Adding a spline joint to the joint collection

[MegMll]

Description

In this PR, we introduce the new spline joint to pinocchio. This implementation is based on the paper of Lee et al. available here

It allows to define a number of SE3 frames, that will define the movement and dynamics of the joint. It's very useful for biomechanics, but can be used in other applications.

Here are videos of two examples written by @lpuch

• Knee
  Knee Movement

• Random Spline
  Random Spline

Future

• Introduce the Spline Surface

[github-actions]

👋 Hi,
This is a reminder message to assign an extra build label to this Pull Request if needed.
By default, this PR will be build with minimal build options (URDF support and Python bindings)
The possible extra labels are:

• build_collision (build Pinocchio with coal support)
• build_casadi (build Pinocchio with CasADi support)
• build_autodiff (build Pinocchio with CppAD support)
• build_codegen (build Pinocchio with CppADCodeGen support)
• build_extra (build Pinocchio with extra algorithms)
• build_mpfr (build Pinocchio with Boost.Multiprecision support)
• build_sdf (build Pinocchio with SDF parser)
• build_accelerate (build Pinocchio with APPLE Accelerate framework support)
• build_all (build Pinocchio with ALL the options stated above)

Thanks.
The Pinocchio development team.

[florent-lamiraux]

Please be aware that modifying the joint collection breaks the API.

[jorisv]

@florent-lamiraux We are not considering adding a joint an API break.
If your code rely on JointCollection order or must handle all the joints inside it, please, create your own joint collection.

[Ipuch]

@MegMll and I were talking about this PR. As Megan left WILLOW and she is full time on other projects now, it's hard for her to pursue the debugging that this PR requires, and looking for why the tests were not passing. Does anyone would like to help and/or review this PR?

Here is the focused help, that would be appreciated and could unlock our next developments.

• We don't know why window tests with python doesn't pass ?
• We don't know why it compiles with MacOs Arm, but the test doesn't pass when executed ?

Let us know in which time frame anyone can help, before @MegMll totally loose track of what she had undertaken.

[jorisv]

Hello @Ipuch,

Now we released pinocchio 4, I will probably be able to work again on this PR next month.
I will also check if there is some other engineer in the team able to work on it.

need to rcheck every test and put all the files in the right folder after rebase of pinocchio 4

[MegMll]

Okay i won't be available in May, but if i need to make some changes myself, i guess it can wait June, anyway