[emireles_moldesfrontera_com]

Hello everyone!

I hope you are doing well. I had a question regarding building custom robots from a STEP file, I have followed the tutorial Model your robot, and visited several forums, but I cannot seem to make all of the joints of my robot rotate correctly. I attached the station I made from the STEP file I use, the things is when I try to input the dimensions according to the robot drawing, they seem to be incomplete or incorrect, here is the Robot Datasheet, I asked the clientabout them and they sent me the attached photo with dimensions in red, which I also think is incorrect.

   

The following photo shows how it looks when I try to use the parameters they sent me, the robot is not even aligned.

   

When I try to do it following the measurements I did on my own using Solidworks meaning d1= 345.762, a2= 0, joint 1 and joint 2 rotate correctly, the others ones do not, but I measured other dimensions and I believe to be a3 = 450 mm, the other ones I am not sure about but the client claims they are:  d4: 425.500 and d6: 114.500. I have been scratching my brain as to how to do this, but I still have nothing.


Here is a photo of my robot, as you can the base reference frame I used is at the bottom of the robot with the correct orientation and z axis going into it, I know it may have something to do with the reference frames of each individual object, but I splitted STEP file in robodk, I am not sure how I should approach changing the reference frame of each object. I would appreciate it if someone has any input on the subject, let me know if I am missing any relevant attachments. Thank you.

Best,
Estefania Mireles.

   

Here is my station


  SZGH-T9905.rdk (Size: 86.45 KB / Downloads: 28)

[Olivier]

When creating a robot in RoboDK, its important to have the robot homed in the same position as in the create mechanism picture, or else the physical robot will not match the mathematical one.

   

[emireles_moldesfrontera_com]

Hello Olivier,
Thank you so much for your help! I used the station robot that you sent me and inputted all the measurements, which seemed to solve the problem. All of the joints are rotating correctly now.

I was wondering, when you mention "homing" the robot, does this mean the arm should be positioned at 90 degrees? I would also love to learn more about the steps you followed to edit my station. I'd like to apply the same approach for other robots as well.

I noticed that there were multiple frames in the setup, but the home frame seemed to stay the same. Could you clarify how you handled the reference frames during this process?

Thanks again for your support, and I look forward to hearing from you!
Best regards,
Estefania Mireles
emireles@moldesfrontera.com

[Olivier]

What I mean by homing is the robot being positioned like in the create mechanism UI image, with joint 3 at 90 degrees.

If you need to home a model in RoboDK, place a reference frame on the joint and place the robot links you want to move inside the new frame, then rotate the frame until the robot is homed.

   

Also be sure to check our documentation on how to create robots and mechanisms :  Create a Mechanism or a Robot - RoboDK Documentation

[emireles_moldesfrontera_com]

Thank you for your answer.

I have looked at the documentation but I’m still having some trouble homing the robot to match the Create Mechanism UI (Joint 3 at 90°), and I wanted to clarify a couple of things.

I haven’t been able to place a reference frame exactly at the center of Joint 3. Did you place it manually, or is there a specific tool you used to snap it to the joint center/axis. I’m also not sure how you aligned the frame’s Z-axis with the joint rotation axis, since Align frame orientation doesn’t seem to respond when I click the joint geometry.

Additionally, in the homed station you sent me, I noticed there are several reference frames. I just wanted to confirm which frames are used specifically for homing versus those used to define the mechanism.

Lastly, to confirm the workflow: should the frame be fully positioned and aligned before re-parenting the downstream links, and is homing done only by rotating the reference frame (without rotating the CAD parts)?

Thank you,
Estefania