Satoshi Yonezawa

Simultaneous structure/control design optimization of a wing structure with a gust load alleviation system

Simultaneous design optimization is considered for structure and control parameters of a wing with a gust load alleviation (GLA) control system. The application of a goal programming (GP) formulation to the design synthesis of an aeroservoelastic system is carried out by the use of a simple mathematical model in conjunction with a wind-tunnel model having a GLA control system. Numerical applications are based on a cantilever wing having an aileron surface controlled by wing-tip accelerometer feedback signals. System equations are obtained in the form of state equations, thus enabling the statistical characteristics of both the gust-induced wing stress and the control surface deflection angle to be evaluated using their standard deviations. The wing spar height and the controller feedback gain are simultaneously optimized to obtain the minimum spar weight while satisfying the following structure and control design constraints: 1) the spar stress is limited with the control system either on or off; 2) the control surface deflection angle is restricted; and 3) system stability should be guaranteed by incorporating a controller stability margin. Numerical examples demonstrate the successful application of a GP formulation for the simultaneous structure/control design synthesis by specifying priorities to the conflicting design constraints.

Online Four-Dimensional Flight Trajectory Search and its Flight Testing

Online flight trajectory optimization algorithms are developed in order to guide and control aircraft for emergency landing. Further, the applicability of generated flight trajectories to real flights is evaluated using a flight simulator and an experimental aircraft. By combining the real-time A* path search algorithm with the R-TABU optimization method and an inverse dynamic method, a near-optimal four-dimensional flight trajectory is computed in real time. The proposed method is applied to design a flight trajectory for emergency landing. The generated flight trajectory is shown to pilots as a tunnel-in-the-sky image in order to track the trajectory by manual operation. Both the simulation and flight experiments refine the algorithms and demonstrate the applicability of the proposed system.

A Study on Online Flight Trajectory Search and its Flight Simulator Testing

[Abstract] Real -time flight trajectory optimization algorithms are developed and evaluated through numerical simulation and flight simulator testing. The purpose of this study is to guide and control an aircraft in emergency landing. Though our final goal is to develop an automatic control system for tracking flight trajectories generated with the online optimization, this study verifies the validity of the generated optimal trajectories with manual flight control. This paper considers the real-time direct trajectory optimization method that can deal with constraints more strictly.