Design of Digital Control Systems by Nonlinear Uncertain Objects

Author(s):  
Vladimir Elsukov ◽  
◽  
Anatoly Gaiduk ◽  
Vjacheslav Lachin ◽  
Alexandr Muzhenko ◽  
...  

Minimum-phase nonlinear objects in the conditions of incomplete information about state variables and nonlinearities of the objects are considered. The design method of the digital automatic control systems in the conditions of uncertainty is offered. The decision is received with application of the asymptotic observers and control on state and impact under conditions of full controllability and observability of the controlled objects. This control provides the necessary performance of the control systems. The digital devices algorithm of digital control system is received by sampling of the found control. The efficiency of the developed method is shown on the numerical example. The developed method can be applied to design of digital control systems of production and technological objects of various assignment.

Author(s):  
Vladimir Aleksandrovich Konevtsov ◽  
Lilia Motaylenko

Dependencies between signals and dependence of signals on time are strictly non-linear. Non-linear elements, commonly used in the synthesis of automatic control systems, include: a two-point link, a two-point link with hysteresis, a three-point link, a three-point link with hysteresis, a module, saturation with insensitivity.


Author(s):  
Vjacheslav Lachin ◽  
◽  
Anatoly Gaiduk ◽  
Alexandr Muzhenko ◽  
◽  
...  

This article is devoted to development of a method of the digital control systems design with not gaged state variables of the object with uncertain nonlinearity. Application of two observers to find the asymptotic es-timates of the nonlinearity and the state vector of the object is the main feature of the developed approach. The problem of designing is solved on the basis of the discrete-time model of the object with application of the con-trol on output and impacts and the standard normalized transfer functions. It allows to provide the required indicators of quality both in established, and in a transient mode. The numerical example illustrates effectiveness of the developed method. The obtained results can be used to design of digital control systems which can significantly increase effectiveness of the controlled objects as production and special assignment.


AIAA Journal ◽  
1970 ◽  
Vol 8 (4) ◽  
pp. 820-822
Author(s):  
CHARLES L. PHILLIPS ◽  
JOHN C. JOHNSON

Author(s):  
Hui-Wen Huang ◽  
Chunkuan Shih ◽  
Swu Yih ◽  
Yen-Chang Tzeng ◽  
Ming-Huei Chen

A frame-based technique, including physical frame, logical frame, and cognitive frame, was adopted to perform digital I&C failure events derivation and analysis for generic ABWR. The physical frame was structured with a modified PCTran-ABWR plant simulation code, which was extended and enhanced on the feedwater system, recirculation system, and steam line system. The logical model is structured with MATLAB, which was incorporated into PCTran-ABWR to improve the pressure control system, feedwater control system, recirculation control system, and automated power regulation control system. As a result, the software failure of these digital control systems can be properly simulated and analyzed. The cognitive frame was simulated by the operator awareness status in the scenarios. Moreover, via an internal characteristics tuning technique, the modified PCTran-ABWR can precisely reflect the characteristics of the power-core flow. Hence, in addition to the transient plots, the analysis results can then be demonstrated on the power-core flow map. A number of postulated I&C system software failure events were derived to achieve the dynamic analyses. The basis for event derivation includes the published classification for software anomalies, the digital I&C design data for ABWR, chapter 15 accident analysis of generic SAR, and the reported NPP I&C software failure events. The case study of this research includes (1) the software CMF analysis for the major digital control systems; and (2) postulated ABWR digital I&C software failure events derivation from the actual happening of non-ABWR digital I&C software failure events, which were reported to LER of USNRC or IRS of IAEA. These events were analyzed by PCTran-ABWR. Conflicts among plant status, computer status, and human cognitive status are successfully identified. The operator might not easily recognize the abnormal condition, because the computer status seems to progress normally. However, a well trained operator can become aware of the abnormal condition with the inconsistent physical parameters; and then can take early corrective actions to avoid the system hazard. This paper also discusses the advantage of Simulation-based method, which can investigate more in-depth dynamic behavior of digital I&C system than other approaches. Some unanticipated interactions can be observed by this method.


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