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-   -   pic: 4183 Testbead Chassis (http://www.chiefdelphi.com/forums/showthread.php?t=110064)

z_beeblebrox 18-12-2012 17:05

Re: pic: 4183 Testbead Chassis
 
Quote:

Originally Posted by MrForbes (Post 1202878)
It looks like a plastic wire duct. A cover snaps over it. Keeps the wires organized and protected. But that's just a slightly educated guess.....

It's a very good guess. The duct should help keep the robot's wiring much neater.

CalTran 18-12-2012 17:08

Re: pic: 4183 Testbead Chassis
 
Quote:

Originally Posted by z_beeblebrox (Post 1202948)
It's a very good guess. The duct should help keep the robot's wiring much neater.

Looks like the wires go the wrong way, maybe?

Conor Ryan 18-12-2012 18:04

Re: pic: 4183 Testbead Chassis
 
Great job for some rookies!

I work on the fields at competition, I see a lot of really weird things done with electronics. If you want to make them last, and fairly maintenance free, don't mount them face up like you did in this picture. Mount them standing or face down (just rotate the crio 90 degrees). It keeps all those pesky metal/wood shavings and dust from causing lots of issues down the line.

It certainly doesn't look as nice quickly, but if you take the time you can figure out a way to make it look real good. (And don't forget your Radio too!)

This step is crucial if you use jaguars also, but the victors and talons can probably get away without.

kuraikou 19-12-2012 19:43

Re: pic: 4183 Testbead Chassis
 
Quote:

Originally Posted by alb4h (Post 1202860)
What is the metal 't-shaped' piece mounted between the power distribution board and the CRio?

Yes it is a place to put the wires so that they are all nice and neat. As previously mentioned this will probably have a bunch of prototypes attached to it so it needs to save space and be able to be easily movable/removable and if the wires are tangled that will be difficult.

nixiebunny 20-12-2012 00:00

Re: pic: 4183 Testbead Chassis
 

Here she is, all wired up and power applied. Still need to write some code... the programming team is learning Java robot programming this year, so they now have a nice, big, dangerous toy to work with.

MrForbes 20-12-2012 08:27

Re: pic: 4183 Testbead Chassis
 
looks good bro! With a few cross braces, that would be a stout chassis.

Nathan Streeter 21-12-2012 09:27

Re: pic: 4183 Testbead Chassis
 
Looks very clean - great job doing some educational, practical off-season work... best earmark of an improving team, in my opinion!

I second those who have mentioned teams using wood drivebases... it can be done very well and can be significantly easier to fabricate. I recall 173 - at least on their 2007 robot - used a many-ply (9 or 11?) birch plywood of about 3/8".

I don't have any experience with wood drivebases personally; however, our team (especially in it's early days) tended make things way too beefy and heavy. I know Oak is surprisingly dense, so I recommend intelligently experimenting some with using thinner/smaller parts in lower-load areas (it's easy to use a heavier member than needed just because you use it elsewhere... we've done this with 80-20, when many components could be 1x1x1/16 box alum, which is half as heavy). Speed-holing can also provide some weight savings... although I have also seen teams over-speed-hole a critical points. All that to say, "Be careful of surprisingly heavy drivebases... a 6WD doesn't need to weigh >50 pounds without electronics."

Also, if you're looking to save weight, switching to #25 chains or timing belts can be a good way to do it. The larger your sprockets are compared to your wheel diameter, the less tension they're subject to... A small change I recommend with little/no cost is to make the longer chain runs between the center wheels and the end wheels #25 chain instead. With a >3.5" sprocket, I would be surprised to see a failure on that chain run, but even then you'd still have 4 or 5 driven wheels.

It looks like you're using a 3/8" bolt for your axle... which I like using for dead axles... although be careful not to over-tighten them! I would recommend you make sure it's a Grade 8 bolt, though. From our team's experience, a standard (Grade 5) bolt is unlikely to hold up in competition.

I would strongly recommend implementing now the stiffness modifications you expect to make... Drive Bases - particularly 4, 6, and 8WD ones - take a surprising amount of internal load. A particularly important degree of stiffness is bending along the diagonals (when viewed from above). Drive Bases with insufficient stiffness can make a 6WD base with plenty of "center drop" hop. It's important to have a sufficiently strong drive base if you're going to be testing and comparing different drive trains, so you can get useful experience with each.

Best of luck this year!

JamesCH95 21-12-2012 10:01

Re: pic: 4183 Testbead Chassis
 
OP, great looking chassis! That's an awesome off-season project.

95 used wooden chassis almost exclusively until 2005, then a few more times since. Mostly in the pre-bumper days. It's a great what to make a chassis. We typically used 9-layer birch plywood connected with 1"x1"x1/8" aluminum angle and bolts if memory serves.

Bill_B 21-12-2012 10:09

Re: pic: 4183 Testbead Chassis
 
All good advice from the responders here. Useful ideas for the construction of your competition machine. I'm sure the team is mindful of the rule concerning modifications of COTS parts prior to kick-off. I'll be showing your pictures to my team so they can see what they should have done with their last two months. :yikes:

nixiebunny 23-12-2012 00:00

Re: pic: 4183 Testbead Chassis
 
We got the bot driving yesterday using Java at our new build facility - a high school that we'll be doing a co-build with. As the manipulator subteam mentor, I'm looking forward to testing the new game ideas with it. The wooden bot's name is Stormageddon, as I as informed yesterday.


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