Accelerating genetic optimisation of nonlinear model predictive control by learning optimal search space size

Genetic algorithm (GA) is typically used to solve nonlinear model predictive control's optimisation problem. However, the size of the search space in which the GA searches for the optimal control inputs is crucial for its applicability to fast-response systems. This paper proposes accelerating the genetic optimisation of NMPC by learning optimal search space size. The approach trains a multivariate regression model to adaptively predict the best smallest size of the search space in every control cycle. The proposed approach reduces the GA's computational time, improves the chance of convergence to better control inputs, and provides a stable and feasible solution. The proposed approach was evaluated on three nonlinear systems and compared to four other evolutionary algorithms implemented in a processor-in-the-loop fashion. The results show that the proposed approach provides a 17-45% reduction in computational time and increases the convergence rate by 35-47%. The source code is available on GitHub.