Rotor displacement measurement device and method for planar motor

Abstract

The invention provides a rotor displacement measurement device and method for a planer motor. According to the method, two sets of magnetic flux density sensors are respectively and uniformly distributed in a field pole polar distance tau in two mutually perpendicular moving directions of a sine magnetic field area formed by a stator magnetic steel array on the planer motor, sampled signals of the four sets of sensors are subjected to frequency multiplication operation by a signal processing circuit respectively to obtain four subdivided signals, zero crossing points of the four subdivided signals are detected to generate two orthogonal pulse signals, pulses of the two orthogonal pulse signals are counted respectively and the phase differences of the two orthogonal pulse signals are detected respectively. According to the invention, based on the magnetic field information of the planar motor, the magnetic field space tau is subdivided to realize the long-travel high-accuracy rotor displacement of the planar motor. Through adoption of the device and method disclosed by the invention, the problems caused by the requirements of long travel and high accuracy that calculation methods are complicated or hardware is inconvenient to install and the total cost of a measurement device is high can be solved.

Description

technical field [0001] The invention relates to a mover displacement measuring device and method of a planar motor with a sinusoidal magnetic field model, in particular to a subdivision displacement measuring device and an algorithm with a large stroke and high resolution. Background technique [0002] In two-dimensional positioning processing devices, especially modern semiconductor micro-processing equipment and other ultra-precision processing equipment, high-precision motion is usually realized by planar motors. Due to the advantages of fast response, high sensitivity and simple structure, planar motors have attracted extensive attention in both academia and industry. Patent 201110045692.8, patent 200910029368.X, and patent 200910088894.3 describe several planar motors with different structures in detail. [0003] At present, optical measurement methods such as gratings and laser interferometers are often used to detect the position of the mover of planar motors. In pa...

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Problems solved by technology

In patent 200880111964.6, two-dimensional gratings are used to measure the motion of planar motors. It is necessary to install a larger area of ​​planar gratings on the planar motors to generate optical signals with displacement information for communication with optical sensors. The scale surface is polluted; patent 201110040403.5 uses a grating sensor to detect the movement position in two directions, and each movement direction needs to install a main scale that meets the range requirements and a corresponding reading head to generate moiré fringe signals or other types with displacement information The optical signal has high requirements for the use environment; the patent 200910029828.9 uses a laser position sensor to realize the motion measurement of the planar motor through the principle of laser triangulation or echo analysis. The measurement accuracy is greatly affected by the environment. Handling is difficult while keeping it simple and fast

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