Application of collaborative optimization to optimal control problems

An alternative solution to optimal control problems using collaborative optimization (CO), an MDO method with decomposition strategy, is discussed. A collocation method is used for converting problem into a finite-dimensional nonlinear optimization problem. It is found that to avoid a high-dimensional system-level problem, CO tends to be most effective in weak-coupled problems, problems with few global variables, and the formulation of problem exactly satisfies this requirement. The results show that the objective value of CO is slightly smaller than that of the integrated solution, which is due to the allowed relaxed tolerance (10^-5) of the system-level constraints. There are slight inconsistencies between the system-level target and the responses of the suboptimizations, which are also due to the relaxed tolerance in the system-level constraints.