Figure eight hysteresis control method and follow-up system

Abstract

A control system () operates within a dynamic range, and a follow-up system () is commanded to reduce a positional error between the follow-up system and the control system when the dynamic range is exceeded. A linear follow-up command may be initially provided once a dead band value () is exceeded. The follow-up system () is driven relative to its base mount () in a direction to reduce the positional error to within a null value range (). The follow-up command may also implement a decay function to control the follow-up system (). A control variable transfer function may also be utilized to gradually subtract the dead band value from the follow-up system position error command as a function of time. The decaying function may include linear as well as non-linear decaying functions. In one embodiment, a figure eight-type hysteresis control function may be implemented to control the inertial position of an inertial element. The various embodiments of the present invention may be suitable for space-based laser designating and targeting systems, space-based camera-positioning systems, space-based telescopes, and radar antenna positioning systems.