US 12,085,420 B2
Angle measurement system based on magnetic method and measurement method therefor
Je Kook Kim, Seoul (KR); Kyoung Soo Kwon, Gwacheon-si (KR); Chae Dong Go, Hwaseong-si (KR); and Suk Jung Lee, Yongin-si (KR)
Assigned to SNA CO., LTD., Yongin-si (KR)
Filed by SNA Co., Ltd., Yongin-si (KR)
Filed on Oct. 17, 2022, as Appl. No. 17/967,377.
Claims priority of application No. 10-2021-0150355 (KR), filed on Nov. 4, 2021; and application No. 10-2022-0067951 (KR), filed on Jun. 3, 2022.
Prior Publication US 2023/0140330 A1, May 4, 2023
Int. Cl. G01D 5/14 (2006.01)
CPC G01D 5/145 (2013.01) 10 Claims
OG exemplary drawing
 
1. An angle measurement system configured to use a magnet and provided with a first track and a second track, the angle measurement system comprising:
an absolute angle calculation unit configured to calculate an absolute angle of a position of the magnet by using a 1-1th digital signal obtained by measuring a magnetic field signal of the first track and converted into a digital signal, a 1-2th digital signal obtained by measuring the magnetic field signal of the first track and converted into a digital signal, a 2-1th digital signal obtained by measuring a magnetic field signal of the second track and converted into a digital signal, and a 2-2th digital signal obtained by measuring the magnetic field signal of the second track and converted into a digital signal,
wherein the 1-1th digital signal and the 1-2th digital signal are sinusoidal signals having a phase difference of 90 degrees from each other, and the 2-1th digital signal and the 2-2th digital signal are sinusoidal signals having a phase difference of 90 degrees from each other, and
wherein an absolute angle of the position of the magnet is configured to comprise at least one piece of data comprising:
main section values obtained by dividing one rotation of 360 degrees of the magnet into a first main section to a fourth main section, which are four 90 degree sections;
sub-section values obtained by dividing each of the first main section to the fourth main section into a plurality of sections by a value using the phase difference between the magnetic field signal of the first track and the magnetic field signal of the second track;
first signal section values obtained by dividing the magnetic field signal of the first track into four first signal sections by using a sign of the 1-1th digital signal and a sign of the 1-2th digital signal; and
lower section values calculated by the 1-1th digital signal and the 1-2th digital signal for each first signal section value.