This book is devoted to new methods of control for complex dynamical
systems and deals with nonlinear control systems having several degrees
of freedom, subjected to unknown disturbances, and containing uncertain
parameters. Various constraints are imposed on control inputs and state
variables or their combinations. The book contains an introduction to
the theory of optimal control and the theory of stability of motion, and
also a description of some known methods based on these theories. Major
attention is given to new methods of control developed by the authors
over the last 15 years. Mechanical and electromechanical systems
described by nonlinear Lagrange's equations are considered. General
methods are proposed for an effective construction of the required
control, often in an explicit form. The book contains various techniques
including the decomposition of nonlinear control systems with many
degrees of freedom, piecewise linear feedback control based on
Lyapunov's functions, methods which elaborate and extend the approaches
of the conventional control theory, optimal control, differential games,
and the theory of stability. The distinctive feature of the methods
developed in the book is that the c- trols obtained satisfy the imposed
constraints and steer the dynamical system to a prescribed terminal
state in ?nite time. Explicit upper estimates for the time of the
process are given. In all cases, the control algorithms and the
estimates obtained are strictly proven.