Trajectory Planner using Ruckig Lib

Hi,

I have looked into the trajectory planner again. The code is quite well done so far. A nice starting point to go
on with coding.

There are several trajectory planners made so far.
The " scurve_skynet " i think is the nicest to go on with.

The plan is to integrate a linear & scurve motion planner into the trajectory planner.

This is my latest linear motion library, " linear_motion " wich is now loaded into the trajectory planner at
this  line.

For calculating arc speeds, the idea is to use the "angular_motion " library. The angular motion is loaded into
the the trajectory planner at this line.

I hope within a few day's i can present a new scurve_motion libary.

To update my latest post : I hope within a few day's i can present a new scurve_motion libary.

I have been coding for a while now, coding a new scurve library in c.

The first part is working is now.

This includes the jog part for Linuxcnc.

When user press the jog button, the joint or
axis starts to move, when jog button is released, the jog will slow down and stop.

In the lcnc source i also solved a jogging bug in axis.

This scurve library uses only "jerk-max" to specify the s-curvature part.
In relation to the Ruckig library, this library uses a linear acceleration stage between the convex and concave curve
parts when needed.

In this video we show the scurve velocity when jog button is pressed or released.


I hope you like it so far.

I just want to let you know that this work is really appreciated <3

Hi Routerman,

Thanks for your kind words !

The jogging of a scurve is quite complex, you can find out in the source code.
It took a lot of time and disipline, but for now i am satisfied.

At this moment the jog library is working more or less ok.
Todo is jog step, like jog 1mm, or jog 10mm etc. This you can select in the axis gui.

In linuxcnc this is just jogging to "pos_cmd" and stop there with end velocity zero.

Video shows jogging forward & reverse, and how multipe button presses are being processed as jog interupts.


The scurve-jog project on github includes a c & c++ inplementation. The c part is for linuxcnc.
You can play with the scurve-jog-plot to show the jog curve in a qt realtime plot

Now i will test the jog source code in linuxcnc, and see what the scope displays.
Next update here will be about the linuxcnc scurve jog test.
 

Hi,

It took a long time, but finally the scurve jog library works for linuxcnc including jog-step.
Jog-step is to move a certain distance each button press.

Therefore the scurve library needed a position & velocity control mode.

Next i will try to compare the difference in time performance between the ruckig and scurve library.
This is always nice to know.

It is still possible to select ruckig or scurve in the source code here.

github.com/grotius-cnc/scurve_construct/

Later on in the video the jog-step is shown.


 

When jogging in linuxcnc, we logged the time for both ruckig and grotius-scurve in 2 sessions.

Grotius-scurve session:
Function duration: 10329 nanoseconds
Function duration: 2194 nanoseconds
Function duration: 2515 nanoseconds
Function duration: 6766 nanoseconds
Function duration: 1884 nanoseconds
Function duration: 1764 nanoseconds
Function duration: 5985 nanoseconds
Function duration: 2053 nanoseconds
Function duration: 1823 nanoseconds
Function duration: 8252 nanoseconds
Function duration: 1510 nanoseconds
Function duration: 1358 nanoseconds

Ruckig session:
Function duration: 21779 nanoseconds
Function duration: 9161 nanoseconds
Function duration: 10252 nanoseconds
Function duration: 20288 nanoseconds
Function duration: 8817 nanoseconds
Function duration: 10302 nanoseconds
Function duration: 52762 nanoseconds
Function duration: 42609 nanoseconds
Function duration: 32094 nanoseconds
Function duration: 24196 nanoseconds
Function duration: 41582 nanoseconds
Function duration: 32464 nanoseconds
Function duration: 45580 nanoseconds

This is good news.
Also the grotius-scurve is in principle a more powerfull scurve wich includes a linear acceleration stage between
the concave & convex curvatures, where the ruckig curve is like a spline with no linear stages possible.

Next thing to do is integrate the grotius-scurve into the linuxcnc motion planner.
The first integration is without any look ahead. Where the motion starts and stops every gcode line.
When this is working, we will work on the look ahead, and test the  angular motion "arc" speeds.

So far so good.



 

Bravo you just unstoppable cheers to you ......

Grotius the MVP . I dont know about others, but i would be happy to donate to the further development of s curve in the motion planner.

Hi Routerman,

I hope Tommylight can open a "non profit" bank account in Kosovo for forum donations.
It will certainly help to cover the forum costs, server costs, forum day's.

Hi,

A little update.

I already cleaned up the trajectory planner code, and can start from a clean code template.
Parts of the code is still there. Only the motion part has to be renewed.

Today i added end velocity to the scurve library. Without this each motion should end to zero velocity.
This end velocity option can be used in the trajectory planner's look
ahead function involving path rules. Some gcode motion transitions may contain a end velocity.

Attached a test video that run's a few motion commands using a velocity end value.
It's important given a end position and a end velocity,  the motion finishes there.