# Choosing right motors for self-balancing robot [closed]

I’m looking for right motors for my first self-balancing robot.

Design assumptions:

• robot height: around 120-200 mm
• robot weight: around 600-800 grams
• wheels: 80x10 mm or 90x10 mm
• battery voltage: not sure yet, but something between 7,2 - 12 V (depending on the motors)

So as I know, I should looking for DC motors with encoders, right? I also thought about stepper motors.

My little calculations:

Required torque = robot height * robot weight * gravity * maximum tilt angle

$$Rt_{min} = 0,12 m * 0,6 kg * 9,81 \frac{m}{s^2} * sin(40^\circ) = 0,454 Nm$$ $$Rt_{max} = 0,20 m * 0,8 kg * 9,81 \frac{m}{s^2} * sin(40^\circ) = 1 Nm$$

So, in best scenario I will need 0,454 Nm and in worst 1 Nm. So, if I have two motors then I can divide this required torque by 2, right?

Can you advise me on the right motors for my project? I’m not sure about motor speed, gear ratio and how much torque do I need to get good balancing without damaging/overloading motors.