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.
Fard
M A
MA
Graduate School of Information Sciences, Tohoku University, Aobayama 01, 980-8579 Sendai Miyagi, Aoba-ku, Japan. fard@mail.nissan.co.jp
Ishihara
T
T
Inooka
H
H
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