A hybrid 2D fault-tolerant controller design for multi-phase batch processes with time delay

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Focusing on industrial processes under uncertainties and partial actuator faults, a new robust constrained model predictive control (MPC) strategy is developed. To enhance the corresponding control performance, a new state-space model in which an extended state vector is constructed by combining the state variables and the tracking error is introduced for the proposed MPC algorithm. As a consequence, there are extra degrees of freedom for the subsequent controller design by adjusting the output tracking error and the state variables separately, and the enhanced control performance is anticipated. Note that the state variables cannot be tuned in the robust MPC design that utilizes the traditional state space model so that its control performance may be limited because of the restricted degrees of freedom. Finally, the validity of the proposed robust MPC strategy is evaluated on the injection velocity control under uncertainties and partial actuator failures.INDEX TERMS Industrial process, partial actuator fault, robust MPC, extended state space model. I. INTRODUCTIONAs a vital role in manufacturing various high-value products, industrial chemical processes exist widely in industries. In order to meet the increasing demands, both the control theory and applications of such processes have gained lots of progresses in the past decades [1], [2]. It is known that the system performance may be deteriorated greatly under all kinds of disadvantages in practice, such as model/plant mismatches, disturbances, actuator faults, etc [3]. Moreover, the existing approaches may hardly satisfy higher control demands [4]. Based on such backgrounds, it is of necessity to research improved control approaches for industrial processes further.Actuators are the essential part in control systems, and they implement the control signals calculated by controllers and ensure the normal operation of industrial processes [5]. However, actuator failures are common in industrial processes, which are caused by some physical damages. Under such situations, the system performance will be affected significantly because the controller output cannot be implemented accurately by the actuator [6]. Generally speaking, there are three common actuator failures, that is, actuator outage, actuatorThe associate editor coordinating the review of this manuscript and approving it for publication was Ruqiang Yan.

Section: Proposed Robust Mpc a Extended State Space Modelmentioning

confidence: 99%

mentioning

confidence: 99%

Improved Robust Constrained Model Predictive Control Design for Industrial Processes Under Partial Actuator Faults

Wang

2019

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“…Multi-phase batch process control has become a hot topic in research [29], [33]- [36]. In [34], a switching system model was used to study a multi-phase batch production process, and a related predictive control strategy was proposed.…”

Section: Introductionmentioning

confidence: 99%

Improved H-Infinity Hybrid Model Predictive Fault-Tolerant Control for Time-Delayed Batch Processes Against Disturbances

Chen

2020

An H-infinity model predictive fault-tolerant control strategy is proposed for multi-phase batch processes with interval delay and actuator failures. First, state variables, state errors and output tracking errors are introduced to establish an extended-state-space switched system model. Then, based on this model, a predictive fault-tolerant control law is designed for tracking the set point by the output that satisfies the requirements of the optimal performance index under input and output constraints. The feasibility conditions for the solvability of the control law are presented in the form of linear matrix inequalities. In addition, the designed switching law is constructed, and the gain of the control law is obtained via the optimization algorithm. This design has several advantages: the output tracking is faster, the tracking performance is superior, and the trace is smoother at the switching time. Finally, through a comparison with traditional methods, the effectiveness and feasibility of this method are demonstrated via injection molding simulation. INDEX TERMS Batch production systems, added delay, fault tolerant control, linear matrix inequalities, Lyapunov methods, predictive models, switching systems, predictive control.

“…However, the above method research on predictive control does not consider the multi-phase characteristics of the batch process, so it cannot guarantee that the system performance is always optimal under the actuator fault, because the control performance of the previous phase will affect the next phase, thereby affecting the product quality. Compared with singlephase control studies, the results of multi-phase processes are relatively small [36]- [38], especially in the case of system faults [39]- [41]. Further analysis of multi-phase batch processes obviously remains to be explored.…”

Section: Introductionmentioning

confidence: 99%

Linear Quadratic Predictive Fault-Tolerant Control for Multi-Phase Batch Processes

Wang

Luo

2019

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This paper proposes a linear quadratic predictive fault-tolerant control (LQPFTC) scheme for multi-phase batch processes with input time-delay and actuator faults. First of all, according to a given model with input time-delay, a new variable is introduced and the given model is transformed into an extended state-space model without time delay. And then, a new 2D switched system model based on an equivalent 2D-Roesser model is constructed by introducing the state error and the output tracking error to solve the actuator fault and realize the optimal control performance. By adjusting the variable in the function, a quadratic performance function based on the model is designed and a linear predictive fault-tolerant controller by combining with the principle of predictive control is proposed. Then, using the Lyapunov function and the average dwell time method, the sufficient conditions for the robust exponential stability of the system along the time and batch direction, and the minimum running time of each phase are derived. Finally, taking the injection molding process as an example, different fault values are selected for simulation. The results show that the 2D controller designed can realize tracking control with different actuator fault values and even a serious one.INDEX TERMS Model predictive fault-tolerant control, batch process, input time-delay, equivalent 2D-Roesser model, actuator faults.