Maintaining attitude error constant in Euler singularity protection

摘要

A model-following aircraft control system in which a roll rate command in Euler coordinates is integrated to provide a bank angle command, which has actual bank angle subtracted therefrom to provide a command error that is converted back to aircraft body coordinates for use, so long as the pitch attitude of the aircraft does not approach zenith or nadir. But, while the absolute value of the pitch attitude exceeds 85° the last error generated before exceeding 85° is converted to body coordinates for use by the aircraft, and the initial integrated value of attitude command, for use when the pitch angle reverts below 85°, is formed as the sum of said last error and the actual attitude angle of the aircraft.