Fuzzy guidance of the shuttle orbiter during atmospheric reentry

The guidance law for the Space Shuttle Orbiter is required to track a reference state trajectory satisfying a given drag-acceleration versus velocity profile. Newly available nonlinear guidance laws will require complicated multi-dimensional interpolation. In this paper, Sugeno approximators (hybrid fuzzy-crisp inference systems) trained by example are used to conduct this interpolation. Moreover, the concept of surface-tracking guidance is introduced in which the reference trajectory itself is updated when severe disturbances warrants it. Surface tracking requires an "on-line optimizer" which is implemented using a constellation of a few blocks, two of which are multi-input/multi-output Sugeno approximators. The different approximators and guidance laws have been studied and simulated. © 1999 Elsevier Science Ltd. All rights reserved.