The noise produced by helicopters, particularly as they come into land, is far from pleasant, and their vibrations also affect the pilot. Noise and vibration are caused by the air currents in the plane of the rotors. Noise is generated when one rotor blade collides with the vortex trail of the rotor blade in front. One way to reduce the noise emissions as well as the overall vibrations of a helicopter is to use additional, piezoelectrically controlled flaps in the rotor blades.
A SCALEXIO AutoBox with a processor board and an FPGA board is the optimal prototyping system for noise and vibration reduction applications. It has enough processing power to provide the fast control of the multiple piezo actuators per rotor that control the flaps’ angle of attack. The input for the control strategy comes from pressure sensors in the rotor blades and additional microphones on the landing skid, which measure the air pressure curves. Synchronous preprocessing of multiple channels can be conducted on the FPGA board without any impact on the processor board. Because the prototyping system has a modular setup, it can be flexibly scaled in case more microphone channels or more piezo actuators are needed. Model-based development of the control strategy is not only possible on the processor board but also on the FPGA board if very short response times are required.