VERIFICATION OF EMBEDDED SUPERVISORY CONTROLLERS CONSIDERING HYBRID PLANT DYNAMICS

Author(s):  
SEBASTIAN ENGELL ◽  
SVEN LOHMANN ◽  
OLAF STURSBERG

This contribution proposes a link between the specification of supervisory controllers by Sequential Function Charts (SFC) and the verification of embedded systems with hybrid dynamics. The SFC are transformed into modular timed automata using a procedure based on graph grammars. The resulting controller model is composed with a hybrid automaton (with possibly nonlinear continuous dynamics) that models the plant behavior. In order to verify safety properties of the composed system algorithmically, a tool implementing the recently proposed approach of counterexample guided model checking is employed. The procedure is illustrated for a processing system example.

Author(s):  
Guillermo Rodriguez-Navas ◽  
Julian Proenza ◽  
Hans Hansson ◽  
Paul Pettersson

Model checking is a widely used technique for the formal verification of computer systems. However, the suitability of model checking strongly depends on the capacity of the system designer to specify a model that captures the real behaviour of the system under verification. For the case of real-time systems, this means being able to realistically specify not only the functional aspects, but also the temporal behaviour of the system. This chapter is dedicated to modeling clocks in distributed embedded systems using the timed automata formalism. The different types of computer clocks that may be used in a distributed embedded system and their effects on the temporal behaviour of the system are introduced, together with a systematic presentation of how the behaviour of each kind of clock can be modeled. The modeling is particularized for the UPPAAL model checker, although it can be easily adapted to other model checkers based on the theory of timed automata.


2021 ◽  
Vol 20 (5s) ◽  
pp. 1-26
Author(s):  
Jinghao Sun ◽  
Nan Guan ◽  
Rongxiao Shi ◽  
Guozhen Tan ◽  
Wang Yi

Research on modeling and analysis of real-time computing systems has been done in two areas, model checking and real-time scheduling theory. In model checking, an expressive modeling formalism such as timed automata (TA) is used to model complex systems, but the analysis is typically very expensive due to state-space explosion. In real-time scheduling theory, the analysis techniques are highly efficient, but the models are often restrictive. In this paper, we aim to exploit the possibility of applying efficient analysis techniques rooted in real-time scheduling theory to analysis of real-time task systems modeled by timed automata with tasks (TAT). More specifically, we develop efficient techniques to analyze the feasibility of TAT-based task models (i.e., whether all tasks can meet their deadlines on single-processor) using demand bound functions (DBF), a widely used workload abstraction in real-time scheduling theory. Our proposed analysis method has a pseudo-polynomial time complexity if the number of clocks used to model each task is bounded by a constant, which is much lower than the exponential complexity of the traditional model-checking based analysis approach (also assuming the number of clocks is bounded by a constant). We apply dynamic programming techniques to implement the DBF-based analysis framework, and propose state space pruning techniques to accelerate the analysis process. Experimental results show that our DBF-based method can analyze a TAT system with 50 tasks within a few minutes, which significantly outperforms the state-of-the-art TAT-based schedulability analysis tool TIMES.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maike Schwammberger

Abstract As automated driving techniques are increasingly capturing the market, it is particularly important to consider vital functional properties of these systems. We present an overview of an approach that uses an abstract model to logically reason about properties of autonomous manoeuvres at intersections in urban traffic. The approach introduces automotive-controlling timed automata crossing controllers that use the traffic logic UMLSL (Urban Multi-lane Spatial Logic) to reason about traffic situations. Safety in the context of collision freedom is mathematically proven. Liveness (something good finally happens) and fairness (no queue-jumping) are examined and verified using a model-checking tool for timed automata, UPPAAL.


Author(s):  
Diego Marmsoler

AbstractCollaborative embedded systems form groups in which individual systems collaborate to achieve an overall goal. To this end, new systems may join a group and participating systems can leave the group. Classical techniques for the formal modeling and analysis of distributed systems, however, are mainly based on a static notion of systems and thus are often not well suited for the modeling and analysis of collaborative embedded systems. In this chapter, we propose an alternative approach that allows for the verification of dynamically evolving systems and we demonstrate it in terms of a running example: a simple version of an adaptable and flexible factory.


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