Mechanics and Construction > Mechanics and Construction

Motor strength (chosing motors)

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mgolu24:
Please help me whit motors. I dont know what motor to pick for driving my robot. i want to make a fighting bot so moving around 10-20kg. please help.(btw the robot will slam others, it wont use any weapons so it hast to move fast)

thanks

This tutorial tells you how to calculate it:
http://www.societyofrobots.com/mechanics_dynamics.shtml

If you have trouble, just tell us what is confusing and we will explain.

For ramming style battlebots you want the highest momentum possible, so choose a high velocity and acceleration.

mgolu24:
i dont understend many things on the page. maybe it would be so hard if i would know more english. i know english but i dont understeand velocity, torque and things like that.the bot will (must) be under 1000mm x 1000mm x 1000mm (1m x 1m x 1m) dimenzions. i intend to figth bots like these http://borberobota.com/roboti/roboti.htm , so i want a motor that moves my robot so that i can crash into the other robot whit my spikes :), oh and it would need maybe a litle bigger wheels because i intend to have the wheels on the both side, cause if the bot flips so i can continue fighting

haha ok, that explains the strange typos . . .

Velocity is how fast the robot moves. If you are driving a car at 30km/hr, that is velocity.

Acceleration is how fast the robot can increase velocity.

I recommend using about 1.5m/s acceleration, with velocity at 2m/s. Lets say mass was 20kg.

Now use this equation:
Torque * rps > = Mass * Acceleration * Velocity / (2 * pi)
this becomes
Torque * rps > = 20kg * 1.5m/s * 2 m/s / (2 * pi)

Now find a motor you like to buy, and multiply the torque and rps of that motor together. If that number is higher than the calculation on the right side of the equation, then that motor will do what you need.

If you cant find a motor that will work, you will have to reduce expected mass/velocity/acceleration.

mgolu24: