Real-Time Trajectory Optimization for Noise Abatement of Helicopter Landings

Abstract

In this study, an optimization method is developed to reduce the ground noise impact of helicopter approach flights, and flight experiments are conducted to confirm the effectiveness of this optimization. First, we build a noise model of the JAXA (Japan Aerospace Exploration Agency) experimental helicopter based on measurement results. Then, we define optimal control problems to minimize the noise levels measured at points on the ground surface. The main objective of this paper is to propose a real-time flight trajectory optimization method for solving the optimization problems using actual flight conditions with an on-board computer. To validate the effect of the proposed method, some numerical simulations are conducted under real flight experiment scenarios. The obtained optimal solutions are characterized by steep flight path angles so as to avoid the flight conditions that generate large noise, avoidance of the measurement points, and short flight times; these optimal flights are different from conventional flight trajectories. Finally, the validity of the proposed optimization method is examined by means of flight experiments with the experimental JAXA helicopter. The actual flight experiments result in noise reduction, and prove the effectiveness of the optimization.