PUMA 200 Robotarm and some Hal/INI issues

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03 Aug 2026 07:59 #348405 by Aciera
Replied by Aciera on topic PUMA 200 Robotarm and some Hal/INI issues
It's going to very difficult to troubleshoot the basic setup by running random gcode files. You need to take a step back and simplify things so you can actually wrap your head around what is going on.

First you need to verify that your home position is really putting the arm in the pose it should be. Which means the pose shown on the drawing you posted earlier. If your flange is not correctly oriented to the base plane (ie parallel or perpendicular to your table) then you need to adjust your HOME, HOME_OFFSET values in the INI.


Once you have verified that the home position is actually correct, you can check your DH parameters by positioning the arm in different simple poses in joint mode, then switch to world mode and check if the cartesian coordinates in the DRO make sense. Simple poses would be those with joint angles like 0°,90°,180°. Make a diagram on paper, calculate the theoretical XYZ position using your robots link lengths and compare that to the XYZ values in the DRO.
Small inaccuracies are to be expected but if you have a rotation direction or a link direction wrong then your values would be way off.

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03 Aug 2026 14:43 #348413 by hitchhiker
Replied by hitchhiker on topic PUMA 200 Robotarm and some Hal/INI issues
You mean this position? 

I was thinking it was only to show dimension?!
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03 Aug 2026 15:33 #348416 by Aciera
Replied by Aciera on topic PUMA 200 Robotarm and some Hal/INI issues
Yes, although I think that your DH parameters have the wrist pointing straight down. Having it point straight down instead of 90° to the right as in the image is not wrong but it is a singular pose and hence you need [JOINT_4] 'HOME = 0.1' in your ini file to avoid an inverse kinematic failure right after homing.

In any case, the important thing is that the home pose MUST be the same pose as what you used to derive your DH parameter values. If an angle in the model is 1.570796 then the angle between the corresponding links of your physical arm needs to be as exactly 90° as possible when all joints are at 0°.
In other words:
With all joints at 0° your upper arm needs to be horizontal and your lower arm needs to be vertical like in the drawing. If you have setup your DH parameters for the pose with the hand pointing straight down then the center of the flange needs to be exactly vertical below the wirst.

That is really why you need to understand what those DH-parameters mean in your particular robot.
The following user(s) said Thank You: tommylight, hitchhiker

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03 Aug 2026 16:57 #348419 by hitchhiker
Replied by hitchhiker on topic PUMA 200 Robotarm and some Hal/INI issues
i got some datasheets... interesting part:


i the joint angle view.... the arm is upside down?!
the arrows and signs show the alpha for each joint?! or i am wrong.. then is my DH parameter list complete wrong...

in the drawing with the measurements... the arm is in the NEST position... dont care.. but all measurements are present... now.. i wonder because:

joint 1 is the base which rotate left and right              alpha 0
joint 2 is the upper arm on the shoulder                     alpha+
joint 3 is the lower arm on the elbow                          alpha+
joint 4 wrist rotate                                                        alpha 0
joint 5 wrist roll                                                            alpha +
joint 6 toolplate rotate                                                 alpha 0


we have a side offset from shoulder rotation point to base rotation point..
we have a side offset from upper arm to lower arm...

but i was thinking that the side offset ist from base turn point to middle upper arm..... complete wrong?!

thanks guys!

 
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