I was thinking about quad esc and came up with a question

[G+_610GARAGE]

I was thinking about quad esc and came up with a question. Why are we still using rc escs? I can understand why people started to use them. They are cheap and readily available. But now, why haven't we replaced them with simpler H bridges, and let the flight controller modulate them.

 

If the flight controller could control the motors directly (through something like an H bridges obviously) you could do a lot of neat stuff. For example, torque limiting. You could run the system at a higher voltage and have the controller limit the amount of amps the motor can draw. This way the motor can give sudden bursts of power (like when the prop needs to drastically change speed) and then limit the current to prevent the motor from overheating. I think that the flight controller could also monitor feedback from the motor coils and detect when the motor is stalled out. Then cut power to that motor (I'm thinking if you get caught in a tree, not in mid air). Having the flight controller directly manipulate the motors would also reduce latency, since there isn't another ic getting in the way.

[G+_Fr. Robert Ballecer, SJ]

This was my first design for a DIY speed controller, but I abandoned it because MY design was:

 

1. Most costly than an ESC (BLDC)

2. Weighed more than an ESC

3. Didn't seem as dependable as an ESC

 

Because most MR motors are 3-phase, in order to get an appropriate amount of voltage and current through them (For example... 15v 100amps) you would essentially need to build out a board with several H-Bridges per channel, with FETs at the ends.

 

Now that's MY crappy design, and I'm not good with electronics... at all... but my take was that they just didn't scale as well as BLDC when you started switching INSANE amount of current. 

[G+_610GARAGE]

Fr. Robert Ballecer, SJ Yea, thats kinda the downside with quads. Any home made electronic will be a lot heavier than storebought. Especially when it comes to high power devices. But just out of curiosity, did you ever try desoldering the controller ic from a store bought esc and try to interface directly to the onboard H bridges?

 

But why haven't manufactures made an esc to be ran directly by the flight controller. I wonder if it is a chicken and egg problem. The flight controller needs to be able to do it, but there's no need to add the functionality because there isn't an esc to take advantage of it. Or maybe they never thought of it.