I am new in FOC, I was trying to find the answer all over the forum, unfortunately, found just 1 thread that mentioned the topic I am interested in.
Is it possible to use a potentiometer to control the speed of the motor?
We do support a very similar sensor which is magnetic sensor with an analog output. It outputs the voltage that is proportional to its position, so exactly the same as the potentiometer.
Now it all depends on your motor, your mcu and your potentiometer. Keep in mind that the position sensor needs to be precise and very sturdily fixed to the motor.
Can you tell us a bit more about your setup?
I am planning to use bldc motor with Arduino and L298N (more likely, I will switch to MOSFETs later, as L298N kinda old grandpa and have an issue with overheating).
The purpose of the use is rotation on different speed but with constant torque, as from the beginning there will be no torque at all and with time it will gradually increase (in a reasonable way, not like, trying to lift an elephant), I spent quite a lot of time surfing the web and found that FOC is ideal for this application as it can hold the torque quite stable.
Is it possible to use hall sensors as a magnetic sensor?
The problem with mechanical potentiometers is that they will be very noisy as the centre-tap scapes across the resistance, and the lifetime will be limited. I’m not sure they’re really designed as precision sensors, nor for continuous movement…
I assume there are better potentiometers used in high end audio equipment or something, but this doesn’t sound cheap (or small).
I think the magnetic sensors were invented at least partially for this reason - to be contactless, and precise.
Internally, the magnetic sensors use hall elements, so yes, you could make your own magnetic sensor using hall elements, but I think it would be difficult. The sensors contain many hall elements arranged in a pattern, and use sophisticated filtering to get good results.
If you’re trying to do this more cheaply, or roll your own for other reasons, I think classic encoder disks and an optical sensor in quadrature mode will be easier to implement and get you accurate results.