How can I download source code?

My interest at present is to read the source code to see if I can find some code I need to properly control a closed loop hydraulic system with S-curve positioning to maximize travel speed while minimizing backlash. I suspect some piece of code in your project does that. How can I look at it? Thank you.

PS: To anyone who would say, "read the documentation" I refer you to my post here in Documents thread and I ask for a genuine answer. Thanks.

If you want a quick look on the web :
git.linuxcnc.org/gitweb?p=linuxcnc.git;a...;h=refs/heads/master
click on tree and you see the file system of linuxcnc.

If you want to peruse the source on your computer I would recommend using GIT to contain it:
wiki.linuxcnc.org/cgi-bin/wiki.pl?Git#Pr...development_with_git

In fact linuxcnc doesn't use S curve trajectory planning, it uses trapezoid planning.
It also doesn't have look ahead, though that is being developed right now. (not sure if that is important for your use)

If you explain your use more, others may help you pin point your search.
If you are not interested in using Gcode to control the hydraulics then HAL is what you want to concentrate on.

Chris M

I found it! The github mirror has the zip download button.

While S-curve would be nicer, trapezoid will work.

My project is not a CNC mill or lathe but a robot. I've used G-codes on a MaxNC and manually to design and check a printed circuit board before it was made - so I know a lot about it. I'm not sure that's what I want for the robot but it's currently an option for the communication layer

What I need is to convert the trapezoid code to work on a Parallax Propeller microcontroller. Then I'll be controlling that via a Raspberry Pi. The microcontroller has more IO pins but the software isn't quite as flexible as on the Pi.

One tough problem I need a tip on is how to counteract gravity when a robot arm swings down under trapezoid control. I've found if I have lots of weight on the arm (250 lbs) it goes down fast regardless of what I tell the electronics. So it would almost seem I need a way of detecting the position and when it gets near the end of travel down, it should slowly ramp in the up direction until it stops. Not familiar with that yet.

To be frank, what I'm shooting at is to enter the DARPA robotics challenge next December. If you look at their website, you'll see 90% of what I want to do, less a few ideas I have to speed mine up. Unfortunately I'm not funded with millions, I'm quite the opposite, barely above food stamps. So that's why I'm looking for free code even if I have to translate to Parallax's Spin language.

The wiki has a few gems in it. some are out of date but still have good info:

wiki.linuxcnc.org/cgi-bin/wiki.pl?Simple_Tp_Notes
wiki.linuxcnc.org/cgi-bin/wiki.pl?Trapez...e_Trajectory_Planner

What kind of feedback does your robot's joints have ?

Chris M

Also linuxcnc works on the bbb if that is an option for you.

Thanks, I have a Raspberry PI on hand but am waiting for a video converter to VGA. The Beagle Bone is next on my list if the Pi comes up sour.

I looked at the HAL code and I'll probably get more out of this link you posted. Thanks.
wiki.linuxcnc.org/cgi-bin/wiki.pl?Trapez...e_Trajectory_Planner

But I may end up doing a lot of code studying and writing.