Magnetic odometer with direction indicator systems and method

• US 7,928,724 B2
• Filed: 05/27/2008
• Issued: 04/19/2011
• Est. Priority Date: 05/27/2008
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Fang, Ron, Judd, Tom, Graham, Bruce, Vu, Toan
• Primary Examiner(s): WHITTINGTON, KENNETH
• Application Number:
  US12/127,691
• Publication Number:
  US 20090295376A1
• Time in Patent Office: 1,057 Days
• Field of Search: 324/207.24, 324/207.25, 324/160, 324/166, 324/173, 324/174, 324/178, 324/179, 735/143.9, 384/448
• 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 a vehicle, the system comprising:

a first set of magnets mounted to the vehicle, wherein the first set of magnets has at least one magnet with a north pole and a south pole;

a second set of magnets mounted to the vehicle, wherein the second set of magnets has at least one magnet with a north pole and a south pole;

a first magnetic sensor configured to produce a signal indicating a presence of a magnetic field produced by the first set of magnets;

a second magnetic sensor configured to produce a signal indicating a presence of a magnetic field produced by the second set of magnets; and

a processing device in signal communication with the first and second magnetic sensors, the processing device configured to determine a direction of motion of the object based on the produced signal, wherein the determined direction is a heading not limited to forward or reverse.

2. The system of claim 1, wherein the first and second magnetic sensors are 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 vehicle is a wheeled vehicle, the first set of magnets is mounted to a first wheel and the second set of magnets is mounted to a second wheel, such that the north poles and the south poles of the first and second sets of magets are approximately equidistant from a rotational axis of the first and second wheels, and the processing device is configured to determine a rotational direction of the first and second wheels.

8. The system of claim 7, wherein the first and second sets of magnets include a plurality of magnets mounted to the first and second wheels 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;

a second wheel rotationally coupled to the chassis;

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

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

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

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

a processing device in signal communication with the first single magnetic sensor and the second single magnetic sensor, the processing device configured to determine a first rotational direction of the first wheel and a second rotational direction of the second wheel and a corresponding direction of the wheeled vehicle based on the first and second produced signals, wherein the corresponding direction of the wheeled vehicle is a heading not limited to forward or reverse.

10. The system of claim 9, wherein the first and second magnetic sensors are 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 first rotational direction of the first wheel, the second rotational direction of the second wheel, and a corresponding direction of the wheeled vehicle based on a configuration of a first signal doublet and a second signal doublet, wherein the first and second signal doublets include the first and second characteristic signals.

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

12. The system of claim 11, 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.

13. The system of claim 12, 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.

14. A method for determining a direction of a vehicle, the method comprising:

sensing a first pole of a first magnet mounted on the vehicle 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;

sensing a first pole of a second magnet mounted on 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; and

determining a direction of the object based on an order in which the first and second poles of the first and second magnets are sensed, wherein the determined direction is a heading not limited to forward or reverse.

15. The method of claim 14, further comprising:

determining a displacement of the vehicle based on a doublet that includes the sensed first and second poles of the first and second magnets.

16. The method of claim 15, further comprising determining a position of the vehicle based on an initial position, the determined direction of the vehicle, and the determined displacement of the vehicle.

17. The method of claim 14, wherein the vehicle is a wheeled vehicle having a chassis and a first wheel rotationally coupled to the chassis, a second wheel rotationally coupled to the chassis, and wherein the first magnet is mounted on the first wheel of the vehicle, the second magnet is mounted on the second wheel of the vehicle, and wherein determining the direction comprises determining a first rotational displacement of the first wheel based on signals from the first magnetic sensor and determining a second rotational displacement of the second wheel based on signals from the second magnetic sensor.

18. The method of claim 17, further comprising:

determining a displacement of the vehicle based on the first and second 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.