Accession Number : ADA320260

Title :   High Angle of Attack Short Period Flight Control Design with Thrust Vectoring.

Corporate Author : WRIGHT LAB WRIGHT-PATTERSON AFB OH

Personal Author(s) : Hammett, Kelly D. ; Reigelsperger, William C. ; Banda, Siva S.

PDF Url : ADA320260

Report Date : 1994

Pagination or Media Count : 6

Abstract : A manual flight control system for the short period dynamics of a modern fighter aircraft incorporating thrust vectoring at high angles of attack (a) is presented. Design goals are posed in terms of maintaining acceptable flying qualities during high a maneuvering while also achieving robustness to model parameter variations and unmodeled dynamics. An inner loop dynamic inversion/outer loop structured singular value (tt) - synthesis control structure is used to separately address operating envelope variations and robustness concerns, respectively, eliminating the need for gain scheduling. Angle of attack command following performance objectives are built into both loops. Realistic representations of both structured (real parametric) and unstructured uncertainty are included in the design/analysis process. A flight condition dependent control selector maps generalized controls to physical control deflections, considering actuator redundancy, effectiveness, and saturation issues. Structured singular value analysis, low-order equivalent system (LOES) fits, and linear step responses demonstrate satisfaction of design goals. Effects of including actuator rate and position limits are investigated for an aggressive a doublet command, comparing daisy chained and ganged controls methods. Simulation results suggest a ganged approach offers advantages over daisy chaining at high alpha.

Descriptors :   *FLIGHT CONTROL SYSTEMS, *THRUST VECTOR CONTROL SYSTEMS, SIMULATION, FIGHTER AIRCRAFT, POSITION(LOCATION), UNCERTAINTY, MODELS, SYNTHESIS, DYNAMICS, PARAMETERS, PHYSICAL PROPERTIES, DEFLECTION, RATES, VARIATIONS, SHORT RANGE(TIME), SCHEDULING, LIMITATIONS, RESPONSE, GAIN, MANUAL OPERATION, ACTUATORS, REDUNDANCY, HIGH ANGLES.

Subject Categories : Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE