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 flight control system (Micro-DFCS) installed in Princeton’s Variable-Response Research Aircraft (VRA). These control laws were designed using linearquadratic, sampled data regulator theory, and 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 by increased sampling delay. Type 0 controllers provided satisfactory performance in flight, but the equivalent Type 1 systems were found to be unduly sensitive to disturbances and measurement noise.