Position Control of dc motor with encoders

@byron 

I expect a roving bot may not be able to keep 2 beacons in visually in view as it travels

It wouldn't keep any particular 2 beacons in view. You need enough beacons that it would see at least two beacons no matter which direction the camera was pointing. It also needs to recognize the beacon. All this I have worked out in theory and done simulations but they are in FreeBASIC so I will have to translate them to Python. You can click the desired destination. The robot "looks around" to determine its current location and then computes a path to the desired destination. It simply recomputes the path if it comes across an unexpected obstacle. I can show how that is done in simulation. As it moves it locks onto whatever beacons are visible at the time. It can know that some where on say the left there is a beacon even if it is not in view just as you can. You may be looking at your computer screen (a possible beacon) and know that if you turn around you will see the door (another possible beacon). I have a map of the house accurate to at least 1/2 inch. I know robots can create maps using LIDAR (or vision) but that will have to wait. It all has to be done module by module.

but I need you to speed up a bit on your project

I know that and believe me it is frustrating getting the hardware working and then writing the code to handle the hardware which unlike a simulation has issues. I spent hours trying to figure out why a program wasn't working only to realize that I had in the new build incorrectly connected two of the PWM wires to the L298.  Today (yesterday it is 2:45am as I type this response) the motors were not behaving properly and I still can't figure out what is wrong. I rebuilt the webcam robot base and have done something wrong somewhere. Another problem is the USB connection is not being recognized by the PC. I have to wiggle it to get it to connect and then it drops out again.

To be honest weeks and often months go by without me doing anything choosing by necessity or choice to do something else. Even if this forever project never gets completed I do enjoying working on it when in the mood.

Building a real or useful robot is expensive and hard as Bill indicated years ago and he also indicated he didn't want to do it alone and he is an electronics expert with access to hardware and a workshop I don't have thus my "wood" creations and salvaging of robot vacuum parts.

https://dronebotworkshop.com/build-a-real-robot/

"A robot like this is not a trivial project, far from it. To build it requires skills in mechanics, electronics and programming. We will be working with machine intelligence and other esoteric fields of study.

And I really don’t want to do it all alone."

Regarding outdoor robots GPS would be an essential part of it. If you google videos on delivery robots you will see how much technology is involved.