Is the SCARA algorithm used in marlin correct? March 25, 2019 04:45AM |
Registered: 5 years ago Posts: 5 |
Re: Is the SCARA algorithm used in marlin correct? March 28, 2019 05:04AM |
Registered: 8 years ago Posts: 76 |
Re: Is the SCARA algorithm used in marlin correct? March 29, 2019 03:42AM |
Registered: 8 years ago Posts: 76 |
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dongxuzhou
I raised this question after a careful reading of the Marlin and GRBL source code. There is no problem with the kinematics solving algorithm of SCARA. But before applying this algorithm to the Plan_buffer_line function, I feel that there is a problem with the Marlin, so I have been looking for developers to discuss it.
I mainly do desktop manipulator, three degrees of freedom and six degrees of freedom.
This problem does not affect the motion effect of the SCARA type marlin, but it is not correct in microscopic logic, which results in non-Cartesian kinematics in the form of machines that are less accurate than those of the Cartesian coordinate system. Thank you
Re: Is the SCARA algorithm used in marlin correct? March 29, 2019 04:13AM |
Registered: 8 years ago Posts: 76 |
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dongxuzhou
I have never been able to contact the main author of marlin. You can of course put the conversation in the forum. I don't know how to contact the original author. I will thank you if you can help me contact the author.smiling smiley
I think it is possible to modify a marlin firmware that is perfectly suited for SCARA or other robotic arm type kinematics. It is mainly to modify the position of the inverse kinematics and the Bresenham algorithm in the ISR to find an algorithm similar to bresenham but suitable for the structure of the manipulator.
Thank you!
Re: Is the SCARA algorithm used in marlin correct? March 31, 2019 09:31PM |
Registered: 5 years ago Posts: 5 |
Thank you for your support!Quote
invent2main
a pleasure, thanks to you if we can make progress the scara process...
How did you contact Marlin contributors?
There's several main contributors in the official repositionery (https://github.com/MarlinFirmware/Marlin)
I think that the best way to have answer is to "pull a request" (https://github.com/MarlinFirmware/Marlin/pulls)
As I said I don't understand all subtleties of the code but the use of this algorithm in the cartesian plan before move to scara/delta plan seem correct: there's a lot of delta type machines that works fine...?
On my prototypes I didn't notice problems on this point; I maybe have some issues on 'synchronism' at high speed between the 2 motors of the arm because of my specific mechanics but I hope solve that with 32bits computation...
Best regards from France