Fast implementations and rigorous models: Can both be accommodated in NMPC?

Victor M. Zavala, Carl D. Laird, Lorenz T. Biegler
2008 International Journal of Robust and Nonlinear Control  
In less than two decades, Nonlinear Model Predictive Control (NMPC) has evolved from a conceptual framework to an attractive, general approach for the control of constrained nonlinear processes. These advances were realized both through better understanding of stability and robustness properties as well as improved algorithms for dynamic optimization. This study focuses on recent advances in optimization formulations and algorithms, particularly for the simultaneous collocation-based approach.
more » ... ere we contrast this approach with competing approaches for on-line application and discuss further advances to deal with applications of increasing size and complexity. To address these challenges we adapt the real-time iteration concept, developed in the context of multiple shooting [9, 5] , to a collocation-based approach with a full space nonlinear programming solver. We show that straightforward sensitivity calculations from the KKT system also lead to a real-time iteration strategy, with both direct and shifted variants. This approach is demonstrated on a large-scale polymer process, where on-line calculation effort is reduced by over two orders of magnitude.
doi:10.1002/rnc.1250 fatcat:vl52vgx6kjg25j5iaorawr7x7a