I can guess that many teams are at least gonna look into adjustable hoods whether it is pneumatic or motorized. So I am putting this here to give an idea at how my team is looking at doing one. For packaging we went motorized because of the space and length of cylinder needed.
This is a work in progress still and was heavily based off of 254 and their 2016 hood.
it is going to be powered by a single 550 with an interesting gear ratio because I don’t quite know how to do the calculations when the big gear is 350 teeth. The gear ratio is
12-36 GT2 pulley
24-350 for the gear
This looks really cool… Our team is looking into some adjustable hoods too and this really helps. Quick question, how were you planning to machine the rack on the hood?
If you want to approximate the force actuated on the hood, I would just treat it as a straight rack and pinion and calculate the force applied at the gear pitch radius, rather than try to treat it as a torque around the rim of a really big gear.
As far as what that force needs to do… There isn’t much resisting it - compression reactions should get taken up mostly in that set of bolts, as long as everything is tightly machined and stiff? Though I suppose the flywheel is relying on the reaction force that is in line with the rack to get backspin…
The big incentive to a larger reduction would be that your low resolution neo550 encoder could benefit from a shorter “distance per click” for tighter hood angle precision… might be worth starting with that as your metric rather than a desired torque/force output…
Are you worried about the shoulder bolts binding? I would be. We’re thinking and doing something similar, but I would want to put bearings on that sliding surface.
I think you just need to figure out how many teeth there would be on the gear if it was a full circle. You could do this by dividing 360 by the angle of the arc of the gear, then multiplying by the number of teeth on the gear segment.
After you know how many teeth the full gear would have, you can just use that to calculate the gear ratio as it if was a standard gear reduction.
So I was actually looking into this. However I do not know how the calculations work when it’s a let’s say for ease a rack and pinion cause would the last reduction when putting into the job calc be 350 (the size of the gear) or be the amount of teeth engaged
where would you mount said absolute encoder? you would need it to be on the axis of rotation of the hood, but I don’t see any way where that could be possible with this deign.
It would actually be geared off the top. I still have to look at what I’m gonna use but I’m looking at a small gear or pinion that’s gonna run on the gears and give you the rotations that you can use to calculate the amount the gear has moved.
