Self Calibratable Angle Measurement Equipment is an ultra precision rotary encoder which can calibrate graduation position deviation itself without comparing to standard rotary encoder by using The Equal-Division-Averaged (EDA) Method..
Self Calibratable Angle Measurement Equipment can calibrate itself by placing reading heads on single rotary encoder which are traditionally allocated to two rotary encoders in existing Comparative Angle Measurement Equipments.
Figure 3 Concept of Self Callibratable Angle Measurement Equipment
Figure 3 shows Conceptual model of Self Calibratable Angle Measurement Equipment with five reading heads (j=0,1,2,3,4) which are arranged at equal angle interval around the scale disk of one rotary encoder.
Relative positional deviationδi＋2πj/5 between reference reading head (j=0) and other reading heads (j=1,2,3,4) and their average valueμi are expressed as (4) and (5) respectively.
Here, the second term on the right side can be considered as 5th-order Fourier components of ai+0 owing to The Equal Division Averaged (EDA) Method.
Accordingly, if 5th-order component is small enough, measurement value μi can be calibration curb.
Figure 4 shows calibration curb of relative positional deviation of five reading heads and reference reading head (j=0).
Figure 4 Calibration Curve
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Self Calibratable Angle Measurement Equipment
