Some Trials on Non-contact Operation Control of Mechanical Vibration

This paper presents an outline of the experiments as well as the theories on some new ideas for reducing undesirable mechanical vibrations. A Hall-element is used as a non-contact sensor under the magnetic field of a strong permanent magnet attached to the vibrating body. The voltage output of the Hall-element is supplied to an operation circuit in order to modify and amplify the vibration signal into some desired form of damping force, which is fed back to the original vibrating body through a flat coil type electro-magnetic device. The following four kinds of damping are tested in the experiments: (1) Integrated force of vibration displacement, (2) force proportional to the vibration displacement with opposite sign, (3) Coulomb's type damping, and (4) the square damping whose amplitude is proportional to that of the vibration. The experiments and the calculations showed the good coincidence and proved effectiveness of vibration control.