Machining, Measurement, and Control Laboratory

Measurement of Distance between Two Balls with Rotary Encoder
Fumiya Sakamoto, Iwao Yamaji, Daisuke Kono, Atsushi Matsubara

In order to measure the motion accuracy of machine tools, new instrument measuring distance between two balls is developed. The developed instrument consists of two bars with a ball at one end. The other ends of the bar are linked like a compass. The distance between the two balls is obtained from the length of the bar and the angle between the bars. For measuring the relative displacement between the spindle head and the table of the machine tool, one ball is attached to the spindle head and the other ball is attached to the table. First, parameters required for measurement are identified in this paper. Then, the developed instrument is compared with a laser interferometer for accuracy verification. The standard deviation of the displacement measured with the developed instrument is about 0.35 Ám and larger than that with the laser interferometer. The measurement accuracy of the developed instrument is influenced by the measurement range.
Key words: