What is the difference between the Jacobian w.r.t kQdot and kv from trajectory optimization perspective as in Jacobian methods in Drake.
In my case, I have defined the contact Jacobians between two floating rigidbodies. And I used CalcJacobianSpatialVelocity to map contact force to generalized forces.
In a system, we have the state as [q v]. I think I understand the kv option, but what is for the kQdot used for. Are there any examples showing the use case with kQdot?
Using kQdot is more akin to a partial derivative; it is often used in optimization (e.g. to know how to change q to improve some objective). For instance, you'll find lot of uses in the drake/multibody/inverse_kinematics folder.
I have some notes about this topic here, including some discussion on qdot vs v.