Abstract
With development of time grating technology in the past 10 years, the theory of using time to
measure spatial displacement has been completed greatly. In the study of time grating, one novel
linear displacement sensor is proposed based on the measurement principles of time grating. The
measurement principles of linear displacement are similar to that of angular displacement. Both of
them need one endless coordinate with uniform velocity. The theory of linear AC motor is used, and
the three-phase winding with equal division space of 120° and three-phase exciting signal with
uniform time are utilized to generate the endless moving coordinate with uniform velocity. The
magnetic traveling wave arises from the left endpoint and disappears in the right endpoint, and it
travels pole pitch distance of W during the periodic time of T with the uniform velocity. When
magnetic traveling wave passes by the static probe and the moving probe, the electric signals will be
induced on the winding, respectively. Therefore, the linear displacement can be achieved by
comparing the phase between the two output induced signals from he static probe and the moving
probe. Furthermore, in order to improve the machining technique, four kinds of winding framework
are designed to employ. The experimental results show that advantages and disadvantages both exist
in the design methods and the precision of experiment results reaches ±2μm. The next study plan is
to choose the most excellent design method through further experiments and improve the precision
of displacement sensor greatly.
