This will not help with distance because the point of having a compressible material is to increase the time and amount of frisbee in contact with the wheel. If you don’t make the wheel compressible, the frisbee will only touch at that one point where it and the wheel are tangent.
Have you actuallytried a compressible wall?
I believe the fact that you are also storing energy in the frisbee when you compress it can also have an effect on distance.
The problem is, any change you make you have to go through the tweaking process over again, how bad is the ware rate? how many Frisbees can you shoot before having to change the tubing?
cheers
arun
We can get about 50 shots on 1 wheel. We don’t think this is that bad as one of our old prototypes needed to be changed every 2-3. The issue is that it takes to long to go and change our wheel(about 10 minutes which is no good in eliminations). Can anyone think of a material that can act like the tubing but more durable? We are currently thinking of using andymark tread instead . Ill be looking around in Toronto tomorrow for insparation.
one quick change you can make is make the wall flexible - so maybe thin gauge metal only fastened on two points - for a rubber-band effect, replicates to some extent what pneumatics do.
Somthing like:
but with only two hold-downs - the tension follows the Frisbee.
also you can try cutting up the latex and riveting it on - maybe that helps because it will reduce movement of the latex.
cheers
arun
Please also remember ::safety:: safety when you talk about attaching things to wheels that are already spinning beyond what they’re designed for.
a little searching and you can find a pic on CD of what happens when tread separates from a wheel by pulling out of its rivets, but don’t if you have a weak stomach.
Stay far from the plane of the wheel (“plane of death”, “plane of destruction”), and use guards if you’re going to experiment further with (cough) re-inventing the wheel.
Can’t believe this hasn’t been suggested yet, but if you can get these in time…
http://www.andymark.com/product-p/am-0970.htm
Problem solved. Same size, you get the compression you need (even variable to some extent as you can play with the pressure of the wheels), and it should mount on the existing hole pattern of the wheels you’re currently using.
used that wedgetop tread that you can buy from andymark on a 6" performance wheel. we also put that same material on our wall that is 1/8 thick lexan. it seems to work pretty good.
These are what we were going to use originally however one of our mentors mentioned that people have found that by spinning them at the 6000rpm we are that they will explode. This is what made us think of surgical tubing to get similar results. Also those weigh .5lbs heavier than our current wheels and we need as much weight reduced as possible to prevent being overweight. If it weren’t for this problem we would put them on, as we have 2 lying around the shop.
We went through the same issues. Spent big bucks on pneumatic wheels, etc. and ended up using an adhesive non slip rubberized tape on our wheels. Glued it down with industrial strength super glue and it works just fine. We put a small (thin) piece of the same material on the opposite wall. We made it a bit longer than the wheel’s contact space. It too works great. Got the stuff at home depot. The glue is some I use for my wargame miniature construction.
Do you have a link or picture of this material you have put on your wheels? Is it like the non-slip material you put under a rug or more like what you would find on the step of a ladder. This type of solution is exactly what we need we just haven’t found a material yet. How much compression did you have on the Frisbee(if any)? Also what kind of results were you getting; 10ft, 20ft 30ft…?
We are using the pneumatic wheels on our shooter with no problems.
We made two modifications to the wheels to ensure long wheel life:
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We balanced the wheels. We placed two 10-32 x 1.75" long screws in the hub slot opposite the valve stem, held in by foam sticky tape placed into each corner of the slot on the rim side. (Don’t worry, the foam is compressed when the wheel spins up, so they don’t get loose.)
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We added a carved oak block between the valve stem and the rim to keep it from flexing when spun.
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We support the wheel from both ends of the hub with a 3/8" bolt attached to the shooter frame, poking into a bearing pressed into the hub on the side away from the motor.
We can shoot pretty well into the 3 point goal at 50 feet. (Our testing was outdoors during a wind storm, so the average wasn’t that great.)
my opinion: I would be more concerned with tread pulling from rivets or anything else that’s “stuck” onto a wheel pulling apart then the pneumatic tire material breaking.
My (limited) evidence: I still get pretty nervous when seeing the tire “pancake” a bit at higher rpm when it is filled to “a little bit more than flat”, but our 5+ year old tire has never failed. I HAVE experienced andymark tread coming out of rivets twice in 2009 when we were spinning a traction wheel at ~4000 rpm. Also this
Pneumatic tires are designed to spin fast (e.g. on automobiles), while robot wheels are not. They have cords under the tread to hold them together. I’d feel much safer being near a robot with a (properly balanced) pneumatic tire spinning at 6000 RPM than a robot wheel with stuff stuck to it spinning that fast.
Cars have steel belts in the tires. Small tires like wheelbarrow tires do not. Also, car tires don’t spin at 6000 rpm. A typical 15" tire is 25" diameter - giving around 812 r/mile, which is 812 RPM for 60 mph.
Here’s what we bought at Home Depot:
http://www.homedepot.com/p/t/100211722?catalogId=10053&langId=-1&keyword=anti+skid+adhesive+for+ladders&storeId=10051&N=5yc1v&R=100211722#.UTvGdKUTtz8
We aren’t the most scientific when it comes to how much compression? It was trial and error. We’ve made our shooter adjustable at the side wheel and at our top driver motor wheel and did everything by touch, feel and sight. Our Mark II eyeballs did the trick. We used a piece of rubber weatherstripping (after trying several thicknesses) on the wall. We’ve put 2" teflon tape from McMaster-Carr on the shooter “rails”. Compression? Don’t have any. We use an Andymark 6" wheel from 2011 KoP. We’ve constructed several wheel replacements for the tournament. Again, we attached this material to the wheel, custom cut it, and glued it down with gap filling CA.
I spent some bucks on pneumatic wheels but the performance was not optimal. We’re shooting 90-99% at 30’, 80-90% at 40’. We’re using one (1) CIM directly attached to the wheel with an 8mm hub . We’ve got another drive on the top of our shooting mechanism so we get spin from the side and push from the top. It works, is robust and is simple. For our team, simple is good. Not many of my students know how to turn screws but we’re learning every year. We’ve got an acrylic cover over the side wheel for safety’s sake. We’re not fancy, nor do we have a huge bankroll. We try to use KISS principles and keep the costs to a minimum.
Our shooter runs with 1" of disc compression with the pneumatic wheels. Result.
Compression on the wall of the shooter, though, instead of the wheels may be totally different. The compression of the pneumatic wheels help grip the frisbee and throw it better.
Either way, try adding more compression with both a solid material and something compressible on the wall and see what happens.
It is. they are definitely 2 different variables with different effects. Unfortunately, I think a lot of teams are not fully testing the 2 and missing out on some performance choices they could have if they understand the difference.
Nice bot in the video btw!
When you say 1in of compression what do you meen by this. When i think of compression i think about if the gap between the edge of the wheels to the wall is the diameter of the disk(what 11in is that), whatever amount you remove from that is the amount of compression. So compression of .25in on an 11in disk the space measured would be 10.75in. The reason i ask is because the 1in you mension seems an awful lot that the way i consider it.