MAGNETIC ODOMETER WITH DIRECTION INDICATOR SYSTEMS AND METHODS

• US 20090295376A1
• Filed: 05/27/2008
• Published: 12/03/2009
• Est. Priority Date: 05/27/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Judd, Tom, Graham, Bruce, Vu, Toan, Fang, Ron
• Granted Patent: US 7,928,724 B2
• Time in Patent Office: Days
• US Class Current: 324/207.23
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01C 22/00 Measuring distance traversed on the ground by vehicles, persons, animals or other moving solid bodies, e.g. using odometers, using pedometers
• CPC Class Codes: G01P 13/04 Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement

Abstract

Systems and methods for determining a directional movement of an object such as a wheeled vehicle. The system includes a magnet having a north pole and a south pole mounted to the object, a single magnetic sensor positioned such that the sensor can individually detect each magnetic pole as the object moves, the sensor configured to produce a first characteristic signal when a north pole is detected and a second characteristic signal when a south pole is detected, and a processing device in signal communication with the sensor, the processing device configured to determine a directional movement of the object based on a configuration of a signal doublet that includes the first and second characteristic signals. The methods include sensing the north and south poles as they pass the magnetic sensor and determining a direction based on an order in which the north and south poles are sensed.

Claims

1. A system for determining a directional movement of an object, the system comprising:

at least one magnet having a north pole and a south pole mounted to the object;

a single magnetic sensor configured to produce a signal indicating a presence of a magnetic field produced by the north or south pole of the at least one magnet; and

a processing device in signal communication with the magnetic sensor, the processing device configured to determine a direction of motion of the object based on the produced signal.

2. The system of claim 1, wherein the magnetic sensor is configured to produce a predetermined first characteristic signal when a north pole is detected and a predetermined second characteristic signal when a south pole is detected, and wherein the processing device is configured to determine the direction of motion based on a configuration of a signal doublet, wherein the signal doublet includes the first and second characteristic signals.

3. The system of claim 2, wherein the first characteristic signal includes a first voltage and the second characteristic signal includes a second voltage, wherein the first and second voltages are not equal.

4. The system of claim 2, wherein the processing device is configured to determine a direction based on whether the first or second characteristic signal appears first in the signal doublet.

5. The system of claim 2, wherein the processing device is further configured to determine a displacement of the object during a predetermined time period based on signals received from the magnetic sensor.

6. The system of claim 5, wherein the processing device is further configured to determine a position of the object based on an initial position of the object, the determined direction of the object, and the determined displacement of the object.

7. The system of claim 2, wherein the object is a wheel, the at least one magnet is mounted to the wheel such that the north pole and the south pole are approximately equidistant from a rotational axis of the wheel, and the processing device is configured to determine a rotational direction of the wheel.

8. The system of claim 7, wherein the at least one magnet includes a plurality of magnets mounted to the wheel such that the north and south poles of all of the plurality of magnets are oriented in a similar fashion.

9. A system for determining a direction of a wheeled vehicle, the system comprising:

a chassis;

a first wheel rotationally coupled to the chassis;

at least one magnet having a north pole and a south pole mounted to the first wheel of the wheeled vehicle;

a first single magnetic sensor configured to produce a signal indicating a presence of a magnetic field produced by the north or south pole of the at least one magnet; and

a processing device in signal communication with the first single magnetic sensor, the processing device configured to determine a rotational direction of the first wheel and a corresponding direction of the wheeled vehicle based on the produced signal.

10. The system of claim 9, wherein the first magnetic sensor is configured to produce a predetermined first characteristic signal when a north pole is detected and a predetermined second characteristic signal when a south pole is detected, and wherein the processing device is configured to determine a rotational direction of the first wheel and a corresponding direction of the wheeled vehicle selected from forward or reverse based on a configuration of a first signal doublet, wherein the first signal doublet includes the first and second characteristic signals from the first magnetic sensor.

11. The system of claim 10, wherein the processing device is configured to determine the rotational direction of the first wheel based on whether the first or second characteristic signal from the first magnetic sensor appears first in the first signal doublet.

12. The system of claim 10, further comprising:

a second wheel rotationally coupled to the chassis;

at least one magnet having a north pole and a south pole mounted to the second wheel of the wheeled vehicle; and

a second single magnetic sensor configured to produce a predetermined first characteristic signal when a north pole is detected and a predetermined second characteristic signal when a south pole is detected,

wherein the first and second wheels only turn axially and wherein the processing device is in signal communication with the second single magnetic sensor and is further configured to determine a rotational displacement of the first and second wheels based on signals received from the first and second magnetic sensors respectively, and wherein the processing device is further configured to determine a rotational direction of the second wheel based on a configuration of a second signal doublet, wherein the second signal doublet includes the first and second characteristic signals from the second magnetic sensor, and wherein the processor is further configured to determine a direction of the wheeled vehicle wherein the determined direction of the wheeled vehicle is a heading not limited to forward or reverse, the heading based on determined rotational directions and determined rotational displacements of the first and second wheels.

13. The system of claim 12, wherein the processing device is further configured to determine a displacement of the wheeled vehicle based on the determined direction of the wheeled vehicle and the determined rotational displacements of the first and second wheels during a predetermined time period.

14. The system of claim 13, wherein the processing device is further configured to determine a position of the vehicle based on an initial position, an initial heading, the determined displacement of the vehicle, and the determined direction of the vehicle.

15. A method for determining a direction of an object, the method comprising:

sensing a first pole of a first magnet mounted on the object as the first pole passes a first single magnetic sensor;

sensing a second pole of the first magnet as the second pole passes the first single magnetic sensor; and

determining a direction of the object selected from a first direction and a second direction opposite the first direction based on an order in which the first and second poles are sensed.

16. The method of claim 15, further comprising:

determining a displacement of the object during a predetermined period of time based on a doublet that includes the sensed first and second poles.

17. The method of claim 16, further comprising determining a position of the object based on an initial position, the determined direction of the object, and the determined displacement of the object.

18. The method of claim 15, wherein the object is a wheeled vehicle having a chassis and a first wheel rotationally coupled to the chassis, and wherein the first magnet is mounted on the first wheel of the vehicle and wherein determining the direction comprises determining whether the wheeled vehicle is moving in a forward or a reverse direction.

19. The method of claim 18, wherein the wheeled vehicle further includes a second wheel rotationally coupled to the chassis and the method further comprises:

sensing a first pole of a second magnet mounted on the second wheel of the vehicle as the first pole passes a second single magnetic sensor;

sensing a second pole of the second magnet as the second pole passes the second single magnetic sensor;

determining a direction of the second wheel selected from forward and reverse based on an order in which the north and south poles of the second magnet are sensed;

determining a rotational displacement of the first wheel based on signals from the first magnetic sensor; and

determining a rotational displacement of the second wheel based on signals from the second magnetic sensor;

wherein determining a direction of the vehicle is a heading not limited to forward or reverse, the heading based on the determined directions and the determined rotational displacements of the first and second wheels.

20. The method of claim 19, further comprising:

determining a displacement of the vehicle based on the determined rotational displacements of the first and second wheels; and

determining a position of the vehicle based on an initial position, the determined direction and the determined displacement of the vehicle.