scholarly journals Generalized multi-scale control scheme for cascade processes with time-delays

2014 ◽  
Vol 24 (7) ◽  
pp. 1057-1067 ◽  
Author(s):  
Jobrun Nandong ◽  
Zhuquan Zang
Keyword(s):  
Time Delays ◽  
Multi Scale ◽  
Control Scheme ◽  
Cascade Processes ◽  
Scale Control

scholarly journals Inter-Communicative Decentralized Multi-Scale Control (ICD-MSC) Scheme: A New Approach to Overcome MIMO Process Interactions

2014 ◽  
Vol 9 (2) ◽  
pp. 165-178 ◽  
Author(s):  
Jobrun Nandong ◽  
Zhuquan Zang
Keyword(s):  
Decentralized Control ◽  
Pid Control ◽  
Detrimental Effect ◽  
Numerical Study ◽  
Control Performance ◽  
Alternative Scheme ◽  
Multi Scale ◽  
Control Scheme ◽  
Communicative Structure ◽  
Scale Control

Abstract Decentralized PID control has been extensively used in process industry due to its functional simplicity. But designing an effective decentralized PID control system is very challenging because of process interactions and dead times, which often impose limitations on control performance. In practice, to alleviate the detrimental effect of process interactions on control performance, decoupling controllers are often incorporated into a decentralized control scheme. In many cases, these conventional decoupling controllers are not physically realizable or too complex for practical implementation. In this paper, we propose an alternative scheme to overcome the performance limitation imposed by process interactions. This new control scheme is extended from the SISO multi-scale control scheme previously developed for nonminimum-phase processes. The salient feature of the new control scheme lies in its communicative structure enabling collaborative communication among all the sub-controllers in the system. This communicative structure serves the purpose of reducing the detrimental effect of process interactions leading to improved control performance and performance robustness. Extensive numerical study shows that the new control scheme is able to outperform some existing decentralized control schemes augmented with traditional decoupling controllers.

Decentralized Control Design for Ethanol Fermentation by Zymomonas Mobilis – Multi-Scale Control Approach

2014 ◽  
Vol 625 ◽  
pp. 34-37
Author(s):  
Qiu Han Seer ◽  
Jobrun Nandong ◽  
Zhu Quan Zang
Keyword(s):  
Decentralized Control ◽  
Ethanol Fermentation ◽  
Zymomonas Mobilis ◽  
Ethanol Yield ◽  
Control Design ◽  
Product Inhibition ◽  
Control Approach ◽  
Multi Scale ◽  
Control Scheme ◽  
Scale Control

This paper deals with the decentralized control design for ethanol fermentation by Zymomonas mobilis. Extractive fermentation has been proposed to improve the ethanol yield and productivity due to product inhibition. The complexity of biological systems and significant process variability can always lead to ineffective control system performance. In this paper, a 2x2 and 3x3 multi-scale control systems have been proposed. It is shown that the PID control design based on the multi-scale control scheme is effective for complex high-order systems.

Control of Two-Link Flexible Structures

Volume 1 ◽  
2004 ◽  
Author(s):  
Clarice Wagner-Nachshoni ◽  
Yoram Halevi
Keyword(s):  
Transfer Function ◽  
Time Delays ◽  
Wave Motion ◽  
Controller Design ◽  
Flexible Structures ◽  
Infinite Dimensional ◽  
Second Stage ◽  
Finite Dimensional ◽  
Control Scheme ◽  
Two Stages

A method of noncollocated controller design for non-uniform flexible structures, governed by the wave equation, is proposed. An exact, infinite dimensional, transfer function, relating the actuation and measurement points, with general boundary conditions, is derived for the multi-link case. Three modeling methods are presented and discussed. A key element of the model is the existence of time delays, due to the wave motion, which play a major role in the controller design. The design consists of two stages. First an inner rate loop is closed in order to improve the system dynamic behavior. It leads to a finite dimensional plus delay inner closed loop, which is the equivalent plant for the outer loop. In the second stage an outer noncollocated position loop is closed. It has the structure of an observer–predictor control scheme to compensate for the response delay. The resulting overall transfer function is second order, with arbitrarily assigned dynamics, plus delay.

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