Norihiro Goto

Direct optimization methods applied to a nonlinear optimal control problem

The paper compares the direct collocation with nonlinear programming method and the quadrature rule scheme in the category of direct optimization methods. It is pointed out that the original quadrature rule scheme produces control discontinuities as the result of discrete computation of the state variables. The paper proposes a modified quadrature rule scheme that combines the original quadrature rule scheme with the idea of control smoothing that characterizes the direct collocation with nonlinear programming method. These direct optimization methods are applied to the problem of dynamic soaring of a glider, formulated as a nonlinear optimal control problem. The solutions by the direct methods excluding the original quadrature rule scheme are consistent, and it is demonstrated that a glider is capable of making an energy balanced flight of dynamic soaring.

IDENTIFICATION OF BLIMP DYNAMICS BY INDOOR FREE FLIGHT TESTS

A blimp is introduced as a stable platform for remote-sensing instruments required for unmanned aerial observation and surveillance. For developing flight control systems of the blimp, a series of experiments has been conducted to identify its flight dynamics. The paper addresses the blimp configuration, the experimental set-up, the method for identifying its dynamics, and the results of the identification in comparison with analytical estimation with respect to their modes. The experimental method employs indoor free flight tests using the full-scale blimp, and the data reduction for the identification uses the least-squares method involving the autoregressive model fitting algorithm. The result suggests that analytical formulas for estimating the parameters including added mass effects and stability derivatives may yield values consistent with experimentally identified ones.