I actually talked to someone in industrial robotics, and message passing / message buses are really common there. All of their controllers are loosely coupled,

I actually talked to someone in industrial robotics, and message passing / message buses are really common there. All of their controllers are loosely coupled, because each unit might be from a different vendor, upgraded at a different time, etc... It also had the nice property that their systems all had multiple supervisors, and if the supervisor detected a bad state by monitoring the bus passively, it could stop all of controllers.