The Design, Development, and Flight Testing of a Modern-Control-Designed Autoland System

This paper discusses the design, development, and flight test results of a full-state feedback modern-controls-designed autoland system--the Digital Integrated Automatic Landing System (DIALS). The lateral and longitudinal control laws were designed by formulating a linear quadratic regulator with disturbances problem. Although the designs were independent of each other, in implementation cross-coupling of the lateral and longitudinal variables does occur. A brief discussion of the control modes--localizer capture, localizer track, decrab, glideslope capture, glideslope track, and flare--and the modifications made to the basic design during the simulation phase to achieve desired performance is given. Some of the efforts required to implement the system in the flight computers and some problems encountered in the ground hardware simulation checkout are discussed. Finally, flight test data is presented for this system which performed 10 "hands off" automatic landings. The flight test data includes the performance of the aircraft in mild, gusty, and wind shear conditions.