METHOD AND APPARATUS FOR MEASURING POSITIONS OF ONE OR PLURALITY OF SHAFT IN NON-CONTATCT STATE

摘要

PURPOSE: To measure a distance between a person and a machine with high accuracy, by using a standard electrode on a standard point and a shaft electrode fixed along a shaft. CONSTITUTION: A bow 8 of a cello is moved along a string 4 by a hand 10 of a cellist. Sometimes the bow 8 is moved near a bridge 6, and sometimes it is moved at the position separated from the bridge 6. The movement in the axial direction has an influence on tone quality. The standard electrode 12 is loaded on the bridge 6 (standard point) as an antenna for transmission. The shaft electrode 14 is loaded on the bow 8 to act as an antenna for reception. A signal generating device 16 is connected with the electrode 12 through a cable 18. A cable 20 connects the electrode 14 and an amplifier 24. The coupling capacity between the electrodes 12, 14 is decided on the basis of the distance therebetween. The output voltage VQ of an amplifier circuit 22 is evaluated by an evaluating means 50 for deciding the position of the bow 6.