Articulating/Multi-Axle Vehicle Control

Here’s the first of what could become many questions, so it’s very broad. Has anyone tried using a Pixhawk for articulating or multi-axle steering vehicle control? I can create a circuit board to adapt a multi-axle steering vehicle using the Ackermann algorithm, but it isn’t obvious to me right now how to control an articulating vehicle since the feedback to the Pixhawk will probably reflect incorrect or high rotation speeds or directions. Also, what are your favorite air and ground simulators that support hardware in the loop?