Identification of the head-neck complex in response to trunk horizontal vibration.
A method is proposed for identifying the head-neck complex (HNC) in the seated human body when it is exposed to the trunk horizontal (fore-and-aft) vibration. It is assumed that the HNC only has the anteroposterior (flexion/extension) motion in the sagittal plane. An electrohydraulic vibrator is used as a source of vibration. To generate the trunk horizontal vibration, the trunk of the seated subject is fixed to the seatback. The subjects are exposed to the random vibration at a magnitude of 1.60 ms(-2) rms (root-mean-square) for 50 s. The coherence and frequency response function are then obtained in the frequency range 0.5-3 Hz. The results show that the HNC behavior is quasilinear with a resonance frequency between 1 and 1.4 Hz. Accordingly, a two-dimensional single-inverted pendulum is considered as a model for the HNC. The frequency domain identification method is then used to estimate the unknown parameters, including the HNC viscoelastic and inertia parameters. The model is examined in a time domain using the random vibration. Good agreement is obtained between experimental and simulation results, indicating the reliability of the proposed method.
Graduate School of Information Sciences, Tohoku University, Aobayama 01, 980-8579 Sendai Miyagi, Aoba-ku, Japan. fard@mail.nissan.co.jp
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Ishihara
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Inooka
D000054:Acceleration; D000328:Adult; D004548:Elasticity; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D009039:Motion Perception / Q000502:physiology; D009041:Motion Sickness / Q000209:etiology / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology; D009334:Neck Muscles / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology; D011434:Proprioception / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D012018:Reflex / Q000502:physiology; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D014732:Vibration