PLANAR MOTOR ROTOR DISPLACEMENT MEASURING DEVICE AND ITS MEASURING METHOD

摘要

A planar motor rotor displacement measuring device and its measuring method are provided. The motor is a moving-coil type planar motor. The device comprises probes, two sets of sine sensors, two sets of cosine sensors, a signal lead wire and a signal processing circuit. The method is arranging two sets of magnetic flux density sensors within a magnetic field pitch τ along two vertical movement directions in the rotor located in the sine magnetic field area. Sampled signals of the four sets of sensors are respectively processed with a frequency multiplication operation, four subdivision signals are obtained, the zero-crossing points of the four subdivision signals are detected, and then two sets of orthogonal pulse signals are generated. The pulse number of the orthogonal pulse signals is counted, and phase difference of the two sets of orthogonal pulse signals is respectively detected.

主权项

1. A planar motor rotor displacement measuring device, wherein the planar motor is a moving-coil type planar motor comprising a stator (1) and a rotor (3) on the stator (1), the stator (1) includes a magnetic steel array (2), and a coil array (4) is arranged on the lower surface of the rotor (3), characterized in that,
the displacement measuring device comprises a probe (5), two sets of sine sensors, two sets of cosine sensors, a signal lead wire (6) and a signal processing circuit (7); the probe (5) is arranged at the edge of the rotor (3) which is located in the sine magnetic field area generated by the magnetic steel array of the stator of the moving-coil type planar motor ; the two sets of sine sensors include an x-direction sine sensor set (8) and a y-direction sine sensor set (10), the two sets of cosine sensors include an x-direction cosine sensor set (9) and a y-direction cosine sensor set (11); the sensors are arranged in the probe (5) in such a manner, firstly, a sensor is arranged in the probe (5) as the reference sensor (12), my sensors in total including the reference sensor (12) are uniformly arranged within one magnetic field pitch τ along the x-direction, forming the y-direction sine sensor set; taking the reference sensor (12) as the first sensor, mx sensors in total including the reference sensor (12) are uniformly arranged within one magnetic field pitch τ along the y-direction, forming the x-direction sine sensor set; beginning at the distance of τ/4 from the reference sensor (12) in the y-direction, my sensors are uniformly arranged within one magnetic field pitch τ along the x-direction, forming the y-direction cosine sensor set; beginning at the distance of τ/4 from the reference sensor (12) in the x-direction, mx sensors are uniformly arranged within one magnetic field pitch τ along the y-direction, forming the x-direction cosine sensor set, where mx=2,3,4, . . . , my=2,3,4, . . . ; the signal processing circuit (7) is connected with the output of the probe (5) via the signal lead wire (6); the signal processing circuit (7) includes an analog signal processing unit and a digital signal processing unit; and the magnetic field pitch τ is the spatial period of the sine magnetic field of the planar motor.