IMPROVED TUNNEL DISPLAY FOR CURVED TRAJECTORY FOLLOWING - EXPERIMENTAL EVALUATION

Improvements of a previously developed tunnel display for curved traje ctory following have been experimentally evaluated. A fixed-base simul ator study has been carried out, in which eight pilot subjects flew a simplified linearized trim model of a large transport aircraft along e ight different curved and descending approach trajectories under vario us experimental conditions. The purpose of this study was to evaluate an new predictor guidance scheme based on an actively driven predictor reference window, The results showed that, for the larger prediction times, the new guidance scheme yielded a superior performance as compa red to the original configuration, in which a nonactive predictor refe rence window was used. Corner cutting, as experienced in earlier confi gurations, was eliminated, resulting in a highly improved positional a ccuracy in transitions from straight to curved trajectory sections and back. Furthermore, cross track errors, resulting from low-frequency d isturbances, such as slow-varying crosswinds, were greatly reduced as a result of the integral control action imparted to the predictor refe rence window without affecting the task difficulty. Subject response h as been found to strongly resemble the one of a well-designed autopilo t.