Derived-Rate Increment Stabilization: Its Application to the Attitude Control Problem

Abstract

A gyro-free nonlinear attitude control system for a spacecraft is analyzed. On-off jet actuators are used. Hysteresis and a dead zone are intentionally put into the system. Under certain conditions the feedback signal in the control system is proportional to an angular velocity increment of the system. This is called the derived-rate increment feedback signal. The analysis for a single axis of the attitude control system is given in two parts. One part is concerned with the performance of the system in a limit cycle. The other part discusses the convergence to a limit cycle after a disturbance has occurred. Experimental results verify the results of the analysis. Typical results show the performance of the system during convergence to and operation in a limit cycle. Although the technique is described for use in an attitude control system, it can be successfully employed in other applications.