The Observability Concept in a Class of Hybrid Control systems (original) (raw)
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A Class of Hybrid Control Systems – Basic Problems and Trends
Revue Roumaine des Sciences Techniques - Serie Électrotechnique et Énergétique
In the hybrid control systems (HCSs) approach considered in this paper, a continuous system is controlled, through an interface, by a discrete event system (DES), representing the controller. Starting from a partition of the continuous state space into open cells, the continuous systemi.e. the plantcoupled to the interface is first abstracted to a discrete state, event driven model. The DES controller is built then within the DES control theory. This contribution emphasizes some specific problems and difficulties arising in this HCSs approach and proposes some extensions and future research directions. A simple and intuitive "toy" example accompanies the theoretical facts.
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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.
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Mathematical and Computer Modelling
Hybrid control systems, that is, systems which contain both continuous dynamics and discrete event dynamics are studied in this paper. First, a model is introduced that describes the continuous plant and discrete event controller along with an interface which connects them. A Discrete Event System (DES) automaton description is employed to describe the plant together with the interface and it is used to analyze the hybrid control system. Controllability is defined for hybrid control systems, enhancing existing DES control concepts. It is then used to obtaiu a controller design method for hybrid control systems.
Observability for hybrid systems
2003
Abstract The notion of generic final-state asymptotically determinable hybrid system is introduced. Then, sufficient conditions for a linear hybrid system to be generic final-state asymptotically determinable are given. These conditions show that generic final-state asymptotic determinability can be verified even if each of the continuous subsystems of the hybrid system is not observable.
Supervisory control of hybrid systems
Proceedings of The IEEE, 2000
In this paper, the supervisory control of hybrid systems is introduced and discussed at length. Such control systems typically arise in the computer control of continuous processes, for example, in manufacturing and chemical processes, in transportation systems, and in communication networks. A functional architecture of hybrid control systems consisting of a continuous plant, a discrete-event controller, and an interface is used to introduce and describe analysis and synthesis concepts and approaches. Our approach highlights the interaction between the continuous and discrete dynamics, which is the cornerstone of any hybrid system study. Discrete abstractions are used to approximate the continuous plant. Properties of the discrete abstractions to be appropriate representations of the continuous plant are presented, and important concepts such as determinism and controllability are discussed. Supervisory control design methodologies are presented to satisfy control specifications described by formal languages. Several examples are used throughout the paper to illustrate our approach.
1995
In this section we present an overview for the development of complex discrete event and hybrid systems within the robotics, automation, and intelligent system domain. We start by presenting an overview of discrete event and hybrid systems, and then illustrate the concept by an example from the robotics and automation domain. The application discussed is for formulating an observer for manipulating agents. 8.7.1
DES abstractions for the supervisory control of hybrid systems
Transactions of the Institute of Measurement and Control
An examination of the literature results on timed and untimed discrete event system (DES) models reveals clearly that the supervisory control problem is more tractable on untimed models. Thus it is interesting to consider the extent to which untimed DES models can be used to design controllers for dynamical systems. In order to approach a larger class of systems appropriate abstraction methods are necessary as well as some extensions of the untimed supervisory control methods. This paper proposes an abstraction procedure that can be used to extract untimed DES models from hybrid automata models with control inputs and continuous disturbances. The abstractions obtained using this procedure are state machines in which every state corresponds to a region of the state space of the hybrid automaton and transitions between states correspond to transitions between the regions. Results describing properties of the abstraction procedure are obtained, including a semidecidability result. The ...
Interface and controller design for hybrid control systems
Lecture Notes in Computer Science, 1995
The hybrid control systems considered here consist of a continuous-time plant under the control of a discrete event system. Communication between the plant and controller is provided by an interface which can convert signals from the continuous domain of the plant to the discrete, symbolic domain of the controller, and vise-versa. When designing a controller for a hybrid system, the designer may or may not be free to design the interface as well. This paper examines these two cases. First, a methodology is presented for designing a controller when the interface and plant are given. This approach is based on the methodology for controller design in logical discrete event systems. Second, a method is presented to design both the interface and controller. This approach is based on the natural invariants of the system.