Wrist singularity issues for ABB robot config
@Anonymous
Without knowing exactly what toolpath you are analysing it is quite hard to comment and give you a specific solution that works.
One thing I recommend is to use the singularity avoidance on multi axis curve type toolpaths ONLY. It is better suited for smaller toolpaths.
If you are milling (roughing/finishing) I would recommend using a Tool constraint, either fixed orientation or orientation vector (can be edited locally). It will be faster to reach a valid solution as the orientation is fixed throughout the entire toolpath. The "Automatic singularity avoidance" is really for simple toolpaths due to the way it works.
The automatic wrist singularities avoidance is very specific, but if you want to see it in action I recommend opening the project named "SingularitySquare1" located here C:\Program Files\Autodesk\Autodesk PowerMill Robot Plugin 2020\Library\Projects
once the project is open:
- load cell named "R2-6X-Spindle30+StaticTable" from the Autodesk robot brand
- activate the first toolpath , simulate and save simulation file (no tool constraint option)
this toolpath should give you a singularity due to the 30 degree end effector, as it keeps axis 4 and 6 aligned throughout the entire toolapth.
- activate the second toolpath, select the "Automatic singularity avoidance" and simulate
the end result is a singularity free toolpath.
The reason it works is because the simulation solver tries a different angle (rotation around Z axis of tool) as soon as it finds a singularity. It tries to simulate the entire toolpath with the chosen angle, if that fails it increments the angle again and tries to simulate. For a simple toolpath the algorithm is successful at providing a solution. For a On larger toolpaths it might keep incrementing every time it finds a singularity and thus reaching another issue (axis 5 limit) before it solves the entire toolpath. So for this I recommend using it only on simple curve toolpaths.
I believe you would benefit from going through some of our training documentation and learning what methods exist for avoiding axis limits and singularities.
Please open C:\Program Files\Autodesk\Autodesk PowerMill Robot Plugin 2020\Help
Go through "PowerMill Robot - Training Manual.pdf"
page 38 - Creating a Robot Program will detail how to use Orientation Vector [X] - Vector constraint to maintain a fixed orientation of the X axis of the Tool workplane. This is the easiest way to a valid simulation with no issues.
page 61 - Orientation vector is another option, you can create a fixed orientation in the toolpath and edit locally if required.
Again, without details of the toolpath type & settings, size of part, size or Robot etc I cannot comment more on your errros.
But Error1.png normally refers to a toolpath that a robot cannot reach, if you had the "Automatic singularity avoidance" on it could be a reachable toolpath if you had a fixed head angle.
Error2.png indicates that not all the toolpath points were simulated correctly, so the simulation file might not contain all toolpath points. This is important to note, never post process a toolpath as it might be missing a point that can cause issues like collisions etc.
I hope this helps you investigate your issue.
let me know if you make some progress on this.
Alex
Alexandre Pinto
Process Specialist
@Anonymous
Without seeing the project, I would try the following:
1. Try recalculating the toolpath with orientation vectors on. Hopefully this solves the first error.
2. For the other errors, I feel like the part is too far from the robot. Try bringing it closer.
If you can share the PowerMill project, that may help us determine what the actual cause is.
Christopher Marion
Technical Specialist - CAM
SolidCAD - Canada
Technical Specialist - CAM
SolidCAD - Canada
@Anonymous
What is the part position location from the base? Currently, the part sits underneath the robot base with workplane 1 being applied.
Christopher Marion
Technical Specialist - CAM
SolidCAD - Canada
Technical Specialist - CAM
SolidCAD - Canada
Accepted solution
@Anonymous
I edited your toolpath and changed the point distribution.
Output Type = Redistribute
Tol factor = 1
tick point separation distance
maximum distance = 100 (mm)
untick point separation angle.
Calculated the toolpath and simulated, and I had no issues at all.
The reason you had issue are simple.
- the tool Z axis aligned to the 6th axis is great at aligning the 3 axis responsible for wrist singularity (axis 4, 5 and 6). I thought I had made it clear previously.
- the lack of point means the simulation solver did not do a good job at defining the robot posture at the edges of the part. You only had points at the corners, so always a good idea to "help" the solver by adding points
- the position orientation of the part is again ideal for singularities and axis limits.
if you are going to keep this configuration of teh hardware you will always have issue that is for sure.
solutions:
- change point distribution (add more points)
- instead of vertical toolpath edit the tool axis to have a lean/lead angle, that will force axis 4, 5 and 6 NOT to be aligned
- think of adding an angle to the end effector/spindle (so you reduce alignment of axis axis 4, 5 and 6 )
- think of changing the part position (location/orientation)
luckily it is easy and fast to make all these changes inside PowerMill, and you are able to see end result quite fast.
Is this clear ?
Can you replicate what I did and also get a successful toolpath without issue ?
Alex
Alexandre Pinto
Process Specialist
Accepted solution
@Anonymous
I followed @alexandre.pintoAGNAU advice with adding points to the toolpath and it worked perfectly.
Since you are just starting with PowerMill, modifying the point information of the toolpath is located within the strategy form. Just right click on the toolpath in the Explorer and click on "Settings". That will open the toolpath form back up. Then select the Recycle icon and the top left corner of the form to access the parameters.
To follow Alex's recommendations, go to the Point Distribution page. Fill in the information and Re-calculate the toolpath.
Christopher Marion
Technical Specialist - CAM
SolidCAD - Canada
Technical Specialist - CAM
SolidCAD - Canada