THÔNG TIN TÀI LIỆU
' Journal of Science & Technology 101 (2014) 030-034 An Object-Oriented Model to Implement Controllers for Industrial Hybrid Dynamic Systems Hoang Sinh Truong, Ngo Van Hien' Hanoi University of Science and Technology No I Dai Co Viet Str Ha Noi Viet Nam Received- October 25, 2013; accepted: April 22, 2014 Abstract This paper presents a novel object-onented model, which is based on the Real-Time Unified Modeling Language (UML) and Modelica language combined with hybrid automata to effectively analyze, design and implement contnDllers of industnal Hybrid Dynamic Systems (HDS) This model also allows the developed generic artifacts to be customizable and re-usable in the design phase of new HDS confrof applications The paper brings out step-by-step the dynamic analysis model of an industnal HDS specified by hybnd automata, as well as the detailed design model of HDS controllers earned out by specializing Real-Time UlvIL, that permits us to quickly find out the main control capsules, their ports and communication protocols in order to precisely model and tightly allocate control structures corresponding with dynamic behaviors for the implementation model of industrial HDS The detailed design model is then converted into l^odelica models m order to quickly simulate and implement the controller of this HDS Based on this approach, a controller of electro-hydraulic governor for small hydropower stations is completely designed and simulated Keywords, Hybnd Dynamic System, Hybrid Automata, Real-Time UML, Modelica Introduction Control systems of actual machines or actuators take account of models with discrete events and continuous behaviors that are called Hybrid Dynamic Systems (HDS) [1,2], These systems always not have the same behavior because they are associated with validity hypotheses to check at any moment; the security requirement forces to envisage events and behaviors different from nominal behaviors The behaviors of such systems are thus complex, and can he modeler by Hybrid Automata (HA) [1,3] In addition, the immersion in an industrial control context requires the customization and re-utilization are factors to he associated with the production of a new application m order to reduce its costs, resources and time development According to the Object Management Group (OMG) [4], the Real-Tune UML version can be chosen to specify the design model of the developed HDS in detail This version includes the 'capsules, parts, protocols, connectors' concepts that we adapted by specializing a set of capsules in precise behaviors for IndusU-ial HDS (IHDS) Furthermore, Modelica is also the object-oriented modeling language; but it is primarily used to analyze the continuous and discrete time dynamics of complex • Corresponding Author Tel: (+84) 904.255.855 Email hi en ngovan@hust.edu systems based on solving differential and algebraic equaUons [5,6] Starting from the above considered points, we have developed an object-oriented model, which is mainly based on Real-Time UML and Modelica combined with HA in order to effectively analyze, design and implement controllers of IHDS In our model, we adapt the specification of an IHDS modeled with HA, and specialize Real-Time UML's features, e,g capsules, ports, protocols and connectors to completely obtain an object oriented implementation model of HA for the IHDS controller The detailed capsule collaboration is then converted into Modelica models in order to quickly simulate and realize this IHDS controller Finally, this approach is applied to completely design and simulate a controller of Electro-Hydraulic Governor (EHG), which permits the frequency of a small hydropower station to be stabilized Dynamic analysis model for an ihds 2.1 Specification of industrial HDS In general, HDS are those systems with interacting continuous and discrete system dynamics [1,4], A HDS has a continuous evolufion and occasional jumps The jumps conespond to the change of state in an automaton that transits In response to external events or to the continuous evolution A continuous evolution is associated to each stale of the automaton by means of ordinary Journal of Science & Tecbnology 101 (2014) 030-034 differential equations The structure of the equations and the initial condition may be different for each state In this paper, we are interested in analyzmg and designing an IHDS, This IHDS contains two parts, which are the HDS controller and controlled HDS [3,7] These parts mutually exchange periodic signals and episodic events The episodic event is either external or internal Fig, shows out the block diagram of an IHDS must he so thit the transition can be crossed Jump represents the continuous state transformation durmg the change of situition it is generally expressed by a state value fiinction whose result is affected like mitial value of the contmuous state m the new situation tr c ,Z' presents the event being associated to the transition tbis association does not impl> to gne an input or output du'ection to the e\ ent Industrial HDS In\ IS an application which associates a subset of the state space to each situation it is called the mvanant of the situation in which the contmuous state must remain when the situation is q the contmuous state must venty T e im fq) (IHDS) HDS Co „, , E ,, s -y'- -\- • ^ ,< — - > - ' \ ^ ^ k- ^ Fig Block diagram of industrial HDS Where Eo are output events; E, are input events; So are output signals; Si are input signals; AT is a sampling period of the evolufion model; Actori, Actori, , Actorm are descriptions of a coherent set of roles that users (i e persons or involved extemal systems) play when they interact with the developed IHDS, An IHDS and its actors asyn-chronously exchange messages that can be carried out by a state machine The confroUed HDS may evolve along with several models from the mdustrial control perspective; interactions between these models can be presented by using one of formalisms such as HA, Hybrid Grafcet, Hybrid Pefri Nets, etc [1,3] 2.2 Specialization of HA to model dynamic behaviors of an IHDS A hybnd automaton [1,2] is defined by data of F! = (Q, X, Z A, Inv, F, qo, Xa), here' g is a set of states describing operational modes of the system, called situations; ?„ is the initial situation X presents the continuous state space of the automaton, X
Ngày đăng: 08/12/2022, 17:18
Xem thêm: