# Calculation of configuration (CF1, CF4, CF6) given CFX

Hi all,

So, I've created an HMI application for an IRB120 so that the user can input a target in the shape:
• X,Y,Z
• Ez,Ey,EX
• arm (left/right)
• elbow (up/down)
• wrist (flip/no flip)
Given this information I can create a robtarget, except for the configuration. I can calculate "cfx" and leave cf1,cf4 and cf6 with "0" and CalcJoinT will work sometimes, but others it will not calculate the rest of the parameters.

I've tried the brute force method of, given a pose, calculating all possible cf1,cf4 and cf6 combinations, create a jointtarget with them (calcjointt), and then, using calcrobt to see what configuration the robot is really in, but it will not calculate cfx.

My questions are:
• Is there a way of selecting a configuration given a pose (position+orientation)?
• Isn't cfx redundant to  CF1,CF4,CF6?
• Is there a way of calculating CFX ?
• Shouldn't "CalcRobT" calculate cfx as well as cf1,cf4 and cf6?
Best regards

Rodrigo

Finally I had to resort to creating a function that calculates the inverse kinematics of the IRB120 from an initial Pose (Position and orientation) and a given Cx. It seems the way that CalcJointT does not work as I was expecting or I do not understand how the logic has been implemented.

• ✭✭✭
Is it important to you the exact way in which the robot goes to the position or just that it gets there?  If it is the latter, turning Conl\Off and ConfJ\Off will get you there.
Lee Justice
• edited July 2022
lemster68 said:
Is it important to you the exact way in which the robot goes to the position or just that it gets there?  If it is the latter, turning Conl\Off and ConfJ\Off will get you there.
Hi, I need the robot to get there in the cfx I specify. Will I get anywhere with Conl and confJ both to off without specifying cf1 cf4 and cf6 ( or set to zero)?
• ✭✭✭
With either one off it will arrive to the position with the configuration nearest to what it was at the start of the motion.
Lee Justice
• lemster68 said:
With either one off it will arrive to the position with the configuration nearest to what it was at the start of the motion.
Thanks for that Lee but unfortunately that is not what i'm looking for.

I need the robot to go to the pose and configuration I'm setting with Cfx regardless the initial position.