Robotics and ROS 2 Essentials

Ros2's colcon will build the packages in your workspace individually, in topological order of the dependency DAG. This is a completely insane way to structure a c++ build because it destroys the innate parallelism of the compilation process.

The build system for ros1, catkin, didn't have this problem because it turned all your packages into a single cmake build. Just one of the many ways that ros2 was a regression from ros1.

i am dealing with ros these days for calibrating my custom hardware. it really is gROSs.

Thankfully, I have fully isolated ROS parts into their own dockerfiles.

Robotics is very different from CS. At CMU robotics is huge and consists of thousands of researchers, with dozens of classes a MS student would have never encountered during their CS PhD or undergrad. It's true you can learn robotics from books, but CMU or any grad program has access to robotics hardware resources you can't find online or in the library. For example I took a course there that had the Aldebaran Nao as a platform. The course has a dozen of them, at the time they were worth $20k a piece.

Well, if 9/10 of a thing is a dumpster fire, would you expect the last 1/10th to not be?

We have a handful of devices built on STM32, RP2040, RP2350, RP Pico and RP Pico-W running bare metal firmware and green threads for task management.

These were generally designed to communicate over UART (to a physically-connected host) or a LAN (wired or wireless) using MQTT topics and plain text message formats.

We have a primary, core machine built around Linux SOMs like NVidia's Orin or the RPI5, which could run real software (like ROS).

I expect to have dozens and eventually many hundreds of nodes in a variety of facilities.

So far, things were going pretty well, though very sparse in terms of tooling. For example, I've got a makeshift midi controller (for physical knobs) that uses a Python script, debug connectors, and messy gnuplots to do PID tuning.

I got pretty pumped about the Foxglove Studio product and pulling on that thread led me into the (completely awesome) YT channel "Articulated Robots" (https://www.youtube.com/@ArticulatedRobotics), which led us down a path to seriously considering a move toward ROS2.

I wrote it off a couple years ago (2021/2022-ish) for a handful of reasons:

a) The move from ROS1 to ROS2 triggered my PTSD from my time at Google where everything had 2 versions: One that's deprecated, and One that's not ready yet. It also triggered trauma from Python's ongoing and complete disregard for backward compatibility.

b) It's obviously designed to run on Linux, but I have a bunch of low-cost bare metal micros driving around. What the hell kind of robotics platform doesn't (by default) run on microcontrollers?

c) CMake is already one of the absolute worst piles of trash I've ever encountered in nearly 25 years of software development. Wrapping CMake (twice now!?), which is already a crap wrapper is so obviously such an awful idea that it's tough for me to trust anyone who had part in that decision.

d) C++. No thank you. Slow builds are a non-starter. C is fine IMO.

Now, I've spent 4-5 days watching videos, doing tutorials and bringing up ROS2 topics and basically fiddling around with it and just learned that Google(ish) bought the core team, which has me deeply concerned about the future of the platform.

I'm actually still kind of interested in the DDS portion of ROS2, but the whole mess trips my spidey sense and has me feeling like dragons be lurking.

Seeing this thread with so many people speaking so negatively about it has me desperately wanting more information.

Can anyone point me to anything that presents concrete problems and (better) alternative systems that work?