The robot is as far as I know set of the microcontroller, Motor controller, sensors and actuators with other mechanical accessories.
And the potentiometer (for controll speed of servo) and Analog to digital converter (and vice versa), whether it connects specifically to the microcontroller board with wires like everything else or is built into the microcontroller board as component of those board ?
It would be great if you could tell us what microcontroller you are planning on getting because they are all different. Some boards include ADC’s and some don’t, for example, on the Arduino there is a 10-bit ADC meaning it has the ability to detect 1,024 (2^10) discrete analog levels. Some microcontrollers have 8-bit ADCs and some have 16-bit ADCs. On the other hand a Raspberry Pi does not include a hardware analog to digital converter, but an external ADC (such as the ADS1115 can be used. You can read more about this here and here.