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Robot Operating System – A flexible framework for writing robot software

ros.org

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Re: Robot Operating System – A flexible framework for writing robot software

#41

Post by dimatura »

protomikron wrote: post #12

My experience with ROS has been suboptimal. It's a collection of incompatible, outdated and buggy tools that communicate with each other via a single-point of failure (roscore) using a pub/sub mechanism. Furthermore they use their own build system (catkin, WHY?), define their own IDL (WHY?), use their own dependency system (rosdep, WHY?) and even mess with your Bash environment. I appreciate their effort and it is re…

ROS started development almost 10 years ago. A lot of "high quality" solutions that seem like a good idea now may not have been around that long ago, or were still in nascent stage. Many of the changes in ROS2 are actually about incorporating some of these solutions -- the most obvious example being the switch to DDS for messaging.

Regarding catkin, I actually think it's an OK solution with some nice features. It's mostly a set of CMake macros that work with a certain conventional structure for packages. If you look at some other (newer) C++ package managers out there, like Hunter or FIPS, it's essentially the same idea. And catkin also supports Python code [1]. It's far from ideal, but it's a hard problem. Like many things in ROS, it's a "worse-is-better" kind of solution.

[1] Not as well as it could, re:pip integration and such; ROS2 supposedly has a better solution.

Re: Robot Operating System – A flexible framework for writing robot software

#42

Post by Davidbrcz »

krona wrote: post #32
Davidbrcz wrote: post #25

Earlier quoted context omitted.

I spoke Mikael Arguedas at the 2018 French ROS days (JONAROS) where he gave a presentation about ROS 2 (talks are available online IIRC, in French). During his presentation; he said that most of ROS 1 was engineered before any of today's well known frameworks were available , hence the lot of custom tools. That has driven a major part of ROS 2's design (especially the use of DDS). Otherwise, I have been personally us…

he said that most of ROS 1 was engineered before any of today's well known frameworks were available , hence the lot of custom tools. catkin is built on top of CMake, so that's no excuse.

A robot is made of dozen, if not hundreds of packages. catkin compiles the whole workspace in a single command while dealing with non trivial build dependency between packages, and generates a ready to deploy folder.

CMake has its drawbacks, fair enough, but 10 years ago it was pretty much already the de facto standard build system for C++. What would have used instead of CMake ?

  - Make and autotools (Haha) ? 
  - scons ?
  - completely custom build system ?
  - something else ?
The most painful I had to deal with was my teammates who, instead of creating a brand new package, would simply copy and paste and existing one without fixing the dependencies, resulting in a build that fails if the workspace was cleared.

Re: Robot Operating System – A flexible framework for writing robot software

#43

Post by Symmetry »

carlsborg wrote: post #3

Anyone using this.. what have you built?

Well, apart from adding some fish[1] support to ROS core I worked on these guys[2] at Vecna and they mostly use ROS. A pretty common pattern in commercial use of ROS is to start out with a vanilla setup and replace important nodes with ones you've written to work the way you need them to.

At my current job we don't use ROS but being able to look at the ROS drivers of commercial arms is a big help in making our own drivers.

[1]https://fishshell.com/

[2]https://robotics.vecna.com/

Re: Robot Operating System – A flexible framework for writing robot software

#44

Post by sronors »

dimatura wrote: post #34
mrfusion wrote: post #31

Could someone explain for a new bee. If I’m building a robot why would I use this and not just write a python script running on Linux?

You can use ROS with Python and Linux. In fact, that's a big chunk of actual ROS-based systems out there, with most of the rest being C++ and Linux. For simple robots, you can get away with a simple script. But say, you want to attach more sensors, add some visualization, some logging, etc. Pretty soon you'll find yourself writing multithreaded (not great in Python) and/or multiprocess code, some kind of simple GUI t…

Good points. You also may find yourself wanting to have more than one robot. And then you may want them to talk to each other.

Re: Robot Operating System – A flexible framework for writing robot software

#45

Post by ModernMech »

Davidbrcz wrote: post #25
protomikron wrote: post #12

My experience with ROS has been suboptimal. It's a collection of incompatible, outdated and buggy tools that communicate with each other via a single-point of failure (roscore) using a pub/sub mechanism. Furthermore they use their own build system (catkin, WHY?), define their own IDL (WHY?), use their own dependency system (rosdep, WHY?) and even mess with your Bash environment. I appreciate their effort and it is re…

I spoke Mikael Arguedas at the 2018 French ROS days (JONAROS) where he gave a presentation about ROS 2 (talks are available online IIRC, in French). During his presentation; he said that most of ROS 1 was engineered before any of today's well known frameworks were available , hence the lot of custom tools. That has driven a major part of ROS 2's design (especially the use of DDS). Otherwise, I have been personally us…

I've been hearing about how ROS 2 is going to fix these problems since 2013. I'm not holding my breath.

Re: Robot Operating System – A flexible framework for writing robot software

#46

Post by securityfreak »

protomikron wrote: post #12

My experience with ROS has been suboptimal. It's a collection of incompatible, outdated and buggy tools that communicate with each other via a single-point of failure (roscore) using a pub/sub mechanism. Furthermore they use their own build system (catkin, WHY?), define their own IDL (WHY?), use their own dependency system (rosdep, WHY?) and even mess with your Bash environment. I appreciate their effort and it is re…

Agree. I used to work with ROS during a semester of AI. We had to build a robot that drove itself on top of a roomba vacuum cleaner and used a kinect for vision. I was super familiar with Ubuntu/Debian, but ROS was a mess. The materials we were provided by the course staff was more troubleshooting guides with ROS, than initial setup tutorials. It was a lot of fun, but I couldn’t imagine building something with real-world applications on top of it. Outdated packages. Lots of unpredictable failures. If the original purpose was only prototyping for students, then it works well for that.

Re: Robot Operating System – A flexible framework for writing robot software

#47

Post by protomikron »

Davidbrcz wrote: post #42
krona wrote: post #32

Earlier quoted context omitted.

he said that most of ROS 1 was engineered before any of today's well known frameworks were available , hence the lot of custom tools. catkin is built on top of CMake, so that's no excuse.

A robot is made of dozen, if not hundreds of packages. catkin compiles the whole workspace in a single command while dealing with non trivial build dependency between packages, and generates a ready to deploy folder. CMake has its drawbacks, fair enough, but 10 years ago it was pretty much already the de facto standard build system for C++. What would have used instead of CMake ? - Make and autotools (Haha) ? - scons…

> A robot is made of dozen, if not hundreds of packages. catkin compiles the whole workspace [...]

s/robot/software

Why even have the concept of a `workspace`? I don't think it solves any problem.

Most bigger software projects are built on-top of other software, but most deal with it without having to implement their own build system. I know that CMake is established software, but despite its own horrendous scripting language I find it mostly useful if you want to build cross-platform native software - if you're going to run on Linux anyway, I think there is no point for this indirection.

> - Make and autotools (Haha) ?

You might laugh about these tools, but they build most of your userspace if you're on Linux. And yes they even work on distributions other than Ubuntu.

Re: Robot Operating System – A flexible framework for writing robot software

#48

Post by TickleSteve »

lnsru wrote: post #36
lnsru wrote: post #17

Could somebody, please, explain me what I need in addition to ROS for functional safety. Some certified laser scanner? Do I understand it right, that ROS completely ignores functional safety?

Thank you for explaining this issue. So commercially available robot needs Jetson TX2 (or Wandboard) with ROS and some hardware from safety tools vendor like Pilz or Sick. And the whole safety assessment from TÜV with official certificate. That was helpful!

What market are you looking at? Its all about risk... if you're targeting the medical domain for example, you have a multi-year project just to get thru the certifications. Conversely if you're just looking at creating a toy with limited movement, weight and power then the risk is significantly less.

Get an engineering safety consultant to have a look.

Re: Robot Operating System – A flexible framework for writing robot software

#50

Post by lnsru »

TickleSteve wrote: post #48
lnsru wrote: post #36

Earlier quoted context omitted.

Thank you for explaining this issue. So commercially available robot needs Jetson TX2 (or Wandboard) with ROS and some hardware from safety tools vendor like Pilz or Sick. And the whole safety assessment from TÜV with official certificate. That was helpful!

What market are you looking at? Its all about risk... if you're targeting the medical domain for example, you have a multi-year project just to get thru the certifications. Conversely if you're just looking at creating a toy with limited movement, weight and power then the risk is significantly less. Get an engineering safety consultant to have a look.

Industrial cleaning, machine is slow, but has many liters clean and dirty water inside. Just prototyping it and thinking how to achieve reasonable price. 30-50k is too expensive, janitor is cheaper.
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