Prospects for Arms Control

A cascade structure for robust control design

“…This design methodology permits us, in principle, to define several types of robust nonlinear feedback and includes VSC as a where A, > 0 and > 0 are known A4: F~~ t E e, m(t) and n(t) are sign-definite functions with particular limit case [9]. The main advantage of the binary control 11141 < Im(t)I < iii technique, with respect to VSC, is the fact that the control law is a "continuous" function of time, and for this reason, it can be used as a "reference signal" for the "inner" control loop.…”

“…This is true, for example, in the design of optimal, full-order 312 and 31controller design. However, when additional constraints are imposed, such as restrictions on the compensator dimension (see, e.g., [SI- [9]) or certain robustness constraints (see, e.g., [lo], [8]), it is not always possible to find closed-form expressions for the controller of interest. In these cases, it is necessary to synthesize controllers using optimization algorithms [ 111, [6]- [9].…”

“…More specifically, a feedback scheme is suggested for robust stabilization and tracking of second-order nonlinear uncertain dynamical systems. The basic idea is to join the well-known variable structure control (VSC) [6]- [8] and binary control (BC) [9], [lo] in the cascade structure shown in Fig. 1.…”