Inductive sensor apparatus and method for deploying

• US 20030016005A1
• Filed: 06/28/2002
• Published: 01/23/2003
• Est. Priority Date: 06/29/2001
• Status: Active Grant

• Current Assignee: Inductive Signature Technologies Incorporated
• Original Assignee: Inductive Signature Technologies Incorporated
• Inventors: Leibowitz, Lawrence P., Hilliard, Steven R.
• Granted Patent: US 6,771,064 B2
• Time in Patent Office: Days
• US Class Current: 324/207.15
• CPC Class Codes: G08G 1/042 using inductive or magnetic detectors

Abstract

An apparatus for sensing variations in an inductive field, or inductive sensor. The inductive sensor is adapted for detecting the lateral offset of a vehicle within a roadway, especially those with multiple traffic lanes, without regard to lane boundaries, which may vary. Lateral offset information is necessary for determining lane usage statistics and is useful in detecting unsafe driving behaviors evidenced by erratic variations in lane position. Such unsafe driving behaviors are indicative of, for example, intoxicated or drowsy drivers, obstacles in the roadway requiring drastic avoidance measures, aggressive driving and other generally unsafe roadway conditions. In addition, lane position information can be passed back to the vehicle to allow for automated lane-keeping or passed to other detectors for self-calibration of the system.

Claims

1. An inductive sensor for use in a roadway having a surface, said inductive sensor comprising:

a first wire-loop defining a first end, a second end and a longitudinal axis that is substantially parallel to the roadway surface, said first-wire loop having a first leg and a second leg that are symmetrically disposed in relation to said longitudinal axis, an end of said first leg being in electrical communication with a proximate end of said second leg, said first wire-loop second end being offset from said first wire-loop first end by a selected angular offset.

2. The inductive sensor of claim 1 wherein said first leg and said second leg are substantially equidistant from said longitudinal axis.

3. The inductive sensor of claim 1 wherein said first leg and said second leg are helically wound around said longitudinal axis.

4. The inductive sensor of claim 1 further comprising a second wire-loop defining a longitudinal axis, said second wire-loop having a first leg and a second leg that are substantially equidistant, helically wound around, and symmetrically disposed in relation to said longitudinal axis, said second wire-loop offset from said first wire-loop by approximately ninety degrees.

5. The inductive sensor of claim 1 further comprising a loop-forming member upon which said first wire-loop is disposed.

6. The inductive sensor of claim 5 wherein said loop-forming member is a cylindrical form.

7. The inductive sensor of claim 1 further comprising an inductance measurement circuit in electrical communication with said first wire-loop.

8. The inductive sensor of claim 1 wherein said angular offset is approximately ninety degrees over a selected length.

9. An inductive sensor for use in a roadway having a surface and width, said inductive sensor comprising:

a first wire-loop and a second wire-loop, each of said first wire-loop and said second wire-loop defining a longitudinal axis that is substantially parallel to the roadway surface and a pair of longitudinal legs, each said pair of longitudinal legs helically wound around said longitudinal axis, said first wire-loop being radially offset from said second wire-loop by a predetermined angular offset.

10. An inductive sensor for use in a roadway defining a surface, said inductive sensor comprising:

a first wire-loop and a second wire-loop each defining at least three legs, one of said at least three legs of each of said first wire-loop and said second wire-loop being internal to a generally planar quadrilateral defined by the remaining of said at least three legs of each of said first wire-loop and said second wire-loop, said internal legs abutting one another and intersecting said longitudinal axis at a selected point.

11. The inductive sensor of claim 10 wherein said internal legs bisect said longitudinal axis.

12. The inductive sensor of claim 10 wherein each of said first wire-loop and said second wire-loop lie in a plane substantially perpendicular to said roadway surface.

13. The inductive sensor of claim 10 wherein each of said first wire-loop and said second wire-loop lie in a plane substantially parallel to said roadway surface.

15. The inductive sensor of claim 14 wherein each of said first wire-loop and said second wire-loop lie in a plane substantially perpendicular to said roadway surface.

16. The inductive sensor of claim 14 wherein each of said first wire-loop and said second wire-loop lie in a plane substantially parallel to said roadway surface.

19. The inductive sensor of claim 18 wherein each of said primary wire-loop and said secondary wire-loop lie in a plane substantially perpendicular to said roadway surface.

20. The inductive sensor of claim 18 wherein each of said primary wire-loop and said secondary wire-loop lie in a plane substantially parallel to said roadway surface.

21. The inductive sensor of claim 18 wherein said first of said pair of longitudinal legs of each of said primary wire-loop and said secondary wire-loop and all of said at least one lateral legs of said primary wire-loop and said secondary wire-loop define a perimeter of a quadrilateral.

14. An inductive sensor for use in a roadway defining a surface, said inductive sensor comprising:

a first wire-loop and a second wire-loop geometrically arranged to form a quadrilateral, said quadrilateral enclosing an inner leg of each of said first wire-loop and said second wire-loop, said first wire-loop inner leg abutting said second wire-loop inner leg, said first wire-loop inner leg and said second wire-loop inner leg dividing said quadrilateral into said two segments of substantially equal area.

17. An inductive sensor for use in a roadway defining a surface and a direction of vehicular travel, said inductive sensor comprising:

a primary wire-loop defining a pair of longitudinal segments, a first lateral segment, and a second lateral segment, said first lateral segment and said second lateral segment being substantially parallel to the direction of vehicular travel, said first lateral segment and said second lateral segment being of unequal length; and

a secondary wire-loop defining a pair of longitudinal segments, a first lateral segment, and a second lateral segment, said first lateral segment and said second lateral segment being substantially parallel to the direction of vehicular travel, said first lateral segment and said second lateral segment being of unequal length, said primary wire-loop first lateral segment and said secondary wire-loop second lateral segment being substantially equal in length, said primary wire-loop second lateral segment and said secondary wire-loop second lateral segment being substantially equal in length.

18. An inductive sensor for use in a roadway defining a surface and a direction of vehicular travel, said inductive sensor comprising:

a primary wire-loop defining a pair of longitudinal legs and at least one lateral leg, said at least one primary wire-loop lateral leg being substantially parallel to the direction of vehicular travel, a first of said pair of longitudinal legs electrically connected to an end of first said at least one lateral leg, a second of said pair of longitudinal legs electrically connected to an opposing end of said at least one lateral leg; and

a secondary wire-loop defining a pair of longitudinal legs and at least one lateral leg, said at least one secondary wire-loop lateral leg being substantially parallel to the direction of vehicular travel, a first of said pair of longitudinal legs electrically connected to an end of first said at least one lateral leg, a second of said pair of longitudinal legs electrically connected to an opposing end of said at least one lateral leg, wherein said secondary wire-loop at least one lateral leg and said primary wire-loop at least one lateral leg are substantially equal in length.

22. An inductive sensor for use in a roadway defining a surface and a direction of vehicular travel, said inductive sensor comprising:

a primary wire-loop defining a pair of longitudinal legs and at least one lateral leg, each of said pair of longitudinal legs and said at least one lateral leg having a first and an opposing second end, said at least one lateral leg being substantially parallel to the direction of vehicular travel, a first end of a first said pair of longitudinal legs connected to a first end of a first said at least one lateral leg, a first end of a second of said pair of longitudinal legs connected to an opposing end of said first lateral leg, said second ends of said pair of longitudinal legs being in electrical communication; and

a secondary wire-loop defining a pair of longitudinal legs and at least one lateral leg, said at least one lateral leg being substantially parallel to the direction of vehicular travel, a first of said pair of longitudinal legs connected to a first end of a first said at least one lateral leg, a second of said pair of longitudinal legs connected to an opposing end of said first lateral leg, said second ends of said pair of longitudinal legs being in electrical communication, wherein a distance between said primary wire-loop pair of longitudinal legs second ends is substantially equal to a distance between said secondary wire-loop pair of longitudinal legs second ends.

23. The inductive sensor of claim 22 wherein said second ends of each said pair of longitudinal legs are electrically connected by a second at least one lateral leg.

24. The inductive sensor of claim 22 wherein said second ends of each said pair of longitudinal legs are directly connected.

25. The inductive sensor of claim 22 wherein each of said primary wire-loop and said secondary wire-loop lie in a plane substantially perpendicular to said roadway surface.

26. The inductive sensor of claim 22 wherein each of said primary wire-loop and said secondary wire-loop lie in a plane substantially parallel to said roadway surface.

27. The inductive sensor of claim 22 wherein said first of said pair of longitudinal legs of each of said primary wire-loop and said secondary wire-loop and all of said at least one lateral legs of said primary wire-loop and said secondary wire-loop define a perimeter of a quadrilateral.

29. The inductive sensor of claim 28 where said maximum depth is approximately one centimeter.

30. The inductive sensor of claim 28 where said maximum depth is approximately one inch.

28. An inductive sensor for use in a roadway having a surface, said inductive sensor comprising:

a plurality of interconnected grooves being cut into said roadway surface to a maximum depth; and

a conductive filler material disposed within said plurality of interconnected grooves.

31. An inductive sensor for use in a roadway having a surface, said inductive sensor comprising:

a conductive material applied to the roadway surface without channeling the roadway surface, said conductive material configured as a loop.

32. A method for embedding an inductive sensor in a roadway surface, said method comprising:

grooving the roadway surface to a selected maximum depth to produce a channel; and

filling said channel with a conductive material to form a loop.

33. The method of claim 32 where said maximum depth is approximately one inch.

34. The method of claim 32 where said maximum depth is approximately one centimeter.

35. A method for installing an inductive sensor on a roadway surface, said method comprising:

applying a conductive material to the roadway surface without channeling the roadway surface; and

forming a loop from said conductive material.

36. An inductive sensor for use in a roadway having a surface, said inductive sensor comprising:

at least one wire-loop oriented substantially perpendicular to the roadway surface, said at least one wire-loop defining a first horizontal leg parallel a second horizontal leg;

said first horizontal leg being separated from said second horizontal leg by a distance of not more than three feet.

37. An inductive sensor for use in a roadway having a surface, said inductive sensor comprising:

at least one wire-loop oriented substantially perpendicular to the roadway surface, said at least one wire-loop having not more than two hundred turns.

38. An inductive sensor for use in a roadway having a surface, said inductive sensor comprising:

at least one wire-loop oriented substantially parallel to the roadway surface, said at least one wire-loop defining a first longitudinal leg parallel a second longitudinal leg;

said first longitudinal leg being separated from said second longitudinal leg by a distance of not more than fifteen centimeters.