1. A model-based control system for controlling a production system, wherein said production system provides jobs and objectives to the model-based control system, said system comprising: a planner operative to provide the production system with a plan, wherein said planner generates the plan using a depth-first target value search, wherein the depth-first target value search is configured to generate the plan with a failure probability most closely approximating a target value; a system model operative to model the behavior of the production system; and, a diagnosis engine operative to estimate failure probabilities for plans and provide diagnostic guidance to the planner.