METHOD OF LOCATING THE POSITION OF LINEAR OBJECTS

• US 20140312904A1
• Filed: 04/22/2014
• Published: 10/23/2014
• Est. Priority Date: 04/23/2013
• Status: Active Grant

• Current Assignee: Takachiho Sangyo Co., Ltd.
• Original Assignee: Takachiho Sangyo Co., Ltd.
• Inventors: MIZUNO, Morio
• Granted Patent: US 9,664,810 B2
• Time in Patent Office: Days
• US Class Current: 324/326
• CPC Class Codes: G01V 3/104 using several coupled or uncoupled coils G01V3/101 takes precedence

Abstract

A method of locating a position of a linear object, including arranging a first and a second reactor around a measuring point, the first reactor generating an induced voltage corresponding to an X-direction component of a magnetic field, the X direction perpendicular to a running direction of the object, and the second reactor generating an induced voltage corresponding to a Y-direction component of the field, the Y direction perpendicular to the X-direction and the running direction; obtaining a first reactor induced voltage and a second reactor induced voltage; setting an X-distance as a first distance from the point to the object center, and setting the Y-distance as a second distance; and estimating a direction in which the linear object is located as viewed from the point, by regarding an X-distance to Y-distance ratio as equal to a ratio of the first voltage to the second voltage multiplied by a coefficient.

Claims

1. A method of locating the position of a linear object on the basis of an alternating field located at a measuring point spaced away from the linear object, wherein a miming direction of the linear object is known, and an alternating field is generated in the circumference, the method comprising:

arranging a first and a second reactor around the measuring point, the first reactor generating an induced voltage corresponding to an X-direction component of a magnetic field, the X direction being perpendicular to the running direction of the linear object, and the second reactor generating an induced voltage corresponding to a Y-direction component of the magnetic field, the Y direction being perpendicular both to the X-direction component and to the running direction of the linear object;

obtaining a first reactor voltage induced by the alternating field in the first reactor and a second reactor voltage induced by the alternating field in the second reactor;

setting an X-distance as a first distance from the measurement point to a center of the linear object, and setting the Y-distance as a second distance from the measurement point to the center of the linear object; and

estimating a direction in which the linear object is located as viewed from the measurement point, by regarding a ratio of the X-distance to the Y-distance as equal to a ratio of the first reactor voltage to the second reactor voltage multiplied by a certain coefficient.

2. The method of locating the position of a linear object according to claim 1,

wherein the first reactor comprises a first coil and a second coil that are differentially connected, spaced apart from each other, and arranged on opposite sides of the measurement point in the X-direction, and

wherein the second reactor comprises a third coil and a fourth coil differentially connected, spaced apart from each other, and arranged on opposite sides of the measurement point in the Y-direction.

3. The method of locating the position of a linear object according to claim 2,

wherein the step of estimating the direction includes removing an error in proportion to the X-distance from the ratio of the first reactor voltage to the second reactor voltage.

4. The method of locating the position of a linear object according to claim 2, further comprising:

obtaining a third coil voltage induced in the third coil by the alternating field, and a fourth coil voltage induced in the fourth coil by the alternating field;

calculating the Y-distance based on the third and fourth coil voltages while assuming the X-distance as zero; and

correcting the calculated Y-distance based on the ratio of the first reactor voltage to the second reactor voltage.

5. The method of locating the position of a linear object according to claim 4, further comprising

calculating the X-distance based on the corrected Y-distance and the ratio of the first reactor voltage to the second reactor voltage.