Simple Inverse Kinematics breaks under Inverse solver

[research_germany]

The following basic set up: three boxes and two revolute joins breaks under the inverse kinematics pseudo inverse calculation method. Even if the target object is restricted to within reachable areas and the XZ plane (where the robot lives). What causes this behavior? Is this a restriction of inverse kinematics inverse method? Just too few degrees of freedom? The DLS method works fine in this situation. Image and file below.

https://www.dropbox.com/s/q1q2vflci55bazj/Capture.PNG

https://www.dropbox.com/s/p5vp1ga4g8936 ... 6.ttt?dl=0

[coppelia]

Hello,

the reason is because you have a 2 DoF manipulator, and specified 3 constraints (x, y and z) for the corresponding IK element. Your system is overconstrained. Simply remove the z constraint (you have defined your IK element relative to the base object of your manipulator, and so your constraints are relative to that object's reference frame).

Cheers

[research_germany]

Thanks for the clarification. Issue solved.

For others if in similar situation please pay attention to this Simply remove the z constraint (you have defined your IK element relative to the base object of your manipulator, and so your constraints are relative to that object's reference frame). Naively one would try to disable the constrain in the global Z coordinate.

Regards