![]() ![]() Numerical simulations are presented highlighting the strengths and weaknesses of the method.The technology has been around for decadesġ958 The Avro Canada CF–105 is the first non-Experimental aircraft with fly-by-wire controls.ġ964 The Apollo Lunar Landing Research Vehicle is the first fly-by-wire aircraft without a mechanical backup. The closed loop time integration is accomplished using an implicit modifled Newmark method. Difierences between the desired and actual trajectories are handled in the nonlinear outer-loop using traditional proportional-integral-derivative design guidelines. For the longitudinal motion Dynamic Inversion is utilized. Control of the inner-loop lateral motion is accomplished using a standard Linear Quadratic Regulator. Dominant kinematic nonlinearities are handled in the outer-loop while the inner loop is further separated into a lateral and longitudinal motion. This approach separates the problem into two parts: a fast inner-loop and a slower outer-loop. To accomplish this a heuristic approach based upon pilot behavior is developed. The ∞exibility must be accounted for directly in the controller development. This creates a coupling which cannot be separated by previous control schemes. Due to the inherent ∞exibility of the aircraft modeling, the low order structural frequencies are of the same order as the rigid body modes. The geometrically nonlinear structural formulation, the flnite state aerodynamic model, and the nonlinear rigid body equations together provide a low-order complete nonlinear aircraft analysis tool. The nonlinear beam flnite element structural model assumes constant strain over an element in extension, twist, and in/out of plane bending. ![]() A low-order strain-based nonlinear structural analysis coupled with unsteady flnite-state potential ∞ow aerodynamics form the basis for the aeroelastic model. The 6-DOF equations of motion of a reference point on the aircraft are coupled with the aeroelastic equations that govern the geometrically nonlinear structural response of the vehicle. Numerical simulations are presented highlighting the strengths and weaknesses of the method.read more read lessĪbstract: This paper focuses on trajectory control of the 6-DOF body flxed reference frame located on a very ∞exible aircraft. Abstract: This paper focuses on trajectory control of the 6-DOF body flxed reference frame located on a very ∞exible aircraft.
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