Hexapod kinematics

[Garth_42]

@JoergS5 ah I see, thanks for clarifying that. I have implemented inverse kinematics in python but I am having more trouble coming up with the forward kinematics. After that I am planning on converting it to C++ and adding it to the repo. Thanks for linking that post, it has a lot of useful info!

[dc42]

I can see that the forward kinematics will be challenging! Six nonlinear equations to solve. The forward kinematics is needed by RRF only occasionally, so it doesn't need to be fast. An iterative solution may be appropriate.

PS a search for "Stewart platform forward kinematics" produces several promising results.

[JoergS5]

@Garth_42
https://github.com/LinuxCNC/linuxcnc/blob/2.7/src/emc/kinematics/genhexkins.c solves forward iterative, analyzing the code could give you some hints.

But you can learn a lot by drawing the kinematics and thinking about how to solve the equations yourself. You can try to solve with trigonometric functions (sin, cos, tan) or by geometric functions (thales, circle intersection) or both, they are connected.

It also helps to read scientific articles, which explain formulae in their introduction sections, before they discuss improvements to a specific topic. Some offer free pdfs.

[Garth_42]

Thanks both for your suggestions! I am slowly making progress. That repo is actually what I am using to develop a solution and am getting close. I am a little confused as to some of the matrix operations but I should be able to replicate it nonetheless.