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Unread 15-10-2014, 22:05
Andrew Lawrence
 
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Re: pic: FRC3880 - Tiki Techs - 2015 Prototype Drive

Quote:
Originally Posted by TikiTech View Post
Poorly thought out is not very helpful..

What do you think is poorly thought out?

Current weight without the battery is 25lbs including electronics shown.

This is our first attempt at a hex frame. Most of this design was based on what materials we have or can get locally. Being in Hawaii, shipping stock material to prototype with is very expensive, so we have to be creative with what is on hand and available. There is nothing here but Lowes and Home Depot. No real machine shops or metal vendors or the like here.

Being a 4th year team we always enjoy learning different ideas, constructively..

Mahalo!
I use the term "poorly thought out" very loosely. It's just part of the vocabulary. What I mean to say is I can't tell your train of thought in this design, and there are many design choices I question because I do not understand the reasoning behind them (hence why I asked about your thought process behind it).

What I see when looking at this frame immediately is the large quantity of gearboxes, and the large quantity of CIM motors. I understand earlier you said you made the decision of the 8 motors for the sake of "more power", but doing the math on my end shows marginal improvements in usefulness that do not seem worth the extra weight nor the risk of blowing the breaker. So I'm wondering what was the in-depth reasoning behind your choices for 8 motors, as well as the initial reasoning for 4 different gearboxes (I know you said you're planning on a new gearbox, but I'm curious about why you thought 4 different ones was the best solution initially).

Also, your frame layout with the 2x1 making the hex on the sides makes me question if you will be able to take your wheels off. For a true WCD the ability to easily remove your wheels is invaluable at times, and it appears like you're sacrificing this ability to shape your frame in this method. Out of all the ways to make a hex shape, why did you choose this one?

Speaking of framing, your 2x1 appears to be 1/8" thick - the more common style for a WCD - so with all of your tubing non-lightened, 8 motors, 4 gearboxes, and colson wheels, I really have a hard time believing that this drive system even without the electronics is 25 lbs. You have almost 20 lbs solely in drive motors, let alone solid 2x1x1/8 aluminum tubing and 4 large gearboxes, and then the added electronics makes it impossible for me to believe this is 25 lbs.

Your constructive iteration is the key to success - I just try to restrain from constructive criticism until I understand the thought process behind the design, so that I can better focus my advice towards the design and the designers.
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