Implementation of Pilot Commands in Aircraft Control: A New Approach Based on Dynamic Inversion

Abstract

Using the principle of dynamic inversion, a new control synthesis approach is presented for implementing the pilot commands in aircraft control. The command inputs from the pilot are assumed to be (i) the normal acceleration and forward velocity commands in the longitudinal mode (roll rate command being zero) and (ii) roll rate, height and forward velocity commands in the lateral mode. Turn coordination criterion requirement leads us to fix the lateral acceleration command as zero. Unlike an existing technique where the normal and lateral acceleration commands are first transformed into pitch and yaw rate commands respectively, in the new approach there is no such requirement in the longitudinal mode. In the lateral mode, however, only the height command is first transformed into pitch-rate command before the control is computed. Unlike the existing procedure, the new straight forward approach leads to a number of advantages; namely lesser oscillatory response, lesser control magnitude and lesser number of design parameters. In a comparison study with the existing method using the Six-DOF model for Boeing 747 (a transport aircraft), numerical results clearly show the improved performance of this new approach.