Global robust stabilization of nonlinear systems subject to input constraints

Our main purpose in this paper is to further address the global stabilization problem for affine systems by means of bounded feedback control functions, taking into account a large class of control value sets: p, r-weighted balls B-r(m) (p), with 1 < p less than or equal to infinity, defined via p, r-weighted gauge functions. Observe that p = infinity is allowed, so that m-dimensional r-hyperboxes B-r(m)(infinity) := [-r-(-)(1), r(1)(+)] x... x [-r(m)(-),r(m)(+)] r(j)(+/-) > 0 are also considered. Working along the line of Artstein-Sontag's approach, we construct an explicit formula for a one-parameterized family of continuous feedback controls taking values in B-r(m)(p) that globally asymptotically stabilize an affine system, provided an appropriate control Lyapunov function is known. The designed family of controls is suboptimal with respect to the robust stability margin for uncertain systems. The problem of achieving disturbance attenuation for persistent disturbances is also considered. Copyright (C) 2002 John Wiley Sons, Ltd.