Mitsubishi RV-6SDL Robot arm Servo/Encoder usability
16 Dec 2020 07:03 - 16 Dec 2020 07:04 #192105
by Aciera
Replied by Aciera on topic Mitsubishi RV-6SDL Robot arm Servo/Encoder usability
So after weighing my options I finally moved forward with this robot and it's broken controller. Since dm17ry is an expert on mitsubishi drives and motors and has some pretty awesome insights in the technology used I was able to get the servos running with some used mitsubishi J4 drives.
The original controller:
Had some PCBs made up to interface the drives with the original connectors:
And in action:
The original controller:
Had some PCBs made up to interface the drives with the original connectors:
And in action:
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16 Dec 2020 07:24 - 16 Dec 2020 08:26 #192106
by Aciera
Replied by Aciera on topic Mitsubishi RV-6SDL Robot arm Servo/Encoder usability
The whole affair now looks like this:
After dm17ry kindly merged his branch with the switchkins branch I was able to bring in my config with the vismach simulation and the genserkins setup for my robot arm (forum.linuxcnc.org/10-advanced-configura...nfig-with-simulation).
The driver passes the joints position from the absolute encoders (17bit, 131072 pulses per motor revolution) through to LinuxCNC and automatically sets the axis as homed if the encoder position is valid. This solves the issue of having to rehome the arm every time the system is started, which would have been a major headache.
After dm17ry kindly merged his branch with the switchkins branch I was able to bring in my config with the vismach simulation and the genserkins setup for my robot arm (forum.linuxcnc.org/10-advanced-configura...nfig-with-simulation).
The driver passes the joints position from the absolute encoders (17bit, 131072 pulses per motor revolution) through to LinuxCNC and automatically sets the axis as homed if the encoder position is valid. This solves the issue of having to rehome the arm every time the system is started, which would have been a major headache.
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21 Dec 2020 07:48 - 21 Dec 2020 07:49 #192611
by Aciera
Replied by Aciera on topic Mitsubishi RV-6SDL Robot arm Servo/Encoder usability
Made a first video with a tentative test:
user-images.githubusercontent.com/460672...7d4-24273a026c54.mp4
user-images.githubusercontent.com/460672...7d4-24273a026c54.mp4
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22 Dec 2020 15:40 - 22 Dec 2020 16:00 #192821
by Aciera
Replied by Aciera on topic Mitsubishi RV-6SDL Robot
Made a new video to show World - vs Tool-coordinates:
user-images.githubusercontent.com/460672...e1a-eaa703d26b18.mp4
[edit]
This is the GCODE that is running in the video:
[edit2]
And here is the python remap for the "G91.2" command used in the program. I'm a clumsy programmer so it's probably a mess to somebody who actually know what he's doing and also likely why the rotations don't work properly
[edit3]
Note: I don't claim to have come up with the python script all by myself. I usually shamelessly copy/paste and modify what I can find on the net. So if anybody recognizes parts of it please leave a comment. IIRC I heavily leaned on work by Rudy du Preez.
user-images.githubusercontent.com/460672...e1a-eaa703d26b18.mp4
[edit]
This is the GCODE that is running in the video:
Warning: Spoiler!
[edit2]
And here is the python remap for the "G91.2" command used in the program. I'm a clumsy programmer so it's probably a mess to somebody who actually know what he's doing and also likely why the rotations don't work properly
[edit3]
Note: I don't claim to have come up with the python script all by myself. I usually shamelessly copy/paste and modify what I can find on the net. So if anybody recognizes parts of it please leave a comment. IIRC I heavily leaned on work by Rudy du Preez.
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26 Dec 2020 10:49 - 26 Dec 2020 10:49 #193216
by Aciera
Replied by Aciera on topic Mitsubishi RV-6SDL Robot
A little update:
I found a solution for mounting the DELL Optiplex and Dmitrys PCI board connected to the miniPCIe through an adapter. I had some trouble getting the PCI adapter recognized but it was all resolved after a BIOS reset.
The idea is to be able to fit everything into a 600x400x300mm metal enclosure.
I had a bit of a setback as I crashed the 4th joint into it's limits while trying out a new version of my python script. It still works but it clearly has taken a hit as it now needs a lot more torque to jog and it sounds a bit rough when moving it at higher velocities. So this led me to reconsider my approach and while the arm didn't cost me that much I don't want to wreck it by doing something that could be prevented.
While the soft limits were working fairly reliably before the motion planner clearly missed to prevent the crash that came after the A angle value switched from positive to negative value which led to the forearm twist at maximum speed.
I decided that before running code on the real arm I need to run it in a simulation.
I found a solution for mounting the DELL Optiplex and Dmitrys PCI board connected to the miniPCIe through an adapter. I had some trouble getting the PCI adapter recognized but it was all resolved after a BIOS reset.
The idea is to be able to fit everything into a 600x400x300mm metal enclosure.
I had a bit of a setback as I crashed the 4th joint into it's limits while trying out a new version of my python script. It still works but it clearly has taken a hit as it now needs a lot more torque to jog and it sounds a bit rough when moving it at higher velocities. So this led me to reconsider my approach and while the arm didn't cost me that much I don't want to wreck it by doing something that could be prevented.
While the soft limits were working fairly reliably before the motion planner clearly missed to prevent the crash that came after the A angle value switched from positive to negative value which led to the forearm twist at maximum speed.
I decided that before running code on the real arm I need to run it in a simulation.
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