Messages

11

CS-Lab / Re: Jerky movements in complex toolpaths.

« on: July 22, 2016, 11:35:25 AM »

So yaskawa doesnt have a lot of data on these drives. they are cpcr mr-052 nb drives. I have long suspected that they were not a +-10v drive. I confirmed my suspicion today when I spoke to a company on the east coast here in the states that repairs them. They are actually a +-12V drive. I don't think this should be such a big issue though, right? Just lower acceleration rates and lower max velocities?

12

CS-Lab / Re: Jerky movements in complex toolpaths.

« on: July 22, 2016, 11:02:28 AM »

Nope. No backlash enabled. What should my max following error be in terms of distance when I'm tuning the servos? When I use the autotune function I end up with a max error around 1000 pulses. Since I'm 84666.66 pulses per inch, thats about .011" according to my math. That seems high.

13

CS-Lab / Jerky movements in complex toolpaths.

« on: July 22, 2016, 12:31:09 AM »

Hi,

  I have retrofit a 1979 matsuura mc500v with a cs labs csmio/ip-a ethernet analog motion controller. The machine was originally capable of accelerating at 40in/secsec and 400ipm rapids.

I currently have the acceleration and rapids set at 80% of their normal values.

I have look ahead set to 200 lines, but I have tried all combinations including 1 line and 1000 lines.

I have CV turned to on. All other settings related to CV are off but I have played with the settings ad nauseum.

I have CV feedrate turned off, although I have tried to run programs with it on.

The problem:

When running a toolpath of any complexity, The machine tends to jerk unpredictably at moments peppered throughout the program. It does not cut in a jerky movement through the whole program, just every few seconds and sometimes throughout entire sections of the the toolpaths. These jerks will always happen in the same places in the toolpaths. These jerks will trigger following errors if I do not have my max following error set somewhere around .05" These jerks do not happen when I'm running simple toolpaths, but only when I'm running complex toolpaths with lots of small arcs and linear movements.

My attempts to fix the problem involve:

What works is to run the program at much lower feeds and rapids. This results in a 40 to 50% longer cycle time. Since this is a production machine in high volume production shop, this is not an acceptable solution. I have also set the acceleration rate at half the value that the machine was designed to run at, but this just makes the jerks less prominent. This also results in a rougher finish when moving in arcs and contours. This is also unacceptable. I have also tuned the servos over and over, trying many different combinations in an effort to achieve the perfect tune. The tighter the servos are tuned, the more pronounced the jerks are. I have also uninstalled and reinstalled a different version of mach3. I am currently running V R3.043.062. I have also installed the lastest version of the firmware for the cs labs controller.


My theories:

I suspect that something is driving the servo drives far beyond their configured limit in brief pulses in order to move the machine along to the correct position. It is almost as if mach or the motion controller are ignoring the acceleration limits when moving in small increments along a contour.

Another possibility is that the look ahead function in mach is missing lines of code. Although this sees less likely since the program will be running along smoothly but then jerk in the same spot every time.   


Response from CS labs:

I have recently made a video outlining the problem and posting it on my youtube channel. It can be found here.

https://www.youtube.com/watch?v=VEE7v3ewd3U

CS labs can't seem to figure out the problem.

14

CS-Lab / Re: Jerky movement between strait movements and curves.

« on: June 25, 2016, 12:13:24 AM »

 I have reinstalled mach3 and rebuilt the xml file. I also reinstalled the firmware from Cs labs. I tuned the servos MANY times. I lowered the acceleration rate down to 5/sec/sec which is very low. Still, nothing seems to help.

When the program runs from a linear movement into a circular movement there is a VERY distinctive jerk. The jerk is harder the faster the machine is moving. If I'm moving at 85ipm and my max following error is set high, the machine jerks but keeps moving through the program. If I have my following error set low then the machine just triggers a PID error. If I am running at a higher speed like 150ipm then the jerk is even more distinctive and the machine triggers a PID error. Basically, my machine only works at low feed rates and rapids. I need this machine to move fast for production. Any suggestions?

part of me suspects there is a bug in the controller itself, but I can't be sure.

I'd love to test a bit of code out on another machine running under an IPA if I could.

15

CS-Lab / Re: Jerky movement between strait movements and curves.

« on: June 24, 2016, 07:52:15 PM »

Thanks, Hood! You are, by far, my favorite Scotsman!

16

CS-Lab / Re: Jerky movement between strait movements and curves.

« on: June 24, 2016, 12:31:34 PM »

Tweakie, I just realized that's an FTP link, so I think I just need to wait for you to be online, is that right? Thanks!

Joathon

17

CS-Lab / Re: Jerky movement between strait movements and curves.

« on: June 24, 2016, 10:25:56 AM »

Hi, Tweakie.


That link doesn't seem to work for me. Is there an alternative? Thanks!

Jonathon

18

CS-Lab / Re: Jerky movement between strait movements and curves.

« on: June 22, 2016, 08:01:58 PM »

Thanks Hood. I do have the 066 version of mach. Is there somewhere I could download an older version? Under the download page for Mach3 they only seem to have the 066 version and vista version.

19

CS-Lab / Re: Jerky movement between strait movements and curves.

« on: June 20, 2016, 11:12:40 PM »

Hood,

 I'm not sure. I'm sure my servos could be tuned a little better, but truth be told I've tuned them so many times I'm almost to the point where I'm over it. Back when the machine was missing steps due to the optocouplers they were more difficult to tune, so the new encoders have helped quite a bit. But I think the feedback from the servos to the drives are whats getting me know. I've adjusted the three potentiometers on the front of the servo drive to no avail.

The thing is, I had it running fairly well before I tried to reconfigure Mach for ridgid tapping. In the process of switching the spindle to the control of the ipa rather than the plc, I accidentally deleted my M6 macro and tried to recover it by reinstalling mach3. Ever since the reinstall, the machine has been having trouble. Its like its not capable of look ahead anymore. If I'm running a program at 45ipm and each point is only a few thou away from the next, say in the case of a helical plunge, the machine never has the chance to accelerate to the next point. So while the machine is commanding the drives to move at 45ipm its actually moving at 1 to 3 ipm. CS labs suspects that my mach3 file is corrupt. Don't know how that would happen, but I'll try downloading and reinstalling a fresh copy. I would make the jump to mach4 but rigid tapping isn't supported there and I've grown fond of rigid tapping.

20

CS-Lab / Re: Jerky movement between strait movements and curves.

« on: June 09, 2016, 08:18:58 PM »

I suppose I should have mentioned the obvious. The machine is definitely in constant velocity mode. And all other constant velocity settings are unchecked