Article ID: | iaor1995319 |
Country: | United Kingdom |
Volume: | 15 |
Issue: | 2 |
Start Page Number: | 77 |
End Page Number: | 100 |
Publication Date: | Apr 1994 |
Journal: | Optimal Control Applications & Methods |
Authors: | Arora J.S., Lin T.C. |
Keywords: | control processes |
Continuous- and discrete-time differential dynamic programming (DDP) approaches to solve general optimal control problems are described and analysed. A comparison of the two approaches shows the continuous-time approach to be more general and flexible compared with the discrete-time approach, since it is not tied to any discretization scheme. A comparison of DDP with the non-linear programming (NLP) approach is also given. Three structural control problems-a linear model of a space structure, a single degree of freedom non-linear impact absorber and a non-linear flexible beam subjected to an impulsive load-are used to numerically evaluate the continuous- and discrete-time DDP approaches. Several grid sizes are used to show that the continuous-time approach with a reasonable number of grid points is more accurate and efficient (in most cases) than the discrete-time approach. It is therefore recommended to fully develop and evaluate the technique for the optimal control of large-scale systems.