and cheap, mechanically and ‘componently’) to impart movement to the user. So ideally you would put the ‘belly button’ of the user in the centre of the sphere, and then it’s quick to move them.

With the new design it should be pretty easy to accomplish this, but the aesthetics are changed quite a lot, especially with the ‘entry level’ 16 panel configuration. With limited panels it now looks like the chair mount is floating strangely in the centre of the sphere. This puts the users centre of gravity in the right place, but might put some people off. It also might make the simulator somewhat challenging to get into for some people.

16 SideView

The rods to mount the chair should be highly adjustable but moving the chair down into the sphere means the motors now how to work harder and the sphere is no longer as safe as it was…. Keeping a balanced COG is vital.

Dropping the chair down makes everything nicer… but the balance is now gone.

16 SideViewLow2

Moving the centre of gravity isn’t an impossible decision to make though, but does need to be adjusted for. With the configuration above the COG has moved down and back… so how can we move it back to the centre of sphere?

Well, we could potentially reintroduce an early design idea and put in a ‘roll cage’. It should never be needed for this but would give some reassurance of safety for the user, and if we need a bar over the sphere for cable management this can now be re-purposed for ‘gravity control’.

16 SideViewLow -XS COG

By adding two parallel bars over the user we can now really quickly adjust the centre of gravity by moving some attached weights. This would also mean it’s really easy to change the set up for different people who want to use the sim. We also have a handy bar to use for support as the user is getting in and out of the seat.

This sadly doesn’t come for ‘free’ since there in an increase in mass and inertia so the movement would be reduced, but this is a reasonably viable option for some people. As always, it would come down to the users choice, if you want a slower sim that is easy to get into and share, add some bars.