Big Minibots

Since teams have been posting pics and vids of their robots and minibots something I have been noticing as been getting to me. Why is it that alot of teams are building these huge and complex minibots? I mean teams are building minibots that look like they are maxing out the size limits near 12"x12"x12". Why build a big one over a small one? Pros? Cons?

IDK - Because they can?

Why bother to even start this conversation?

It’s pretty apparent from your remarks that you already understand that others’ design processes greatly differ from your team’s design process.

Such negative posts. The reason I started the thread was to see if anyone with a huge minibot would post as to why they made theirs so big compared to a really small one

Jack and Jesse,

There are many advantages to having this kind of thread.

The original poster was asking why the decision was made for the large minibot. Do they feel that the additional weight is counteracted by something? If so what is it?

Please don’t post in a thred to belittle the person asking a legitimate question.

In fairness to Jack and Jesse, the original post was worded in a way that seemed to insinuate that a larger minibot is a terrible idea that no team should have used. As a mentor of a team that has built a larger minibot, I will say that it mostly came down to us finding a design that worked for us. Could our design be more compact? Probably, but after several design iterations that failed miserably, we are happy to have a functioning minibot regardless of its size.

A 4 inch minibot has more distance to travel to the top than a 12 inch minbot. Ours is at the max of 12 inches and can travel up much faster than some a fraction of its size and that is before lightening and speed holing!

But we are definitely not faster than 118,148,217,and 1114! :wink:

That all depends on how close to the deployment line you deploy either of them.

That is true, but again it depends on where they deploy from and I have seen several deploying near the bottom.

We didn’t figure out how to make a small minibot.

I expect many other teams have the same reason.

Just put it in the dryer for a few extra cycles. That should shrink it down nice and small.

Our team just sort of figured that it would be easier to try to push 5/6 pounds up the pole, instead of 12-15 pounds. We want to maximize the traction, using 2 wheels, and minimize the drag. We aren’t using magnets to hold ourselves, close to the pole, because of drag. We using 2 semicircular pieces of PVC, that are connected, like a hinge and open, before deployment, and snap together, after deployment. The magnets will hold the open ends together.

I think that this trend partly results from using the Tetrix structural components in one’s minibot. When my team was prototyping designs using Tetrix parts, we found that we had to have significant structural members to get things like motors, gears, and wheels in proper stable alignment. When we later built a custom minibot body, we were able to mount all the components exactly where they needed to be, saving weight and volume.

Then again, we ARE using a minibot that has a single motor and wheel…

our 15 lb minibot gives our hostbot the extra traction it needs to push around other robots with ease. :slight_smile:

edit - We didn’t actually do this, but I wanted to… I am sure some teams did it.

The most obvious thing I can think of is that a taller minibot can be deployed closer to the ground and hit the target as soon as a shorter minibot. Depends on the design.

Potential reasons:

  1. Because they don’t have someone who understands Physics leading the design.
  2. Because they don’t read Chief Delphi
  3. Because they are ignorant of the world around them.
  4. Because they lack the resources, or design experience to build something custom

I don’t mean this post to be harsh. I lot of teams have put a lot of work into some very successful larger minibots. But as a matter of engineering and physics principals, a small and light one is the only correct way to do it, if the goal is to get to the top the fastest.

As a famous engineer likes to say, design is an iterative process. I’ve visited the pits of a few teams* that began by building larger, heavier minibots, and evolved their designs toward smaller, lighter minibots. The physics is the same, but the numbers (weight, friction, wheel diameter, gear ratio) are different. Lighter = faster, after you get the design optimized.

*One of those teams has a leader who is also a physicist, and a teacher. I am certain she did not do the design for them, but I am also certain she did not allow them to believe their first design was good enough. The advantage of understanding the physics behind an engineering problem lies in knowing how to predict the theoretical best-case result – after you have that knowledge, iterate until your actual result is so close that further effort is better spent on something else.

Consider two teams on a dysfunctional alliance: both race to the same pole at the same time from opposite directions…

One has a 15 lb maxi-minibot…
the other one has a 2 lb mini-minibot…

oooh, the horrible noise…, then…

the maxi-minibot slowly climbs the pole with what’s left of the mini-minibot wrapped around the maxi-minibot’s chrome hood ornament. :wink:

Aaahh, but it’s the twisted wreckage of mini-minibot that flattens into the tower plate with no worries about not providing enough force for long enough.

But no points are awarded because the mini-minibot did not use power from its battery and motors to climb the pole.


Can a 15 pounder with a “cow catcher” intentionally scrap off little minibots that get stuck on the pole?

That might be fun to watch.


We design for being on a dysfunctional alliance: all the time.

I think it just ends up what works for you and your materials. If you can only use the Textrix parts and you don’t have access to custom parts, you probably will have a bigger and heavier minibot. Its not that you are ignorant or anything its just what works for you and what you have. If you have unlimited resources you probably will have a small light minibot.

If one of the resources is “engineering talent”, then yeah, having more resources helps. But you don’t need much as far as tools/equipment/money to build a nice one. 330s minibot is amazing.