New Method for Electro-Mechanical Actuators: Toward Realization of Zero-Emission Aircraft

What is it about?

Reducing wing drag is essential for improving energy efficiency, even in electric or hydrogen-powered aircraft designed for zero carbon emissions. Therefore, aircraft manufacturers seek actuators capable of reducing wing thickness. Manufacturing thinner actuators requires redundant systems comprising multiple units connected in parallel to share the applied load. However, Electro-Mechanical Actuators (EMAs) can experience jamming failure, whereby the drive unit becomes stuck and renders the actuator inoperable. This prevents the realization of a system that uses multiple EMAs. To resolve this issue, we have devised a new type of EMA that handles jamming failure on its own. This simple system does not require brakes or clutches, which are typically necessary in conventional redundant systems. In other words, this EMA enables the construction of an electric actuator system capable of reducing wing thickness, thereby contributing to achieving zero-emission aircraft.

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Photo by Emiel Molenaar on Unsplash

Photo by Emiel Molenaar on Unsplash

Why is it important?

Estimation of EMA failure rate using fault tree analysis (FTA) showed that the failure rate of a conventional EMA with a simple structure was 90.377×10^-6 Failures-Per-Hour (FPH). Meanwhile, the failure rate of the new EMA that we devised was 6.474×10^-6 FPH, which is approximately 1/14 of the failure rate of the conventional EMA. Furthermore, when assuming a system in which two EMAs are connected in parallel, this failure rate becomes ( 6.474×10^-6 )^2 ≈ 4×10^-11 FPH. This means that the electric actuation system can achieve the 10^-9 -scale failure rate that is required for aircraft.