kontrolem_example_robots — example URDFs

Example robot URDFs used throughout the framework’s documentation and tests. Currently ships one robot; more example systems can be added under urdf/ and referenced the same way.

cart_double_inverted_pendulum

A cart (prismatic, actuated) carrying two pendulum links (joint1 revolute, actuated; joint2 revolute, passive):

package://kontrolem_example_robots/urdf/cart_double_inverted_pendulum.urdf

Joint	Type	Actuated	Notes
cart_joint	prismatic	yes	horizontal cart position, ±2 m
joint1	revolute	yes	first pendulum link
joint2	revolute	no	second pendulum link (passive)

At q = 0 both links point straight up — the classic unstable upright equilibrium. It was chosen as the running example because it exercises the framework’s interesting paths:

• Underactuated (3 DoF, 2 actuators) yet controllable and observable — actuation selection matters.

• The upright pose needs zero torque on the passive joint by construction, so it linearizes with no equilibrium warning and is a convenient zero-effort seed for the wizard’s automatic equilibrium finder.

• The open loop has two right-half-plane poles — stabilization is a real demo, and the closed-loop response animation actually shows something.

Try it end to end in the Quickstart.