Development of a multi-axis active seat mount to mitigate vibration transmission to helicopter aircrew

This paper presents the performance evaluation of a multi-axis active helicopter seat mount. By simultaneously counteracting vibrations in three orthogonal directions, the mount mitigates the transmission of helicopter vibrations from the floor to the seat before reaching to the human body. This design is tested independently in each direction and simultaneously in all three directions using shaker tables. The input vibration prole used in these tests are helicopter flight measurements collected on a Bell-412 research helicopter. To cancel the input vibration, the feedforward Filtered-x Least Mean Square (FxLMS) algorithm is employed as the adaptive control law. Signicant suppression of the harmonic components of the N/rev harmonics is achieved for both independent and simultaneous testing. In each case, the overall g-rms reduction level is more than 40 % along each axis. The experimental testing veried the effectiveness of the active seat mount as a means to attenuate multi-axis vibrations experienced by helicopter aircrew.Peer reviewed: YesNRC publication: Ye