A Novel Angle Segmentation Method for Magnetic Encoders Based on Filtering Window Adaptive Adjustment Using Improved Particle Swarm Optimization

Abstract

In this paper we outline newly-developed control algorithms, designed to achieve high-precision feedback for a motor control system using a magnetic encoder. The magnetic encoder, combing single-pole and multi-pole magnetic steels, was adopted to extend the resolution of the magnetic encoder. First, with a view to settling the issue of the jump points of the multi-pole angle value at the convergence of two adjacent magnetic poles, the angle segmentation method, which uses the window filter discrimination method, is employed to determine the actual angle value. The appropriate filter window width is selected via the improved particle swarm optimization (IPSO) algorithm, and an expanded resolution is achieved. Second, a compensation table is completed via a linear compensation algorithm based on virtual cutting to enhance the accuracy of the combined magnetic encoder. On this basis, a linear difference algorithm is used to achieve deviation correction of the angle. Finally, the jump points can be restrained effectively via the angle segmentation method. The resolution reaches 0.05°, and the accuracy is 0.045°.

Research on high-precision encoder based on optical-magnetic combination structure to measure absolute angle

“…There is no time delay in solving for angles. [19] Window Filtering Method The method proposed in this paper is more accurate. Suitable for solving the angle of various encoders with different pole pairs.…”

“…It is difficult to calculate the absolute angle of the current moment because the specific interval number of the current moment can not be determined only by a multi-pole magnetic ring. Therefore, some scholars have proposed an encoder that combines single pole and multi-pole magnetic ring [15], collects the angles of single-pole and multi-pole at the same time, uses the angles of single-pole to judge the interval of multi-pole, and calculates the absolute angle by combining the angles of multi-pole. Alternatively, two multi-pole magnetic rings are combined [16], and the position difference between the two magnetic poles is used to find the final absolute angle value.…”