A Search for the Minimum-Fuel Landing Trajectory of a Tilt-Wing VTOL Aircraft.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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Optimal control techniques are used to find the minimum-fuel landing trajectory of a tilt-wing VTOL aircraft. A fourth-order, nonlinear, mathematical model of the XC-142A was used, employing three controls wing incidence, thrust and a limited authority pitch control. Optimization was accomplished by the conjugate gradient method using penalty functions to control terminal error and constrained variables. A control variable transformation was used to constrain the controls. To start the optimization algorithm, initial controls were computed to perform a landing trajectory with the model without exceeding the constraints. The increase in computing time due to the transformation was negligible. Convergence to terminal conditions was hindered by a wing lift anomaly. Author
- Transport Aircraft