An Accessibility Analysis Method for Hybrid Systems

Abstract

The invention provides a reachability analysis method of a hybrid system. The reachability analysis method comprises the following steps that input files of a hybrid automaton are analyzed, and the bounded figure structure of the automaton is encoded into a propositional logic formula set; an SAT solver is used for solving the formula set, if the formula set can not be solved, an output result is insoluble, and if the output result is soluble, an assignment capable of being met is decoded to be a path on the figure structure of the automaton; a target path is encoded to form linear constraint according to the meaning of the hybrid automaton; the linear constraint is solved, if the linear constraint is soluble, the path is output as a result, and if the linear constraint is insoluble, a next step is turned; an irreducible and insoluble set of the linear constraint is given; an unreachable path is encoded into the propositional logic formula set and then is added into the formula set of the figure structure of the automaton. The reachability analysis method is used so that the candidate path for reaching a target node can be quickly found out, and the time for searching the figure structure of the hybrid automaton can be shortened.

Description

Technical field [0001] The invention relates to the field of accessibility analysis of a hybrid system, in particular to a method for accessibility analysis of a hybrid system guided by SAT, LP, and IIS (irreducible and insoluble set) dynamic feedback. [0002] The satisfiability of propositional logic SAT (booleansatisfiability) is to determine whether there is an assignment that makes the set of given propositional logic formulas true. Linear programming LP (linear programming) is to determine whether there is a solution that satisfies a given set of linear inequalities. Irreducible insolvable set IIS (irreducible infeasible set) refers to a subset of a set of unsatisfiable linear constraints. Its characteristic is that the set is not solvable, but the set can be solved by removing any one of the constraints. Background technique [0003] Hybrid system is a kind of complex system with both discrete and continuous behavior characteristics. In real life, especially in aerospace, ...

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Problems solved by technology

However, since this method needs to encode all the behaviors of the system in k steps into a constraint set before testing, when the scale of the problem, such as the size of the given step size, the number of system variables, the number of members in the automaton combination, etc., increases, the size of the constraint set will grow rapidly, leading to a corresponding sharp increase in memory requirements, which in turn limits the size of the problem that can be solved

In addition, although the accessibility problem of linear hybrid systems can be solved by using SMT, the general satisfiability method, in a certain coding method, the coding itself is a very complicated task, and there is currently no corresponding supporting tool to solve it. finish this job

For design and modeling engineers of hybrid systems, converting the corresponding linear hybrid automaton model into an SMT problem would be a very difficult and error-prone task without relevant long-term training

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