Hybrid Systems: Review and Recent Progress (original) (raw)
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An introduction to hybrid system modeling, analysis, and control
1999
Hybrid systems combine discrete event and continuous time dynamics and can serve as models of large scale systems. We p r o vide an overview of modeling, analysis, and controller synthesis techniques for hybrid systems. A modeling language for describing a wide class of hybrid phenomena is rst presented, and conditions for existence and uniqueness of executions are provided. We then discuss analysis problems, and characterize a class of hybrid systems for which reachability questions can be veri ed automatically. Finally, we review a method for designing controllers for hybrid systems with reachability speci cations.
Modeling and verification of hybrid dynamic systems using multisingular hybrid Petri nets
Theoretical Computer Science, 2012
The aim of this research has been to associate the modeling capacities of hybrid Petri nets with the analysis power of hybrid automata in order to perform formal verification of hybrid dynamic systems. In this paper, we propose an extension of hybrid Petri nets, called multisingular hybrid Petri nets (MSHPNs), for modeling and verification of hybrid dynamic systems. This extension consists of enriching hybrid Petri nets with the capabilities of hybrid automata to control the execution and firing of transitions and some modeling facilities for describing some repeatedly encountered aspects of timed and hybrid systems. We discuss the challenging issues of speed computation raised by addition of execution predicates and introduce a speed-based partitioning technique, which is essential for state space computation. We also introduce a method for reachability analysis of MSHPNs, consisting of computing the state class graph. Thus, the verification of timing properties of MSHPNs can be conducted using the existing techniques and tools. The proposed formalism has the expressiveness of multisingular hybrid automata besides the capabilities of Petri nets for modeling concurrent and distributed systems. Some illustrative examples of the proposed formalism are also presented in this paper.
The Impact of Hybrid Automata on System Modeling and Analysis
The use of formal methods, techniques and tools may generally guarantee a systems' safe operation. Such a process includes system modeling with a mathematical model, which is an approximation of the physical system, and is used to make easier the next step of analysis. Formal analysis of hybrid systems, which involve mixed continuous-valued and discrete dynamics, is concerned with verifying whether a hybrid system satisfies a desired specification, like avoiding an unsafe region of the state space. In this paper, we examine the general impact of hybrid automata on modeling and analyzing hybrid systems and we discuss in particular some advantages that arise when exploiting them in the context of particular methods for verifying the reachability of states in common paradigms that have already being investigated with other classical methods. Finally, we use two case studies concerning different classes of hybrid automata to demonstrate the applicability and the efficiency of explo...
Timed Petri nets in hybrid systems: Stability and supervisory control
1998
In this paper, timed Petri nets are used to model and control hybrid systems. Petri nets are used instead of finite automata primarily because of the advantages they offer in dealing with concurrency and complexity issues. A brief overview of existing results on hybrid systems that are based on Petri nets is first presented. A class of timed Petri nets named programmable timed Petri nets (PTPN) is then used to model hybrid systems. Using the PTPN, the stability and supervisory control of hybrid systems are addressed and efficient algorithms are introduced. In particular, we present sufficient conditions for the uniform ultimate boundness of hybrid systems composed of multiple linear time invariant plants which are switched between using a logical rule described by a Petri net. This paper also examines the supervisory control of a hybrid system in which the continuous state is transfered to a region of the state space in a way that respects safety specifications on the plant's discrete and continuous dynamics.
A mathematical approach to discrete-event dynamic modelling of hybrid systems
Computers & Chemical Engineering, 1996
Presently, design of supervisory control systems is based on ad hoc design methods. This project attempts to approach the design of supervisory controllers using the structure of continuous and sampled systems. The approach builds on process models, incorporates performance specifications and constraints imposed by the plant and otherwise and synthesises the controller by partial inversion of the process model. This paper describes a modelling technology derived for hybrid systems. The hybrid system consists of a continuous plant forced by commands from the supervisory control system and observed through event detectors. The event detectors generate the "measurements" used as inputs to the supervisory control system. The modelling technology quantises the state space systematically and leads to discrete-event dynamic process models that depend on the discrete inputs and the effects of the environments of the plant. Modelling and control of a simple plant is discussed..The resulting controlled systems are analysed for undesirable effects.
Programmable timed Petri nets in the analysis and design of hybrid control systems
Conference on Decision and Control, 1998
In this paper, a class of timed Petri nets, named programmable timed Petri nets is used to model and study switched hybrid systems. Supervisory control of a hybrid system in which the continuous state is transferred to a region of the state space in a way that respects safety specifications on the plant's discrete and continuous dynamics is examined. The
Combining a computer science and control theory approach to the verification of hybrid systems
Proceedings of 5th International Workshop on Parallel and Distributed Real-Time Systems and 3rd Workshop on Object-Oriented Real-Time Systems, 1997
We report on the project "Specification and Verification of Discrete Controllers for Continuous Systems Based on Modular Models and Compositional Analysis". Within this project we aim at developing an automatic verification tool for discrete controllers of technical systems which can be applied to systems of industrial size. To reach this objective we combine two different approaches being used in control theory and computer science. These are the "Timed Condition/Event Systems" (TCESs) and the "Timed Automata" (TAs) formalisms. The state of the project is such that, because of the equivalence of TCESs and TAs we have shown in , it is possible to automatically analyze real-time systems modeled by TCESs with analysis tools developed for TAs. In this paper we describe in detail motivation, goal and state of our project, and illustrate the equivalence of TCESs and TAs.
Overview 1. Hybrid systems-Definition, examples & challenges 2. Hybrid system models-Overview & issues 3. Models for event-driven systems-Automata 4. Hybrid automata 5. PWA systems and related model classes (MLD, LC, MMPS) 6. Timed automata 7.
Proceedings of the IEEE, 2000
Hybrid systems are heterogenous dynamical systems characterized by interacting continuous and discrete dynamics. Such mathematical models have proved fruitful in a great diversity of engineering applications, including air-traffic control, automated manufacturing, and chemical process control. The high-profile and safety-critical nature of the application areas has fostered a large and growing body of work on formal methods for hybrid systems: mathematical logics, computational models and methods, and computer-aided reasoning tools supporting the formal specification and verification of performance requirements for hybrid systems, and the design and synthesis of control programs for hybrid systems that are provably correct with respect to formal specifications. This paper offers a synthetic overview of, and original contributions to, the use of logics and formal methods in the analysis of hybrid systems.