How do I make a solid robot?

Not sure what to title this post, so the title might not match 100% with content.

I was recently watching 354X deploying their tray and noticed that it looked clean and even sounded really nice, everything about it was just very smooth. This also is shown with lifts (either arms in TT, or Delta IV Iteration 3 's wonderful DR4B) not having any vertical bounce, almost if they are locked in place whenever they move up/down .

How can I build a robot that also does this? I’m mostly looking for info on lifts and how to remove bounce in lifts, but any info would be appreciated

make sure to brace well and keep everything sturdy so there is the lift itself isn’t loose .


Zipties and ductape brother


For lifts specifically use the least amount of gears possible. Also part of why Delta IV’s lift looked so smooth is because it probably ran on PID loops. With buttons controls a lift would be forced to do hard stops which would exaggerate any bounce that a lift has, but with a control loop it would be much less noticeable.


. Make sure to use plenty of bracing, but not too much to make it heavy.
. Use bearing flats on every joint. Box the c-channels that twist alot on arms.
. If they aren’t on arms and they bend inwards, use a screw that goes through both sides of the c-channel with spacers sandwiched between. This stops the two sides from bending inwards if you have the right amount of bearings.
. Use locktite on all standoffs because they come loose way too easily.

Those are the basics

Edit: use screw joints whenever possible (everything that isnt too long and isnt driven by a motor) 333a dr4b tutorial can help


I didnt even think about the programming side of this, PID loops would have proably been the solution to my tower takeover bot arms. We only used PID to slow down the stacking but had button control for the arms. Thanks for the help

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In terms of bracing, what matters more is where you put your bracing and now how much. You could have large boxed 5 wide braces that only go in the center of the base but it will fail structurally compared to a base with spread out braces on both the top and bottom.

In terms of overall building, using some form of a 90-degree bracket to align base C-channels is a very useful tool when trying to make brackets align for proper spacing and reduced friction in axles. Using shoulder screws wherever possible is also very helpful to make sure channels aren’t misaligned when bolting them in. A neat alternative to this if you don’t have any is to align the channels into the corners of the holes and then bolting down as hard as possible, This somewhat has the same outcome as shoulder screws in that it will be a confirmed alignment, but spacing on the inside might be somewhat different if you do so.

Other useful building techniques would be boxing through any main bracing channels with spacers or understanding what braces to use in what applications like lift gearboxes or the main bar supports on a DR4B.


Use screw joints on everything. A screw joint can resist twisting sideways really well, making your lift very solid


I need to buy shoulder screws still, hopefully I will have some when I start building

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If you build a dr4b, make sure not to make the actual lift out of steel… Our sister team did that last year and although it was ok, it definitely broke on them due to sheer weight.

oh that sounds bad, I try my hardest to never use steel. My TT bot had on 1 peice of steel on it where the tray was connected to the drive base

If they would have just made it out of aluminum it would’ve been a pretty good lift, but yeah definitely use aluminum on lifts, especially if it’s going to be holding a bunch of game elements.

I have built many dr4b’s and there are two things that I have found that can help reduce the bounce:

  • Make sure that your gears are solid and fit good together, if you have a axle flexing in the gears you will see it in ends of the lift. Check all screws and connections
  • Rubber bands need to be done correctly and you need to have the right number of rubber bands on each side. You want to be able to let go of the lift (without motor power) and it will stay where it is
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Also, side note, we found that using less rubber bands on the top of the lift made it work better…


Fine tune the amount of rubber bands needed.

Then If you’re too lazy to use pid, then just use motor hold.

I would recommend against this. PID gives a smooth stop while motor hold stops the motor abruptly which leads to sudden a shift in inertia which I have seen too robots. If not PID, coast the motor then hold it.

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Fun fact, the motor hold works off of PID. It’s not good for accurate auton tho.


Yeah I think the problem was more of the abrupt stop of the arm than anything else