RNEA derivatives w.r.t q with external forces fixed in LOCAL_WORLD_ALIGNED frame

[Zionshang]

Hi all,

I am using pinocchio::computeRNEADerivatives to compute the partial derivatives of the inverse dynamics.

My problem involves external forces (e.g., contact forces) that are defined and constant in the LOCAL_WORLD_ALIGNED frame.

computeRNEADerivatives expects f_ext expressed in the LOCAL frame of the joints. If I simply transform my forces to the LOCAL frame and pass them to the function, it computes the derivatives assuming these local force vectors are constant with respect to the link orientation.

However, since my forces are constant in the LOCAL_WORLD_ALIGNED frame, their representation in the LOCAL frame changes with configuration $q$. This implies a missing derivative term related to the rotation of the frame.

My Question:
Is there a recommended way or a specific API in Pinocchio to compute the analytical derivative of the term:

$$\frac{\partial (J(q)^T f_{lwa})}{\partial q}$$

where $f_{lwa}$ is constant?

I noticed getJointKinematicHessian exists, but is there an equivalent like getFrameKinematicHessian or a utility that handles the tensor product with a spatial force directly for operational frames?

Thanks!