Hi!
I just wonder the PWM signal changes the current tor voltage?
In the Components description, the motor work in 6V DC, and the stall current is 2.2 A.
Does it mean the PWM signal controls the current?
Thank you!
Hi Chokings,
Just to be sure, the stall current is the current that an electrical motor draws when its shaft if prevented from moving. This is typically the highest current a motor will draw.
Using PWM signal we can control the electrical power by changing the proportion of ‘on’ time to the regular interval (that is to say, by changing duty cycle). By ‘on’ state, I mean the state when voltage is 6V and by ‘off’ state, I mean the state when voltage is 0V.
By Ohm’s law and electromagnetic theory, the current value is related to the voltage, resistance and shaft load. In simple terms, this is the reason why the current value is unstable.
Motors in ROSbot are controlled by CORE2. There are few h-bridges on board. Using two signals from MCU we are able to set 0V or +/-6V output. Proportion of ‘on’ to ‘off’ time determines the average voltage provided to the motor, which means that we control the voltage. And the current value is determined by both average voltage and the mechanical load.
Best regards,
Paweł
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Hi Chokings,
I have just specified the last paragraph of the above post so you can check it out. You can also look for materials about it on the Internet, because the PWM control in our robot is a classic example of controlling any DC motor with H-bridge and PWM.
Best regards,
Paweł
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