Posicast Control of Damped Oscillatory Systems

Abstract

A novel method is presented for producing dead-bea response in a lightly-damped oscillatory feedback system. Complete transient response times of the order of a fraction of the natural oscillatory period can be obtained. Excellent waveshape reproduction is achieved through a linear phase lag with frequency. The method consists of exciting several transient oscillations, at closely spaced times, with magnitudes and phases so adjusted that the resultant sum of the transient oscillation phasors is zero. The steady-state output is the arithmetic sum of the excitation magnitudes. When a step input transient is divided into two spaced excitations, one-half cycle response is obtainable. When the input transient is divided into three excitations, one-fourth period or faster transient times are realizable, depending upon the available dynamic range or signal-to-noise ratio. The principle of design is to adjust a system to the maximum possible resonant frequency, independent of the damping factor, but stable, and then to apply the Posicast control to completely remove the oscillatory component in the output. In an electrical feedback control system, the additional hardware consists of one or two artificial transmission lines.