Object locater and method for locating a metallic and/or magnetizable object

Patent metadata

Field	Value
Publication number	US-10054709-B2
Application number	US-201414782152-A
Country	US
Kind code	B2
Filing date	Feb 14, 2014
Priority date	Apr 4, 2013
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A sensor for locating metallic or magnetizable objects comprises two emission coils and a receiving coil which are inductively interconnected. A method for determining the influence of temperature on the sensor includes supplying a first pair of predetermined alternating currents to the emitter coils, and simultaneously sampling current flows which pass through the emitter coils and a first current of the receiver coil. Subsequently, the method includes supplying a second pair of predetermined alternating currents to the emitter coils, and simultaneously sampling current flows which pass through the emitter coils and a second current of the receiver coil. The method further includes determining coupling factors between the emitter coils and the receiver coils based on the determined current flows and voltages, and determining the object based on the coupling factors.

First claim

The invention claimed is:

1. A method for locating an object that is at least one of metallic and magnetic with a sensor including two transmitting coils and a receiving coil which are inductively coupled to each other, the method comprising:
supplying a first pair of predetermined AC voltages to the two transmitting coils;
sampling first currents flowing through the two transmitting coils and a first voltage of the receiving coil while the first pair of predetermined AC voltages are supplied;
supplying a second pair of predetermined AC voltages to the two transmitting coils;
sampling second currents flowing through the two transmitting coils and a second voltage of the receiving coil while the second pair of predetermined AC voltages are supplied;
determining, with a processor, coupling factors between the two transmitting coils and the receiving coil based on (i) the sampled first currents through the two transmitting coils, (ii) the sampled second currents through the two transmitting coils, (iii) the sampled first voltage of the receiving coil, and (iv) the sampled second voltage of the receiving coil; and
detecting, with the processor, the object based on the coupling factors.

2. The method as claimed in claim 1 , further comprising:
detecting, with the processor, the object if the coupling factors differ with respect to coupling factors of a previous measurement.

3. The method as claimed in claim 2 , wherein previously sampled voltages of the receiving coil of the previous measurement and the coupling factors of the previous measurement relate to an arrangement in which the inductive coupling between the two transmitting coils and the receiving coil is not influenced by metallic or magnetizable objects.

4. The method as claimed in claim 1 , further comprising:
phase-shifting the first pair of predetermined AC voltages with respect to each other by less than ±5°; and
phase-shafting the second pair of predetermined AC voltages with respect to each other by less than ±5°.

5. The method as claimed in claim 1 , further comprising:
choosing constants A, B, C1, and C2 such that the following statements are valid:
a voltage of a first transmitting coil of the two transmitting coils for the first pair of predetermined AC voltages is equal to A;
a voltage of a second transmitting coil of the two transmitting coils for the first pair of predetermined AC voltages is equal to B plus C1;
a voltage of the first transmitting coil for the second pair of predetermined AC voltages is equal to A plus C2;
a voltage of the second transmitting coil for the second pair of predetermined AC voltages is equal to B;
A divided by B is equal to a second coupling factor of the coupling factors that corresponds to the second transmitting coil divided by a first coupling factor of the coupling factors that corresponds to the first transmitting coil;
C1 is approximately 3% to 7% of A; and
C2 is approximately 3% to 7% of B.

6. The method as claimed in claim 1 , further comprising:
determining the coupling factors and offsetting the coupling factors against each other a first time; and
determining the coupling factors and offsetting the coupling factors against each other a second time after reversing a polarity of the receiving coil.

7. The method as claimed in claim 1 , wherein a computer program product includes program code configured to carry out the method if the computer program product runs on a processing device or is stored on a computer-readable data carrier.

8. A sensor for locating an object that is at least one of metallic and magnetic, comprising:
two transmitting coils;
a receiving coil, the two transmitting coils and the receiving coil inductively coupled to each other;
a control device configured to supply the two transmitting coils with AC voltages;
a sampling device configured to sample currents flowing through the two transmitting coils and to sample a received signal from the receiving coil;
a processing device configured to determine coupling factors between the two transmitting coils and the receiving coil based on the sampled currents and the sampled received signal, the processing device further configured to detect the object based on the coupling factors.

9. The sensor as claimed in claim 8 , wherein:
the sampling device comprises an analog-digital converter and a selection device configured to alternatively sample the received signal from the receiving coil or one of the currents flowing through the two transmitting coils.

10. The sensor as claimed in claim 8 , further comprising:
a selection device configured to reverse a polarity of the receiving coil.

11. The sensor as claimed in claim 8 , wherein the control device comprises a digital-analog converter.

12. The sensor as claimed in claim 8 , further comprising:
a first reference voltage source configured to supply the receiving coil with a predetermined voltage.

13. The sensor as claimed in claim 12 , further comprising:
a second reference voltage source configured to supply each of the transmitting coils with a predetermined voltage.

14. A measuring device for detecting objects enclosed in a medium, comprising:
at least one sensor including (i) two transmitting coils, (ii) a receiving coil, the two transmitting coils and the receiving coil inductively coupled to each other, (iii) a control device configured to supply the two transmitting coils with AC voltages, (iv) a sampling device configured to sample currents flowing through the two transmitting coils and to sample a received signal from the receiving coil, and (v) a processing device configured to determine coupling factors between the two transmitting coils and the receiving coil based on the sampled currents and the sampled received signal, the processing device further configured to detect the object based on the coupling factors.

Assignees

• Bosch Gmbh Robert

Inventors

• Hahl Markus
• Winterhalter Juergen
• Albrecht Andrej
• Zibold Tobias
• Grossmann Oliver

Classifications

• G01V3/104 Primary

  using several coupled or uncoupled coils (G01V3/101 takes precedence) · CPC title