scurve trajectory planner

More
1 year 8 months ago #320830 by automata
Replied by automata on topic scurve trajectory planner
Hi Grotius,
maybe the biclothoid library stuff you and andrew2085 developed in a previos thread is awesome.
forum.linuxcnc.org/38-general-linuxcnc-q...ruckig-lib?start=350

Maybe that can be used for filleting. And since we can calculate the length of a clothoid given its start and end curvature, maybe it can be used for the S curve trajectory generator more easily and without approximating the arc length.

Thanks for working on this hard problem.
-automata
The following user(s) said Thank You: Grotius, Beef

Please Log in or Create an account to join the conversation.

More
1 year 8 months ago #320832 by Grotius
Replied by Grotius on topic scurve trajectory planner
Hi Automata,

andrew2085 was very helpfull. It was hard to get his code to work properly.

We have a robust clothoid 2-dimensional library.  
For now it lack's the 3-dimensional clothoid implementation.
github.com/ebertolazzi/Clothoids/issues/45
I am unable to create the 3d clothoid from his comments.

A clothoid needs a iteration ~20  to find optimal fit. This is also the case at a runtime interpolation when u
use the clothoid library in a standard way.

The new approach is time optimal. By this i mean the "arc-strip" method for curves of any type.
The new planner's infrastructure makes it easy to add new trajectory smooth algo's. So almost anyone can
add a algo to it. Sinds it also has a algo template.

Using a clothoid is a very good approach, i agree 100% with that.

Downside is that the real deviation is hard to find. Then 2 attached clothoids could do exact deviation.

When optimizing the path at load time, the clothoid is constructed (~20 clothoid iterations are done) and clothoid is
saved as arc_strip to be interpolated as fast as can be later on.
Soon i wil test a clothoid this way.

Julian made a test environment to test multiple cnc files in a loop. The velocity's are extreme.
We had scurve hang's in certain cases early'er this week. After figuring out, we had some isnan values coming up so now and then.
Isnan = is not a number. This can happen when dividing to zero for example.

We decided that the planner has to first pass test bench, before going any further writing smooth algo's on top.

Let's run the test environement for a few more hours. image missing /media/kunena/emoticons/wink.png


 
The following user(s) said Thank You: akb1212, tivoi, Aciera, Darium, Beef, Unlogic

Please Log in or Create an account to join the conversation.

More
1 year 8 months ago #320906 by Grotius
Replied by Grotius on topic scurve trajectory planner
@Coyote,

Great news. Just some clarification: is this planner based on your work or it is based on Ruckig Lib with user @Beef : "That's why Grotius and I have decided to start this new project ...." ?

The planner is not based on Ruckig Lib. And Beef is still in contact with us.
Beef has done his Master Degree in the mean time. image missing /media/kunena/emoticons/smile.png

The intention once was to use the Ruckig lib. Ruckig is not free in use when you want to calculate trajectory waypoint's,
want to use endvelocity's at waypoints etc.

To overcome this problem, we use our own scurve implementation based on science paper.'s
And the scurve code is open source and free to use.

It just runned a test bench at Julian's place for 13 hours without any conflict.
 
The following user(s) said Thank You: Coyote, pommen, tiagounderground, Darium, Beef

Please Log in or Create an account to join the conversation.

More
1 year 8 months ago #320925 by ihavenofish


Beef has done his Master Degree in the mean time. image missing /media/kunena/emoticons/smile.png

Beef mostly just mutters in the corner these days about everyone being jerks...


*tries to start some forum beef*
:P



 

Please Log in or Create an account to join the conversation.

More
1 year 8 months ago #320937 by juliankoenig87
Hi.
So, I tested the scurve with my loop machine for over 18 hourse. No crashes. And I really try to torture it with extreme values. I would call it a sucess and really good coding by Grotius. Well done.

I will go on and do some tests and thinking of backlash compensation this weekend. Have some thoughts but have to figure it out first.
The following user(s) said Thank You: tommylight, Beef, Unlogic

Please Log in or Create an account to join the conversation.

More
1 year 8 months ago - 1 year 8 months ago #320939 by Beef
Replied by Beef on topic scurve trajectory planner
@Coyote no I didn't have any role here. This is all Grotius' genius on display. I got buried under school responsibilities and managing now two businesses so I haven't been too active in machining over the last year image missing /media/kunena/emoticons/sad.png

@ihavenofish this is beyond dad joke into grandpa joke territory image missing /media/kunena/emoticons/laughing.png

@Grotius I have tested the scurve on my machine for motion (although I haven't tested probing/toolsetting/cutting). I somehow managed to destroy a spindle bearing a while back and turn it into a spindle bushing, and I just got a new spindle earlier this week - I should have time to install the  VFD into the electronics cabinet next week and set up the new spindle, and will send some videos of cutting differences once that's done.
Last edit: 1 year 8 months ago by Beef.
The following user(s) said Thank You: Coyote, Grotius

Please Log in or Create an account to join the conversation.

Time to create page: 0.390 seconds
Powered by Kunena Forum