Model-checking real-time control programs: verifying Lego(R) MindstormsTM systems using UPPAAL

In this paper, we present a method for automatic verification of real-time control programs running on LEGO RCX bricks using the verification tool UPPAAL. The control programs, consisting of a number of tasks running concurrently, are automatically translated into the timed automata model of UPPAAL. The fixed scheduling algorithm used by the LEGO RCX processor is modeled in UPPAAL, and supply of similar (sufficient) timed automata models for the environment allows analysis of the overall real-time system using the tools of UPPAAL. To illustrate our techniques we have constructed, modeled and verified a machine for sorting LEGO bricks by color.