Class Of Linear Hybrid Automata Research Articles

Automatic synthesis of switching controllers for linear hybrid systems: Safety control

In this paper we study the problem of automatically generating switching controllers for the class of Linear Hybrid Automata, with respect to safety objectives. While the same problem has been already considered in the literature, no sound and complete solution has been provided so far. We identify and solve inaccuracies contained in previous characterizations of the problem, providing a sound and complete symbolic fixpoint procedure to compute the set of states from which a controller can keep the system in a given set of desired states. While the overall procedure may not terminate, we prove the termination of each iteration, thus paving the way to an effective implementation.The techniques needed to effectively and efficiently implement the proposed solution procedure, based on polyhedral abstractions of the state space, are thoroughly illustrated and discussed. Finally, some supporting and promising experimental results, based on the implementation of the proposed techniques on top of the tool PHAVer, are presented.

PTIME Parametric Verification of Safety Properties for Reasonable Linear Hybrid Automata

This paper identifies an industrially relevant class of linear hybrid automata (LHA) called reasonable LHA for which parametric verification of convex safety properties with exhaustive entry states can be verified in polynomial time and time-bounded reachability can be decided in nondeterministic polynomial time for non-parametric verification and in exponential time for parametric verification. Properties with exhaustive entry states are restricted to runs originating in a (specified) inner envelope of some mode-invariant. Deciding whether an LHA is reasonable is shown to be decidable in polynomial time.

Positive loop-closed automata: a decidable class of hybrid systems

The model-checking problem for real-time and hybrid systems is very difficult, even for a well-formed class of hybrid systems—the class of linear hybrid automata—the problem is still undecidable in general. So an important question for the analysis and design of real-time and hybrid systems is the identification of subclasses of such systems and corresponding restricted classes of analysis problems that can be settled algorithmically. In this paper, we show that for a class of linear hybrid automata called positive loop-closed automata, the satisfaction problem for linear duration properties can be solved by linear programming. We extend the traditional regular expressions with duration constraints and use them as a language to describe the behaviour of this class of linear hybrid automata. The extended notation is called duration-constrained regular expressions. Based on this formalism, we show that the model-checking problem can be reduced formally to linear programs.