Differential control systems transformations to approximate optimal control search

It is shown that general differential control system may be transformed to equivalent systems with linear control variables. Transformations to derived systems of lesser order known in the theory of degenerate problems are applicable to these systems. Derived problems deliver ideal turnpike solutions to the original problem.
There are proposed procedures of ideal turnpike solution approximations by the admissible original problem solutions for both unbounded and bounded linear controls, and algorithms of their subsequent iterative improvements, applied to some practical problems. (In Russian).