Transformations of Optimal Control Problems

The paper considers such transformations of variational and optimal control problems (by a change of phase variables) that help to get the solution. Among these techniques are methods of the dimensionality reduction by a transition from an original argument to a new one, by a detection of a variable staying unchanged through equations of the system (invariant), by extension of the original problem and a transition from it to a simpler problem that gives an estimate solution of the original one. In some cases we can get a solution that is simplified by a transition from a set of conditions in the form of differential equations to the only integral condition. This relates to equations with a retarded argument. The paper gives examples of application of these techniques to real engineering problems such as an optimal control of biosynthesis, cooling of crystal systems by a laser radiation, etc.