2,029 research outputs found
Process operating mode monitoring : switching online the right controller
This paper presents a structure which deals with
process operating mode monitoring and allows the control law reconfiguration
by switching online the right controller. After a short
review of the advances in switching based control systems during
the last decade, we introduce our approach based on the definition
of operating modes of a plant. The control reconfiguration
strategy is achieved by online selection of an adequate controller,
in a case of active accommodation. The main contribution lies
in settling up the design steps of the multicontroller structure
and its accurate integration in the operating mode detection and
accommodation loop. Simulation results show the effectiveness
of the operating mode detection and accommodation (OMDA)
structure for which the design steps propose a method to study the
asymptotic stability, switching performances improvement, and
the tuning of the multimodel based detector
Approximately bisimilar symbolic models for incrementally stable switched systems
Switched systems constitute an important modeling paradigm faithfully
describing many engineering systems in which software interacts with the
physical world. Despite considerable progress on stability and stabilization of
switched systems, the constant evolution of technology demands that we make
similar progress with respect to different, and perhaps more complex,
objectives. This paper describes one particular approach to address these
different objectives based on the construction of approximately equivalent
(bisimilar) symbolic models for switched systems. The main contribution of this
paper consists in showing that under standard assumptions ensuring incremental
stability of a switched system (i.e. existence of a common Lyapunov function,
or multiple Lyapunov functions with dwell time), it is possible to construct a
finite symbolic model that is approximately bisimilar to the original switched
system with a precision that can be chosen a priori. To support the
computational merits of the proposed approach, we use symbolic models to
synthesize controllers for two examples of switched systems, including the
boost DC-DC converter.Comment: 17 page
Model predictive control techniques for hybrid systems
This paper describes the main issues encountered when applying model predictive control to hybrid processes. Hybrid model predictive control (HMPC) is a research field non-fully developed with many open challenges. The paper describes some of the techniques proposed by the research community to overcome the main problems encountered. Issues related to the stability and the solution of the optimization problem are also discussed. The paper ends by describing the results of a benchmark exercise in which several HMPC schemes were applied to a solar air conditioning plant.Ministerio de Eduación y Ciencia DPI2007-66718-C04-01Ministerio de Eduación y Ciencia DPI2008-0581
PLC Implementation of Supervisory Control for a Dynamic Power Flow Controller using a Modular Approach
Dynamic Power Flow Controller (DPFC) provides steady-state and dynamic power flow control for power lines and is considered as a Flexible AC Transmission System (FACTS) controller. This paper deals with control of a standard DPFC using a Discrete Event System model. The
Supervisory Control of DES has been used to implement Modular supervisors for the DPFC. Despite the fact that the SCT is well consolidated, with a large number of publications focusing on the theoretical aspects, the industrial application is unknown. It is mainly due to the complexity of the theory. The numbers of states and events to be controlled are very large even for the seemingly simple systems. In recent years, a model for modular approach to the Supervisory Control for performing the formal synthesis of Supervisors has been proposed. Programmable Logic Controllers are used for the physical implementation of the controllers. Some problems in physical realization of Supervisors in PLCs are dealt with
Simulation and Bisimulation over Multiple Time Scales in a Behavioral Setting
This paper introduces a new behavioral system model with distinct external
and internal signals possibly evolving on different time scales. This allows to
capture abstraction processes or signal aggregation in the context of control
and verification of large scale systems. For this new system model different
notions of simulation and bisimulation are derived, ensuring that they are,
respectively, preorders and equivalence relations for the system class under
consideration. These relations can capture a wide selection of similarity
notions available in the literature. This paper therefore provides a suitable
framework for their comparisonComment: Submitted to 22nd Mediterranean Conference on Control and Automatio
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