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Mini Sumo

#1

Ok, I think I have an important project that I want to do. I saw competitions that are being held at two universities close to my residence, and the CNRG. It would be fun to build a mini sumo to be able to go to competitions. So I saw these motors : robotshop.ca/home/products/r … motor.html

Are those the motors you guys are using for your mini-sumos? Anyway, they look small powerful and fast… If you have recommendations for motors, go ahead, please :slight_smile:

I’ll take a trip to home depot try to find lexan( or derlin, wich one’s should I choose?) and some aluminiun bars. I’ll order 3 IR rangefinders (one in the front and one on each side) and a motor controller (suggestions? custom made?)

And I will probably use the mini ABB and Atom to control the robot since that’s waht I have on hand. I don’t want to spend to much. I saw a cheap motor driver from solarobotics (20$) That can take enough current for the motors I linked. I will also order 1-2 (I would maybe put one on the front left and the other on the front right side?) detector to see the white of the arena.

I think that’s the basics of the project. :arrow_right:

Once I decided on wich motors, I will buy the whole lot not to pay 2 times shipping.

#2

Sam,

I use them and I like them.

brooksbots.com/ExSpurt.htm

There are several other mini sumo robots being built with them.

I think that the supply is very limited, so buy them fast.

   Rick
#3

Ok, That’s good! Other guys who are using it?

Now: my second biggest problem is the motor controller, here’s one I saw not too expensive: robotshop.ca/home/products/r … r-kit.html

Do you guys know how I could connect it to the mini ABB? And I wonder how I could program it? Or should I invest more money to buy the sabertooth 2X5?

#4

I’m using those motors in my new mini sumo Seeker 2x:

huv.com/miniSumo/seeker2x

Lee (Spacejunk) is building a new mini-sumo with them.
Jerome (robomaniac) (another guy from somewhere around Montreal) is building one as well with them.

I’m using two of these boards for motor control:

pololu.com/products/pololu/0711/

I could never fit the Solarbotics h-bridge inside Seeker 2x, so I needed something that was much more low profile. The other really nice thing with the Pololu board is it gives analog feedback for motor current consumption.

I don’t know anything about the mini ABB, so I can’t comment on that…

  • Jon
#5

But, like the motors, they say it goes at 16500 RPM… That’s REALY too fast… No?

#6

An ABB will not fit in the space you are allowed, google mini sumo robot rules to find the dimensions you need.

Those motors are probably a little hard for a novice to tame. I would start with a simple kit like this. It is sumo battle proven and many winning robots were built with the solarbotics kit. It is usually much cheaper than a scratch built.

#7

Yeah, I know the rules, it would fit… but very very tight.
I think I will go with the motors above and I guest I will design my own board. it’s pretty tight space… What should I use like controller?
Anyway afterward I want to reuse the parts

Those motors are 6V, do you actualy use that? it’s 150 grams(the batteries)! Do you like underpower it?

#8

Sam,

Yup, way too fast. I’d rather have 25:1 or 30:1 gear box.

Exspurt has been running at half speed…amost 50 inches per second. I have been slowly upping the speed as I get more traction. Now, Exspurt is over 60 inches per second. I don’t think that it will ever run full speed under control (100 inches per second).

      Rick
#9

So you give about 3 volts instead of 6 so it will go less fast?

#10

I would just go with the solarbotics kit to start, than you can get a feel of the event and build something. Did you even look at that link?

#11

Yeah I did… it looks real interesting… I’m not sure :laughing: It looks fun, it’s true to start it would be a nice place.

#12

Rick,

I don’t understand where these numbers come from. As far as I know, Exspurt has wheels that are about 1" in diameter, or even a little less.

At 16500 rpm, you’re looking at 970 RPM at the output shaft, which is 16 RPS. With a 1" diameter tire, you’ve got a circumference of 3.14", which works out to about 51" per second.

In order to get 100" per second, you would need 2" diameter wheels…

  • Jon
#13

Jon,

16,500 rpm is at 6 volts. I use three Lipos.

I measure speed, not rpm. When I did the speed runs, the batteries were 12.15 volts (no load). The wheels are 1 inch dia.

At 50% power ExSpurt travels 47 inches. According to the Lynxmotion speed calculator, that is 900 rpm.

At 79% power ExSpurt travels 78 inches. Again, that is 1490 rpm shaft speed.

Any more power than that and the tires spin on acceleration and lock up under braking. Those are the results of the first speed tests that I did over a year ago.

      Rick
#14

I believe the motor is supposed to run at 6 volts and not at 12 volts…

16500 RPM’s with a 17:1 ratio, tht would do about 970 RPM, so about 50 inches a second with 1 inch wheels?

So what do you guys, should I do like spacejunk recommends or should I go with building my own (it’s not at all the first robot I’ve done) ?

#15

It really depends on what makes you happy. Building an advanced mini-sumo using the Maxon motors is difficult and expensive, and they are crazy hard to control.

You might be better off building a more standard mini-sumo first, with more reasonable (slower) motors to get a feel for how it all works. But its really up to you, and what you’re comfortable with.

  • Jon
#16

Well, if I get my ABB to connect to my computer, I will probably go with a custom made sumo because it will make me happy for a longer time :laughing: It’ll take a while to make/program and all.

#17

Hi!

Do one of you guys have a site (or book) you know that you could refere to for building circuits with Atmel chips, because I’m at a lost to where to start… I only did some simple electrical circuits with some IC’s, but I don’t know how to do this…

Help please :laughing:

#18

um, first suggestion is narrow the scope a bit by listing what it is you need to do. how many inputs, outputs, what types of inputs and outputs, yada yada yada. this will help you drill down to what the minimum number of things you need in your micro are, eliminating the bottom of the list. Then you can consider what there is left and figure out if any of the extra features you may gain by going up the list will really gain you something or just be overhead.

#19

societyofrobots.com/

They have some great tutorials…

  • Jon
#20

Ok, I’m presently reading the thingy…

For note : maybe
-3 edge sensors
-3 IR range finders
-motors (dunno amount)

I think that would do. Now, how can I calculate the torque I need to push my robot + the other robot?