Design and flight test of a lateral-directional command augmentationsystem

Two-input/two-output lateral-directional control laws with Type 0 and Type 1 structures have been designed, analyzed, and flight-tested using the microprocessor-based digital f light control system (Micro-DFCS) installed in Princeton's Variable-Respons e R esearch Aircraft (VRA). These control laws were designed u sing linear-quadratic sampled-data regulator theory, and they were evaluated by U.S. Navy test pilots. Major closed-loop response features were found to be relatively insensitive to sampling rate (down to 4 sps), although flying qualities were degraded b y increased sampling delay. Type 0 controllers provided satisfactory performance in flight, but the equivalent Type 1 systems were found to be unduly sensitive to dkpurbances and measurement noise. A novel application of the Tustin transformation proved useful in control law implementation.