ARCTIS

Periodic control of a rotor with a shape-adaptive camber mechanism

Active rotor systems offer additional degrees of freedom compared to conventional helicopter rotors, enabling the achievement of additional control objectives such as performance and noise reduction. These goals contribute significantly to the eco-efficiency of helicopters. The ARCTIS project investigates and develops an active mechanism for changing the blade camber (so-called morphing) for rotor blades for this purpose. The Hochschule München contributes its expertise in the area of robust and periodic control of aeroelastic rotor systems to improve efficiency and suppress disturbances.

The control of the active camber mechanism explicitly takes into account the periodicity of the rotor. This is expected to unlock additional potential compared to classical controller designs, which are often simplified based on a linear time-invariant representation of the rotor system. Metrics are being developed to estimate noise and performance objectives, as robust determination of these quantification parameters on board flying helicopters is not yet fully developed. These metrics are being designed with the aim of being determinable using helicopter sensor data that can be measured during actual flights. Depending on the flight environment and mission elements, the controller should ensure the achievement of the primary emission target.

For example, near the ground, noise exposure to the population will be targeted for reduction, while in cruise flight, fuel consumption will be reduced to increase rotor efficiency. The goal is to achieve a 7% performance savings using the chosen control strategies, even in the presence of disturbances such as atmospheric turbulence. Furthermore, the rotor will be aerodynamically optimized to further enhance the performance savings and noise reduction potential. Since the reference rotor blade used so far was not designed for the integration of structural morphing, there is additional potential for improving efficiency.

In summary, the Munich University of Applied Sciences' part in the ARCTIS project deals in particular with the following aspects:

• Controller design for periodic systems to optimise the active rotor
• Comprehensive aeroelastic validation of the closed control loop
• Development of an actuator controller to optimise the efficiency of the CFD/FEM calculations
• Development of novel analysis methods for periodic systems