Ok, here is the thing that I know. When you buy a motor there are two different things you should put in mind, torque and speed. All motors have an internal torque, let’s call it the main torque. Motors speed usually measured in Round Per Second RPM, notice that all manufactures consider this as a “no load” speed. In physics, torque is considered as the angular force that is perpendicular to the distance. <What I said so far is just a review so everything after this makes some sense>
Why using gears? You use gears to transfer “the main torque” and to reduce the speed of the motor and transform this to an “additional torque” added to the main torque.
So the total torque according to this is total torque=additional torque + the main torque.
According to physics also, the number of gears is determined how much torque you want to transfer and get from the speed.
What does PWM do? Well, it controls the speed, but without gears the additional torque will not get formed. That’s why I was surprised from this.
Electro, your idea is to use a feedback circuit that tells the PWM source, the microcontroller, to pump up more pulses, Considering you are using an encoder for the brushed motors or hall effect sensor for the brushless motors, is a bad idea for one single reason. You are using only the main torque. That’s will be a disaster if you have a small motor without sufficient “main torque” to move the object.