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Weird robot behaviour

#1
Hello everyone,
I'm facing this problem since 3 days ago, I'm using the same targets that I've been using for a while now, and for some reason I'm getting this result a bunch of times (not always, that's the weird thing!)

[Image: zfyu1Tr.png]

For some reason the robot "moves to a target" like this, resulting in target reach errors at the moment of reaching another target...

The way that i'm getting the targets is with a target and Joints() in python...

Some clues:
  • If I press home or double click into another target, it will solve, but its kind of annoying to have this error at random moments in a simulation.
  • If I start the simulation again without solving this "absent end effector" the simulation will never solve it (I HAVE to manually click another target or something to keep working with the simulation)
  • It's not something that happens constantly, sometimes with the same target fails and sometimes it works
  • At the beginning I thought it was because I was using this "Fast simulation" button, but apparently it works with the normal speed as well
  • As an example, the joints of the target that I'm using now are: [3.866689730073942e-15, -34.97000000000012, 49.98000000000021, -180.0, 89.98000000000012, 4.899999999999999]

I've found that the function Joints() sometimes gives me [0] as an output and its totally random... and this is when the end effector behaves like this
Why can this be happening?
#2
Sometimes I even see that I got random values at some points...
these are the real targets:
[90.06959930874842, -31.357419995960772, 48.86132893169375, -179.98196916229745, 92.50391938001054, 4.933559954336468]
[3.866689730073942e-15, -34.97000000000012, 49.98000000000021, -180.0, 89.98000000000012, 4.899999999999999]
[-90.08322292664911, -38.62963502214158, 50.599363065999086, -180.02207805910126, 86.96985109152055, 185.06156270680367]

I acquired them by using the "target.Joints().list()" function, all 3 one after the other
and so far I've acquired this values (without any change on the code or the robodk file):

[90.06959930874842, -31.357419995960772, 48.86132893169375, -179.98196916229745, 92.50391938001054, 4.933559954336468]
[-68.44720797516314, -27.107083175689333, -123.57254432675144, -185.66612006158945, 105.22709451881367, 24.28729846069518]
[-44.08620666946378, -16.097001155342777, -139.78721242566786, -169.35049938840405, 103.00130532726904, 144.30815567574052]

[90.06959930874842, -31.357419995960772, 48.86132893169375, -179.98196916229745, 92.50391938001054, 4.933559954336468]
[0]
[0]

[90.06959930874842, -31.357419995960772, 48.86132893169375, -179.98196916229745, 92.50391938001054, 4.933559954336468]
[115.55605522238929, 12.547905540790575, -25.99433021314654, -6.423217595211129, 89.83045092467604, 29.70746207712574]
[-35.635014353035416, -7.102990669218356, -150.65863510476302, -171.19714795076837, 99.83751487292083, 151.7958193960372]

[90.06959930874842, -31.357419995960772, 48.86132893169375, -179.98196916229745, 92.50391938001054, 4.933559954336468]
[-70.03072682216714, -37.59967789889643, -106.84611524593066, -185.45467364787416, 111.30225692231483, 22.250798029091534]
[-47.58264685790497, -21.62606374374492, -132.3805777991316, -168.56651998410103, 105.4506513062006, 141.47198329861536]

I've also realized that the first target is always correct but the others 2 are random
#3
It looks like you are trying to move the robot to invalid locations (robot joints out of reach or a pose out of reach).

When this happens you may get an empty array [0] when you request the robot joints.

It would be great if you can provide a RoboDK file and a Python script for us to reproduce this. If it is an issue or a bug that we can reproduce we can quickly fix it.
#4
But why it doesn't fail all the time but only a couple of times? It's a pretty "simple" target, not even close to singularities :/
#5
Please provide an example that we can reproduce. You may be accumulating calculation errors that turn into unreachable targets.
  




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