Performance Optimization of a Rotor with Chord Morphing Blades using Particle Swarm Optimization

Abstract

The goal of this report is to minimize the power needs of a helicopter rotor. An introduction to helicopter theory is given, discussing the optimal blade geometry of the hovering rotor. An overview over current methods of performance improvement through rotor blade morphing is given, focusing helicopter chord morhing. The problems of helicopter blade design for a morphing chord length are described and the need of an optimization is elaborated. A brief overview of different optimization techniques is given with focus on nature-inspired algorithms, especially the particle swarm algorithm (PSO). A multi variable, multi objective PSO is implemented in MATLAB and validated with the ROSENBROCK function and a simple rotor morphing scenario. Three missions are chosen and optimized in terms of power consumption, blade loads and rotor hub vibrations normalized with values of the hovering baseline rotor. The optimal parameters for the morphing mechanism and their power saving potential for multiple velocities during these missions are provided. The influence of the geometry and structural changes of the chord morphing rotor on the morphing parameters (especially the hinge location) are discussed. An optimal hinge location is found to be close to the blade tip for power and blade load reduction, while in the inbound regions for vibration reduction.