A TWO-DEGREE-OF-FREEDOM LINEAR ENCODER FOR MEASUREMENT OF POSITION AND STRAIGHTNESS

摘要

A new displacement sensor, the two-DOF linear encoder, is proposed to measure not only the X-directional position but also the Z-directional straightness of a linear stage. The prototype of the two-DOF linear encoder is developed experiments are carried out to evaluate basic performances of the sensor. The working distance is approximately 5 mm. Interpolation error is about ±1 %, which is equal to approximately ±16 nm and ±3 nm as X- and Z-displacements respectively. Resolution is under 0.5 nm in the X- and Z- directions. Future work is measuring of the X-directional position and the Z-directional straightness of the precision linear stage.