Optimal Control of Nonlinear Chemical Processes Using the Variational Iteration Method

In this paper, a design approach of an optimal control of nonlinear chemical processes is proposed. The idea consists in adopting the variational iteration method to solve the non-linear Hamilton equations derived from the minimum principle theory. These equations constitute a two-point boundary value problem with a coupled nature of solutions. Thus, by considering the correction functionals of the Hamilton equations, the Lagrange multipliers are easily identified and practical iteration formulas are derived. Based on this formulas, an algorithm is developed to determine iteratively the solutions of the Hamilton equations with a desired accuracy. Once the solutions are obtained, the optimal control law can be easily deduced. The design approach is illustrated by two examples from chemical engineering. Copyright c ©2012 IFAC.