The analysis of subdivision measurement based on sinusoidal magnetic field model

A new space subdivision algorithm for the application object like linear motor whose magnetic flux density of magnetic field is sinusoidal was proposed. Space sinusoidal and cosine signals can be obtained by two sensors whose distance equals a quarter of magnetic polar pitch. By continuously doubling the measured signals’ frequency by sinusoidal and cosine operation, a set of orthogonal signals were produced whose equivalent pole pitch equals half of previous signals’. Using an electronic comparator to detect zero crossings, quadrature binary pulses may in turn be obtained from the frequency doubled signals and high-speed, high-precision displacement measurement can be achieved. By analyzing the signal’s signal to noise ratio, subdivision multiples’ constraints when zero crossings detection is available can be obtained. Experimental results showed the effectiveness of this subdivision method.

► The algorithm which was proposed in this paper is ingenious and easy-achieved.
► The transfer law of measurement noise is a wonderful and simple result.
► This algorithm can be applied in all the objects has sinusoidal characteristics.