A New Kind of Absolute Magnetic Encoder

Abstract

To fulfill the requirement of fields such as robotics, aviation, and special machining, motors with quill shafts or outer rotors have been used. For these special motors, the photoelectric encoder’s volume is normally too big and easy to be polluted by oil or dust; magnetic encoder normally has poor accuracy, and alnico piece may not provide enough magnetic field coverage area. The aim of this essay is to find a new structure of magnetic encoder to improve the precision and magnetic field coverage area. By using two multi-pole alnico rings with a different number of pole pairs to provide a magnetic field, the coverage area could be improved. The position differences between two alnicos pole positions are used to calculate absolute angle value, so the accuracy of the encoder could be absolute and no less than that of a combined magnetic encoder with the same number of pole pairs. A special algorithm is proposed for decoding. This new kind of magnetic encoder could be used on special motors with quill shafts or outer rotors. Its volume and weight are less than the photoelectric encoder and have better performance on antipollution. The alnico ring is easy to modify to suit the structure of the motor.

A review of indoor-orbital electrical inspection robots in substations

“…The feedback control system of the track-type automatic inspection robot consisted of an industrial computer, six DC servo motors with incremental photoelectric encoders (Li et al , 2014) and absolute magnetic encoders (Feng et al , 2021), and one control panel composition. RS 485 was used as a communication standard to connect between the PC and motion controller.…”

“…The rail-type inspection robot used in substations was equipped with radio frequency identification (RFID) (Navarro et al, 2015;Tang et al, 2020) on the side of the orbit to obtain the absolute position and incremental position, which was regarded as a simple and convenient positioning method. The proximity switch was installed on the top of the vertical lifting mechanism to act as a zero limited location, and the position of the DC servo motor was determined by the comprehensive preset integrated cloud platform in the vertical direction, as shown in Figure 9 and absolute magnetic encoders (Feng et al, 2021), and one control panel composition. RS 485 was used as a communication standard to connect between the PC and motion controller.…”

Novel High Accuracy Resolver Topology for Space Applications

“…These type of encoders offer lower accuracies than the optical ones. However, they are smaller, cheaper, and more robust to harsh environments [ 22 ].…”

Design of a miniaturized optical system for machine vision angular displacement sensors

“…Among them, photoelectric angular displacement sensors have become the main development direction of angular displacement sensors due to their high precision, non-contact, and small external influence. Optoelectronic angular displacement sensors can be further divided into types such as Moire fringes and encoding [3][4][5][6] . The Moire fringe type angular displacement sensor detects angle changes by detecting the motion of Moire fringes between grating pairs.…”