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Align Z axis of TCP
#1
Hi, we are trying to create a camera path with our ABB 1600 and external track. We have it following a curve and reading the normals from a surface. However the z axis rotates as it moves tilting the camera. Is it possible to constrain the y-axis so that it can only rotate around the x-axis (perpendicular to the grounds x-axis). We will be generating the paths in Rhino and Grasshopper. I have started to play around with creating points, and creating  surfaces for each point and aligning those, but so far the camera still points in the right direction but rotates around the normal. I have tried reducing the 'Allow a tool Z rotation' to 0, but then it can't compute the path.  I have attached a simple path that tracks and pans but it will also need to tilt +/-90deg. Any guidance would be appreciated.


Attached Files
.rdk   RoboDK_CameraPath_Template_V4.rdk (Size: 4.17 MB / Downloads: 9)
#2
Hi Fabricationlab, 

I took a quick look at your station. 
Here are a few changes needed. 

1 - Set the linear rail compensation in the right direction with respect to the robot base. In this case, the rail is moving along the Y-axis of the robot and by default, RoboDK considers a movement along the X-axis. 

You can change that globally for your project or locally for each Curve Follow Project. 
   

   

2 - You also need to change some settings in the Curve Follow Project to manage the orientation. Pressing Z+ is the most important one as the Flange is on top of the path. 

   


I attached the station with my modifications.

Hope it helps. 
Jeremy


Attached Files
.rdk   RoboDK_CameraPath_Template_V4.rdk (Size: 4.17 MB / Downloads: 11)
Find useful information about RoboDK and its features by visiting our Online Documentation and by watching tutorials on our Youtube Channel


#3
Hi Jeremy,

 Thank you for helping. What you suggested was a great help and it worked for the example I gave. I tried with a more complex curve and i got it down to +/-10deg z orientation. Is it the curve that is that is the problem (I don't think it is as ambitious as our students will be), or is it not spending enough time computing the path, or is the position of the camera in relation to the flange. Any pointers would be a great help.

best

Ed


Attached Files
.rdk   RoboDK_CameraPath_Template_V6.rdk (Size: 4.09 MB / Downloads: 10)
#4
Hi Ed, 

The answer is a bit of A and C.

You are now facing one of the most common issues in the field of robotics, singularities. 

The first section of the path has a switch of orientation from down to up. This creates an alignment of joints 4 and 6 and mechanically prevents the robot from running a linear motion between the 2 points. 

   

The solutions would either be to avoid crossing the plane, change the position of the curve, the orientation of the Camera with respect to the flange or change the starting configuration. 

Have a great day. 
Jeremy
Find useful information about RoboDK and its features by visiting our Online Documentation and by watching tutorials on our Youtube Channel


  




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