Open Loop Control of a Control Surface Actuation System

摘要

A mathematical model of a torpedo control surface actuation system was used to study whether the control surfaces can be reliably and accurately controlled, for time periods less than 1 min, by the on-board digital computer, without rotor position feedback, i.e., open-loop control. Two control algorithms were investigated: amplitude-modulated step demands, where the demand output from the on-board computer to the servo valves is modulated on the basis of known actuator performance; and parallel closed-loop model, where a representation of the closed-loop actuator is stored in the on-board computer and used to provide an equivalent position feedback to the servo valve, driving the open-loop actuator. Time and frequency response studies demonstrate that both methods can provide accurate short term control of the system. Drift can be kept to acceptable levels for short duration missions.