Thrust vectoring

Abstract: A decoupled wide envelope lateral/directional axes control design is presented for a supermanoeuvrable version of an F-18 aircraft. A control structure is developed that separates gain scheduling issues from aircraft performance issues. Flight condition dependent state and control effectiveness variations are accounted for by an inner loop controller designed using eigenstructure assignment. Structured singular value synthesis is used to design an implicit model following outer loop controller that addresses flying qualities performance specifications. A control selector is designed that generates lateral/directional aerodynamic and thrust vectoring commands from generalized control inputs of roll and yaw acceleration. Flying qualities and robustness analyses show that the control system performs well despite neglected dynamics and system uncertainties. Nonlinear simulations are presented showing excellent decoupling of roll and yaw responses.

Abstract: The invention discloses an exercise-decoupling axial-symmetry thrust vectoring nozzle adjusting mechanism and belongs to the technical field of aero engines. The exercise-decoupling axial-symmetry thrust vectoring nozzle adjusting mechanism comprises a cartridge receiver, an adjustable ring, a first driven branch, a second driven branch, a third driven branch, a fourth driving branch, a fifth driving branch and a sixth driving branch. The cartridge receiver is taken as a motionless platform F and the adjustable ring is taken as a motion platform M. Two ends of the first driven branch, the second driven branch, the third driven branch, the fourth driving branch, the fifth driving branch and the sixth driving branch are respectively connected with the adjustable ring and the cartridge receiver. The first driven branch and the second driven branch respectively comprise a universal pair, a lower revolute pair and an upper revolute pair connected sequentially in series. The third driven branch comprises an upper revolute pair, a lower revolute pair and a universal pair sequentially connected in series. The fourth driving branch, the fifth driving branch and the sixth driving branch respectively comprise a lower spherical hinge pair, a sliding pair and an upper spherical hinge pair. With the exercise-decoupling axial-symmetry thrust vectoring nozzle adjusting mechanism, pure rotating output of the adjustable ring can be realized, the adjustable ring is not driven by a shaft to rotate when rotating around the shaft, so that the exercise-decoupling axial-symmetry thrust vectoring nozzle adjusting mechanism has the advantages of good exercise-decoupling performance, easy control and the like; the exercise-decoupling axial-symmetry thrust vectoring nozzle adjusting mechanism has less spherical hinge pairs, so that production cost and mounting difficulty are reduced.

Abstract: Multi-Function Nozzles (MFN) will add pitch and yaw thrust vectoring, thrust reversing, and the ability to optimize the nozzle area ratio, to the current nozzle capabilities of throat area control and scheduled exit area control. These new propulsive forces and moments will allow fighters to operate at higher angles, higher angular rotational rates and accelerations, and quicker flight path turn and deceleration rates. A fundamental change in fighter design philosophy will be possible by allowing the MFN's to augment or replace the aircraft's tail surfaces. Fighter affordability will be increased through reduced size and cost, better fuel efficiency, less stringent basing requirements, lower peace-time attrition, and reduced pilot training. Survivability will be enhanced by reductions in detectability, susceptibility, and vulnerability; and fighter mission effectiveness will be augmented by increased air combat capability and reduced ground attack response time. The MFN contributions to the above stated fighter enhancements are elaborated on through the text and figures of this paper.