simtk.org

Hi,

I have a question regarding inverse kinematics. I know and have been using the C++ API for performing traditional inverse kinematics using markers placed on (almost) all segments. But now I would like to try to solve a motion where only the end-effectors segment (hands, feet and head) are known. This process or end-effector inverse kinematics is commonly used in robotics for example.
Is there any solver that can perform end-effector inverse kinematics in the C++ API. If yes, can you provide example or ressources?

Thank you

Vincent

Hi Vincent,

Do you mean that you want to specify the end effector position and orientation and perform the inverse kinematics? This is possible with OpenSim/Simbody to track only specific goals (e.g., foot, head, etc.). Also, there is a PR that tried to expose tracking of marker positions and orientation in real-time.

https://github.com/opensim-org/opensim- ... 2855/files

Also you can check the OpenSense tutorial for orientation tracking:

https://simtk-confluence.stanford.edu/d ... h+IMU+Data

Hi Dimitar,

Thank you for your reply.
We looked at the PR and are waiting to be completed (if it happens)

You are right about end-effector IK.
We want to "specify the end effector position and orientation and perform the inverse kinematics".
We are doing it already by using a workaround where we create markers from our IMUs/Rigid bodies data and use the InverseKinematicsSolver to solve the motion and get our coordinate values.
We get a solution but not a pleasing one. The arm adduction/abuction is not natural and we do not know how to solve that.
This is why I asked for the existence of another type of solver.
This is why I also created another post where I was asking if we could add some weights to the coordinate so that the use of the arm adduction/abduction coordinate is down-prioritised when solving the motion: see viewtopicPhpbb.php?f=91&t=12419&p=0&sta ... ac4d941ad2

Thanks anyway

Vincent