CODEWITHSUNDEEP
drake
Xiao
Xiao

Reputation: 45

The difference between kQdot and kV when computing the Jacobians

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?

Upvotes: 1

Views: 44

Answers (1)

Russ Tedrake
Russ Tedrake

Reputation: 5533

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.

Upvotes: 1

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