An optimum bistable controller for increased missile autopilot performance

Abstract

One of the major problems in missile control is the change in missile dynamics caused by changing aerodynamic parameters. The method of control described herein possesses control capability for a wide range of aerodynamic parameters utilizing only information derived from the state variables of the system. Liapunov's second method was used to derive the form of the control signal. The analysis was based on the control of an autonomous, stable plant. However, with only a slight change in the form of the signal, it was possible to stabilize a forced unstable system. The control signal was constructed by summing the weighted states of the plant and using this to trigger a bistable amplifier. The output of the bistable amplifier was summed with the command to the system. The analysis and analog computer study used a 3rd-order linearized model of typical missile dynamics. The computer study has shown that it was possible to control this model for a wide range of aerodynamic parameters. The advantages of this controller over more sophisticated adaptive control systems that might yield similar control characteristics are its simplicity and its all-electrical nature.