Combined On-Line and Run-to-Run Optimization of Batch Processes with Terminal Constraints

Abstract

This paper describes the optimization of batch processes in the presence of uncertainty and constraints. The optimal solution consists of keeping certain path and terminal constraints active and driving the sensitivities to zero. The case where the terminal constraints have a larger bearing on the cost than the sensitivities is considered, for which a two-time-scale methodology is proposed. The problem of meeting the active terminal constraints is addressed on-line using trajectory tracking, whilst pushing the sensitivities to zero is implemented on a run-to-run basis. The paper also discusses the run-to-run improvement of trajectory tracking via iterative learning control. The proposed methodology is illustrated in simulation on a batch distillation system.

Advanced Control of the Wood Thermal Treatment Processing

“…The strong results of investigations received in the chemical industry about the control of "batch-to-batch" ("run-to-run") processes [3,28] could be a solid base for the incorporation of color measurement at the end of each run;…”

“…Run-to-Run (RtoR) optimization is a well-established method in a case of repetitive (batch) processes in chemical and bio-chemical industries [3,28]. In this work the model based on RtoR optimization is accepted because of availability of proved mathematical models [9,13,15].…”

“…In this paper the functional possibilities of the earlier proposed control system for TTP [13,14,15] are enhanced with emphasis both on the plasticizing and ennoblement (colouring) of the wood via incorporating a new set of Building Blocks (BB) into the control scheme: direct colour measurement at the end of each run [12,21], adaptation of tuning parameters of the accepted model based inference control scheme [18,19], Run-to-Run (RtoR) optimization and re-parameterization [3,28], operational knowledge inclusion in the form of Case-Based Reasoning (CBR) [4,6,16,17,27]. …”

Modelling and control of combined cooling and antisolvent crystallization processes

“…The main disadvantage of the approach is that the operating curve chosen in the phase diagram is not necessarily optimal. Although the close-to-optimal setpoint profile mostly provides very good performance for practical purposes, it is also possible to apply measurement-based optimization approaches (Welz et al, 2004) to improve the initial setpoint profile according to a run-to-run control scheme, leading to an optimal direct design strategy.…”

Iterative Learning Control with Input Shift

“…In the following, the use of an additional time shift of the feedforward input in order to increase robustness will be investigated. This idea was first used in (Welz et al, 2004), with the same shift for the error and the input. The goal of this paper is to extend this idea and use different shifts for the error and the input.…”