Novel Multiscale Control Scheme for Nonminimum-Phase Processes

Abstract. This paper presents a new control strategy which unifies the direct and indirect multi-scale control schemes via a double-loop control structure. This unified control strategy is proposed for controlling a class of highly nonminimum-phase processes having both integrating and unstable modes. This type of systems is often encountered in fed-batch fermentation processes which are very difficult to stabilize via most of the existing well-established control strategies. A systematic design procedure is provided where its applicability is demonstrated via a numerical example.

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“…The details of multi-scale control (MSC) scheme can be found in [14][15][16][17]. A brief overview of the MSC scheme is presented.…”

Section: Multi-scale Control Schemementioning

confidence: 99%

A unified double-loop multi-scale control strategy for NMP integrating-unstable systems

Seer

Nandong

2016

IOP Conf. Ser.: Mater. Sci. Eng.

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“…An interesting feature of the proposed approach is that both the feedback and feedforward controllers are designed based on the recently proposed multi-scale control (MSC) scheme in [10,11]. The authors in [10,11] demonstrated the use of the MSC scheme in designing a PID controller augmented with a filter.…”

Section: Introductionmentioning

confidence: 99%

A unified design for feedback-feedforward control system to improve regulatory control performance

Nandong

2014

Int. J. Control Autom. Syst.

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The PID controller is widely used in industries because of its simplicity and robustness. A simple approach to improve regulatory control performance is to combine both feedback PID and feedforward controllers. The feedforward controller enables early compensation of a measured disturbance before it can seriously affect the process. The conventionally derived non-ideal feedforward controllers are not often used in practice. The reason is that an ideal feedforward controller based on direct inversion of process model is often not physically realizable. Several non-ideal feedforward control designs have been proposed where some of them involve rather intensive tuning procedure to obtain good disturbance rejection. In this paper, we present a new systematic method for designing a combined feedback-feedforward control system. The proposed design method is easy to use and applicable to stable, unstable and integrating deadtime processes where the ideal feedforward controller is physically not realizable.

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“…This new scheme is called the ICD-MSC, and it is based on the MSC scheme recently proposed by Nandong and Zang [24,25] for SISO nonminimum-phase processes. The design principle of the MSC scheme is to first decompose a given plant into a sum of basic modes, each having distinct speed of responses.…”

Section: Introductionmentioning

confidence: 99%

“…Note that the inner feedback loop is faster than the outer feedback loop. Hence, the scheme is called the MSC because of the combination of several sub-controllers with different speeds [24,25].…”

Section: Introductionmentioning

confidence: 99%

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

Nandong

Zang

2014

Chemical Product and Process Modeling

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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.

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Novel Multiscale Control Scheme for Nonminimum-Phase Processes

Cited by 16 publications

References 22 publications

A unified double-loop multi-scale control strategy for NMP integrating-unstable systems

A unified double-loop multi-scale control strategy for NMP integrating-unstable systems

A unified design for feedback-feedforward control system to improve regulatory control performance

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

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