Forum: Technical Discussion
Yesterday, 01:25 PM
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Replies: 18
Views: 1,104
Re: Easy Bumper Switching?
We used these latches last year for our first time and had problems with them latching by the end of the season. The bumper had shifted size a little, so it was hard to get the latches over the...
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Forum: Robot Showcase
10-14-2016, 11:32 PM
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Replies: 14
Views: 2,475
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Forum: Extra Discussion
07-10-2016, 04:12 PM
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Replies: 16
Views: 2,072
Re: pic: GEAR & CHAIN IN TUBE 8WD
Have you run a chain below tube/drive chassis/bellypan like this before? Do you run into issues with getting carpet junk into the chain or having the chain exposed to accidentally being hit on...
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Forum: Robot Showcase
06-16-2016, 10:15 PM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
We don't do any tensioning on our first stage belts, it is what you have described. I don't think there are huge backlash savings based on having a belt vs gear drive on that stage, because the...
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Forum: Robot Showcase
06-10-2016, 01:24 AM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
I can't quite speak for our vision team on all of the implementation, but I can fill in some high level details.
We do have two cameras. There was an early thought to use them to do stereo (do...
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Forum: Robot Showcase
06-10-2016, 01:16 AM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
We didn't really have a secret, other than the double wheeled shooter seemed to be not very sensitive to them (consistent to what we noticed in prototyping). We also had a pretty flat shot (helped...
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Forum: Robot Showcase
06-01-2016, 09:16 PM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
We shoot for what I think is described as a transitional fit (+- a couple tenths off of nominal). We used to just sneak up on it and test fit it, but this year we got access to an optical comparator...
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Forum: Robot Showcase
05-14-2016, 10:14 PM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
The 5mm GT2 belts and #25 chain have comparable load ratings. To use a belt in the same application would require a huge sprocket, which would be heavy, wide, and require a lot of custom work. Much...
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Forum: Robot Showcase
05-14-2016, 09:43 PM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
That gearbox is our hanger winch. One end of the string went there, the other was tied on the other side. That way we didn't have to have a winch gearbox/line centered on the robot and got a 2:1...
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Forum: Robot Showcase
05-14-2016, 05:54 PM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
We had a mixup when putting the file on the server and got the wrong extension on it. The file was saved as step, you should be able to open it fine if you rename the extension to .step. We are...
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Forum: Robot Showcase
05-14-2016, 02:03 PM
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Replies: 125
Views: 38,270
Re: FRC971 Spartan Robotics 2016 Release Video
Our CAD is now available at http://frc971.org/cad
It takes the server a little over 10 seconds to start the download once you click the link so please be patient and don't hit the link twice.
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Forum: Technical Discussion
02-25-2016, 01:54 AM
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Replies: 22
Views: 2,602
Re: Diagnosing Belt Skip Under Load
If I got it correctly from the video, you have a 63 to 1 reduction with a 2:1 reduction after that. The bags are about 1/5 the torque of a CIM, so 1/10th the torque of a 2 CIM drive. I am going to...
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Forum: Programming
02-19-2016, 03:25 PM
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Replies: 12
Views: 1,614
Re: Dual encoders
We have encoders and potentiometers on all of our joints, both for zeroing and fault detection. Last year we correctly e-stopped our elevators when one of the encoders got unplugged. Not the...
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Forum: Technical Discussion
01-24-2016, 07:04 PM
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Replies: 28
Views: 3,841
Re: 775 Pro Coupling
We buy and broach pulleys from SDP-SI. It is a lot easier only having to source pulleys and not pinions. We previously had issues reliably sourcing pinions. It would be nice to be able to buy hex...
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Forum: Inventor
12-04-2015, 12:20 AM
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Replies: 24
Views: 2,385
Re: HSM Express+Tormach undersized holes
I would recommend leaving it disabled. I will sometimes use it to compensate for bore size. For instance, if the model is 1.125 and we want a 1.124 hole without changing the model, we will put...
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Forum: Inventor
12-03-2015, 11:33 PM
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Replies: 24
Views: 2,385
Re: HSM Express+Tormach undersized holes
.020 is the default stock to leave for HSMExpress, and I have found that this often gets put on for default for pockets (and pretty much always for adaptive clearing). What machining technique are...
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Forum: Technical Discussion
11-08-2015, 01:08 PM
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Replies: 24
Views: 4,905
Re: 110ft/s (75mph) robot design
I couldn't find a statement in your reference to wikipedia that the efficiency is <85% for the NuVinci transmission, but found 85% used in a hypothetical analysis in a discussion of the tradeoffs...
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Forum: Extra Discussion
10-24-2015, 03:51 PM
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Replies: 24
Views: 4,413
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Forum: Technical Discussion
10-18-2015, 08:35 PM
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Replies: 37
Views: 4,279
Re: Dog Shifting Gearbox Feedback
We have run unlightened 090 5052-H32 gearbox plates without any bends for a couple of years. The only issue we have had is that the VEX hex bearings (or at least the old ones) don't press well in...
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Forum: Technical Discussion
10-01-2015, 12:04 PM
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Replies: 16
Views: 3,392
Re: Belt Driven Drive Trains
Gates actually recommends that you down rate the maximum torque of a belt system when the center to center distance is short, however this is assuming a properly tensioned system. They have more...
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Forum: General Forum
09-24-2015, 09:17 PM
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Replies: 20
Views: 4,661
Re: 971 CNC Router
We are using a 3HP, ADES70, 24,000 RPM Electric Spindle from here (http://www.pdsspindles.com/manual-tool-change/ade-standard-series).
We are running AMC motor controllers and brushed motors with...
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Forum: General Forum
09-23-2015, 05:20 PM
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Replies: 20
Views: 4,661
Re: 971 CNC Router
Releasing something is definitely an option, I would have to look through the state of our documentation. Probably won't happen until after the season, as we have a lot of projects that we are...
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Forum: General Forum
09-22-2015, 10:38 PM
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Replies: 20
Views: 4,661
Re: 971 CNC Router
Having a machine with more rigidity and low backlash lets you make more precise cuts and aggressive cuts, so we can make better parts faster. Our preliminary testing shows that the machine is...
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Forum: General Forum
09-22-2015, 11:51 AM
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Replies: 20
Views: 4,661
Re: 971 CNC Router
The router does a good job of complimenting our manufacturing sponsors skill sets. We still plan to have similar levels of sponsor involvement during the season, but we will be able to prototype...
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Forum: General Forum
09-22-2015, 01:30 AM
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Replies: 20
Views: 4,661
Re: 971 CNC Router
We decided to build a router after the 2014 competition season, and got it cutting parts this past August. We made the 3rd robot (the one we used at Chezy Champs) almost entirely on the router, and...
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"Oblivious" people asking questions are what gives us an excuse to sit around on CD. - Ryan M. [more] 
