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Topic: What should I consider when I choose motors for my robot (Read 659 times) previous topic - next topic


Hobbyist here.

I designed a robot, but it has never moved. The motors are weak, what are the things that I should consider when I buy new ones. I am building small and medium robots.

I don't wanna use built-in chassis, it limits my design options.

- I am building a robot similar to this one, I am using Iron to build the chassis. This guy is using Iron-chassis, and his robot is so damn fast (+ the video is old). Would you recommend some motor-types, or a place where i can learn how to choose motors and buy them.

- My second question (to not make duplicated question), If I need to build medium-size robot like this one, would you please explain the type of motors/batteries that I should consider.

Any point, help, or hint is appreciated


The first link it looks like some spur geared motors are being used. The two most important things to consider are RPM and stall torque. You can't change those two characteristics of a motor directly, but you can always use gear ratios to try and get the right output.

Also, consider the power requirements. That is easily calculated by using about half the stall current rating as a good indicator. Ideally, you just hookup a meter and run your bot at full use and actually measure the real power use.

Brushed motors are used for applications that require some torque to be applied even when there is no power available or when scaling of speed and torque is somewhat important. Brushless motors are used for high rpm and low torque applications or when you don't want to worry about breaking a gearbox if the motor were to suddenly be stopped because it hit something.

Servos and stepper motors are used for positioning things precisely.

Generally, the higher the stall current is, the more powerful the motor is likely to be. Consider the RPM though as well, since a 5 RPM motor with a 50A stall current could definitely move your robot, but it would be painfully slow even with a huge gear ratio.

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