Mechanics and Construction > Mechanics and Construction

new to motors... please suggest the ratings..

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extreme.aly:
I'm making a robot for a competition in which the robot have go thru a maze and pot three different coloured balls (balls already placed on the robot) in the respective coloured boxes..

i think two motors (for driving purpose) will do the job.. one for left, and other for right.. i'll be using two 12v batteries, one to power up the ics (obviously after stepping it down to 5v) and the other for the two motors..

one more thing.. i'm thinking of having a 4-wheeled robot.. 2 on each side.. and use a chain to drive both wheels with a single motor..

if we suppose that my robot weighs 5-6kg, what motors i should use? i need torque and a little speed too.. i need it to be quick to start and i also need it to stop instantly (obviously when signals are received from microcontroller).. please help!

thank you :)

newInRobotics:
We need wheel radius to give You torque estimate :)

jwatte:
How big is the maze? It sounds to me as if you could solve this with way less than 6 kg even for a pretty big maze (say, two-foot distance between walls.)

I think any of the Pololu 25D or 37D gear motors would work fine. Typically with mid-to-lower gear ratios to get some speed -- between 1:20 and 1:50.

Also, you'll want to look into getting motors (or wheels) with encoders, to make sure you can tell when you're driving straight!

If you have one motor per side driving, you don't need a chain to drive both wheels. That just adds complexity. Unless the maze has hazards like oil slicks or ice patches or whatever...

extreme.aly:

--- Quote from: newInRobotics on February 14, 2013, 07:52:45 AM ---We need wheel radius to give You torque estimate :)

--- End quote ---
its around 3.5 - 4 cm...

--- Quote from: jwatte on February 14, 2013, 02:13:40 PM ---How big is the maze? It sounds to me as if you could solve this with way less than 6 kg even for a pretty big maze (say, two-foot distance between walls.)

I think any of the Pololu 25D or 37D gear motors would work fine. Typically with mid-to-lower gear ratios to get some speed -- between 1:20 and 1:50.

Also, you'll want to look into getting motors (or wheels) with encoders, to make sure you can tell when you're driving straight!

If you have one motor per side driving, you don't need a chain to drive both wheels. That just adds complexity. Unless the maze has hazards like oil slicks or ice patches or whatever...

--- End quote ---
the distance between walls is 50cm..well i really dont know how much its gonna weigh with all the motors and the body..
if not chain, how do u suggest i drive both wheels with a single motor..?

jwatte:

--- Quote ---if not chain, how do u suggest i drive both wheels with a single motor..?
--- End quote ---

You said you'd use two motors. I suggest driving the left rear wheel with one motor, and the right rear wheel with the other motor, and leaving the front wheels un-driven. If you can add servo-based steering, you'll be better at turning, but you can probably do without it.

Or just put in four motors. Motors are cheaper than transmissions and linkages these days... Look at, for example, the Wild Thumper series for design ideas.