On the Optimal Control of Contact-Cooking Processes

Abstract

SUMMARYIn this study, we have considered the design of optimised thermal processes for the preparation of cooked hamburger patties. For this purpose, advanced dynamic optimisation (optimal control) techniques have been used. These techniques make use of predictive mathematical models of heat and mass transfer, previously validated with experimental studies. The generic optimal control problem considered was formulated as the determination of the optimal cooking conditions to obtain the highest quality product with an ensured final level of safety in a minimum time. The obtained optimal policies (dynamic heating temperatures) show significant advantages over nominal constant temperature processes. These optimisation studies provide new information to design the next generation of grills with dynamic controls to improve the product quality and safety

Predictive control with multiobjective optimization: Application to a sludge drying operation

“…For processes already in operation or for studies focused only on products, the energetic efficiency of the drying stage is often directly linked to the control procedure of the operating input parameters (Banga et al, 2001;Zorrilla et al, 2003;Dufour, 2007). As far as drying processes are concerned, many authors use the response surface method, obtained by design of experiments, in order to realize afterwards a tuning of the optimal parameters through the use of a desirability function (Karimi et al, 2012;Silva et al, 2013;Erbay et al, 2014;Patil et al, 2014).…”

Effects of different objective functions on optimal decision variables: a study using modified complex method to optimize hamburger cooking

“…Any optimization problem has three parts: an objective function to compare the alternatives, a set of constraints to accomplish (e.g., lower and higher limits of the processing temperature and/or accumulated coldest point lethality during processing) and decision variables (process temperatures) to create the alternatives. Thermal processing of foods may be attributed as a problem where the optimization problem is, as stated by Banga, Pan and Singh (2001), a dynamic optimization problem. The term ''dynamic'' comes from the ordinary and partial differential equations describing the process with appropriate initial and boundary conditions.…”

“…Dynamic optimization problems are also called optimal control problems since only the initial state of the system is considered to compute the optimal control. The general optimal control problem may be stated as finding the control variable to maximize (or minimize) the objective function subjecting to the equality and/or inequality constraints and upper and lower bounds for control variables and constraints (Banga et al, 2001). These problems are especially difficult to solve because of the non-linear and distributed nature of the system dynamics and the existence of explicit and implicit constraints on both control variable and objective function (Banga et al, 2001).…”

“…The general optimal control problem may be stated as finding the control variable to maximize (or minimize) the objective function subjecting to the equality and/or inequality constraints and upper and lower bounds for control variables and constraints (Banga et al, 2001). These problems are especially difficult to solve because of the non-linear and distributed nature of the system dynamics and the existence of explicit and implicit constraints on both control variable and objective function (Banga et al, 2001). There have been numerous methods suggested for this kind of problem and accumulated knowledge in the literature (Gallardo & Casares, 1991;Noronha, Hendrickx, Suys, & Tobback, 1993;Banga & Seider, 1996;Kazmierczak, 1996;Noronha, Loey, Hendrickx, & Tobback, 1996a,b;Terajima & Nonaka, 1996;Banga, Perez-Martin, Banga, Alonso & Singh, 1997;Chalabi, Van Willigenburg, & Van Straten, 1999;Banga et al, 2001;Balsa-Canto, Alonso & Banga, 2002;Erdogdu & Balaban, 2002).…”

“…Convergence difficulties may also appear due to the high-linear and/ or discontinuous nature of the thermal processing systems (Banga et al, 2001). Variable process temperatures have been suggested as alternatives in the food sterilization processes.…”