Variable Stability In-Flight Simulator Test Aircraft Research Articles

A Flight Test Evaluation of the Arc Segment Attitude Reference for Use as a Primary Flight Reference in Helmet-Mounted Displays

The objective of this evaluation was to determine if the use of the Arc Segment Attitude Reference (ASAR) symbology in a head-up display (HUD) in place of the legacy climb-dive ladder attitude reference aids in unusual attitude recovery (UAR) piloting tasks as specified in AFM 11–217 for use as a primary flight reference (PFR). Flight tests were conducted at the US Air Force Test Pilot School (TPS), Edwards AFB, California on the NF-16D Variable-stability In-flight Simulator Test Aircraft (VISTA). Five VISTA flight UAR test sorties were flown. The time for the pilot to initiate a recovery was measured in addition to the correctness of the recovery. The flight tests were conducted with the use of the HUD combiner on VISTA to examine three symbology configurations. Each of the symbology configurations, the Mil-Std-1787C HUD, dual-articulated (DA) HUD, and ASAR HUD were evaluated by five pilots for the UAR task. The flight test results revealed the ASAR resulted in faster stick input for correction of UARs then the Mil-Std-1787C HUD. This study along with other supporting research indicates that the configural design properties of the ASAR support the ability of pilots to quickly ascertain aircraft attitude.

A Robust Gain-Scheduling Example Using Linear Parametervarying Feedback

A gain-scheduling approach for uncertain Linear Parameter-Varying (LPV) systems with fixed linear fractional relationships on a parameter set is developed. The approach combines LPV theory based on Linear Matrix Inequalities (LMIs) and μ-synthesis to form a new robust approach for large envelope control design. The new approach is used to design an automatically gain-scheduled pitch-rate controller for the F-16 Variable Stability In-Flight Simulator Test Aircraft (VISTA). The ability of the approach to generate controllers for predicted Level 1 flying qualities is illustrated with a high fidelity nonlinear simulation.

Full envelope multivariable control law synthesis for a high-performance test aircraft

A full envelope multivariable flight control system is developed for the Variable Stability In-Flight Simulator Test Aircraft (VISTA). Separate control laws are designed for the longitudinal and lateral directional axes. Output feedback controllers with integral error feedback are created using linear quadratic synthesis and simple linear transformations. Longitudinal stick inputs are used to generate an angle-of-attack command at low-dynamic pressure and a normal acceleration command at high-dynamic pressure. Lateral stick inputs are used to generate a stability axis roll rate command, and rudder pedal inputs are used to generate a sideslip command. Linear point designs are integrated into a gain schedule to create a full envelope nonlinear control system. Flying qualities are evaluated according to military standards and shown to be satisfactory for a wide operating envelope. Classical gain and phase margins and analysis of the structured singular value show robustness to be acceptable for a wide operating envelope.