Each part of the human body has its own natural frequency. For example, for the head, resonances can be observed below 5 Hz in lateral motion as well as in the pitch and roll directions. When seated, resonance of the whole body occurs, where the torso acts as the mass and the seat cushion as the stiffness. Ride comfort is evaluated from the product of these resonance characteristics and the vibration characteristics of the mobility. Vibration-induced movement of the head and line of sight, and vibration of internal organs, are closely related to motion sickness and become important measurement data for enabling everyone to use mobility comfortably.
Muscle usage differs when an automobile driver operates the steering wheel in a relaxed state versus under tension. Even if the operation appears the same, electromyography (EMG) measurements can reveal whether the driver is able to steer comfortably.
In heart-rate measurement, calculating the intervals between beats—known as a Lorenz plot—enables quantification of autonomic nervous activity and estimation of stress levels.
Estech possesses human-body measurement technologies grounded in extensive experience, as well as proprietary technologies for modeling human-body vibration. By leveraging these, we can clarify how people exposed to vibration evaluate comfort and propose design requirements.
