STEER CORRECTION FOR A REMOTELY OPERATED MATERIALS HANDLING VEHICLE

• US 20110046813A1
• Filed: 12/30/2009
• Published: 02/24/2011
• Est. Priority Date: 08/18/2009
• Status: Active Grant

• Current Assignee: RingCentral Incorporated
• Original Assignee: RingCentral Incorporated
• Inventors: Schumacher, Mark E., McCroskey, William W., Schloemer, James F., Siefring, Vernon W., Castaneda, Anthony T., Wellman, Timothy A.
• Granted Patent: US 8,452,464 B2
• Time in Patent Office: Days
• US Class Current: 701/2
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: B66F 9/07568 Steering arrangements
• CPC Class Codes: B66F 9/07581 Remote controls
• CPC Class Codes: G05D 1/0033 by having the operator tracking the vehicle either by direct line of sight or via one or more cameras located remotely from the vehicle
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 2201/20 Binding and programming of remote control devices

Abstract

A materials handling vehicle automatically applies a steer correction maneuver if an object is detected in a steer bumper zone in front of the vehicle. A controller detects whether an object is in front of the materials handling vehicle and automatically determines whether a steer correction maneuver should be to the right or left of the traveling direction of the materials handling vehicle. The materials handling vehicle automatically steer corrects the vehicle, e.g., at a determined steer angle that is opposite the direction to the detected position of the object, and accumulates the distance traveled by vehicle while steer correction is being performed. The vehicle then automatically counter steers the vehicle, e.g., by a determined steer amount, in the opposite direction as the steer correction for a percentage of accumulated steer distance traveled. After performing the counter steer maneuver, the vehicle may, for example, resume a substantially straight heading.

Claims

1. A method of automatically applying a steer correction maneuver to a materials handling vehicle comprising:

receiving first sensor data from at least one remote sensing device, by a controller on a materials handling vehicle, where the first received sensor data defines a first steer bumper zone that is proximate to the materials handling vehicle;

receiving second sensor data from at least one remote sensing device, by the controller on the materials handling vehicle, where the second received sensor data defines a second steer bumper zone that is proximate to the materials handling vehicle;

detecting by the controller whether an object is in at least one of the first and second steer bumper zones based upon the received sensor data; and

performing a steer correction maneuver if the controller detects an object in one of the first or second steer bumper zones by;

determining by the controller, whether a steer correction maneuver should be to the right or to the left of the traveling direction of the materials handling vehicle based upon the received sensor data defining the first and second steer bumper zones;

performing a first steer correction maneuver if the controller determines that the object is to the left of the materials handling vehicle by;

automatically steer correcting the vehicle to the right by a determined correction amount;

accumulating the distance traveled by the materials handling vehicle while automatically steer correcting the vehicle to the right; and

automatically counter steering the materials handling vehicle to the left by a determined counter steer amount for a percentage of the accumulated steer distance traveled;

performing a second steer correction maneuver if the controller determines that the object is to the right of the materials handling vehicle by;

automatically steer correcting the vehicle to the left by the determined amount;

accumulating the distance traveled by the materials handling vehicle while automatically steer correcting the vehicle to the left; and

automatically counter steering the materials handling vehicle to the right by the determined counter steer amount for a percentage of the accumulated steer distance traveled.

2. The method according to claim 1, further comprising performing the steer correction maneuver while the materials handling vehicle is traveling in response to receiving a corresponding wirelessly transmitted travel request by a corresponding wireless transmitter.

3. The method according to claim 1, wherein receiving first sensor data from at least one remote sensing device and receiving second sensor data from at least one remote sensing device comprises:

receiving the first and second sensor data from a scanning laser device.

4. The method according to claim 3, wherein the scanning laser device has at least two outputs configured such that a first output designates whether an object is detected in the first steer bumper zone and a second signal designates whether an object is detected in the second steer bumper zone.

5. The method according to claim 3, wherein the scanning laser outputs laser data that the controller analyzes to determine whether an object is detected in the first steer bumper zone or the second steer bumper zone.

6. The method according to claim 1, wherein receiving first sensor data from at least one remote sensing device and receiving second sensor data from at least one remote sensing device comprises:

receiving the first sensor data from at least one ultrasonic sensor; and

receiving the second sensor data from at least one additional ultrasonic sensor.

7. The method according to claim 1, wherein receiving first sensor data from at least one remote sensing device and receiving second sensor data from at least one remote sensing device comprises:

utilizing ultrasonic sensors to detect whether an object is present in the first and second steer bumper zones; and

utilizing at least one scanning laser to verify the results from the ultrasonic sensors.

8. The method according to claim 1, wherein:

performing a steer correction maneuver comprises automatically steer correcting the vehicle by a predetermined steered wheel angle so that the truck angle change as a function of accumulated travel distance is fixed.

9. The method according to claim 8, further comprising fixing the truck angle at between approximately 5 and 10 degrees.

10. The method according to claim 1, wherein accumulating the distance traveled by the materials handling vehicle while automatically steer correcting the vehicle comprises:

accumulating the distance traveled by the vehicle until the detected object is no longer in either the first or second steer bumper zone.

11. The method according to claim 1, wherein automatically counter steering the materials handling vehicle by a predetermined counter steer amount for a percentage of the accumulated steer distance traveled comprises counter steering the materials handling vehicle by an amount of up to one half of the accumulated distance.

12. The method according to claim 1, wherein automatically counter steering the materials handling vehicle comprises counter steering the materials handling vehicle by a steer angle that is up to one half of the corresponding steer angle utilized for steer correcting the vehicle.

13. The method according to claim 1, wherein automatically steer correcting the vehicle by a determined correction amount comprises ramping up the steer angle to a determined fixed value.

14. The method according to claim 1, wherein automatically steer correcting the vehicle by a determined correction amount comprises automatically steer correcting the vehicle by a first determined correction amount if at least one predefined condition is met, and automatically steer correcting the vehicle by a second determined correction amount different than the first determined correction amount under all other circumstances in which the vehicle is to be steer corrected.

15. A materials handling vehicle comprising:

a power unit;

a load handling assembly coupled to said power unit;

at least one contactless sensor mounted to said power unit to detect an object located along a path of travel of said power unit; and

a steer controller coupled to at least one steered wheel of the vehicle to control the steer direction of the vehicle;

a traction controller coupled to a traction motor that drives the at least one steered wheel of the vehicle; and

a master controller coupled to the at least one contactless sensor, the traction controller and the steered wheel controller, the master controller configured to;

receive first sensor data from at least one contactless sensor that defines a first steer bumper zone that is proximate to the materials handling vehicle;

receive second sensor data from at least one contactless that defines a second steer bumper zone that is proximate to the materials handling vehicle;

detect whether an object is in at least one of the first and second steer bumper zones based upon the received sensor data; and

perform a steer correction maneuver if the controller detects an object in at least one of the first and second steer bumper zones by;

automatically determining whether a steer correction maneuver should be to the right or to the left of the traveling direction of the materials handling vehicle based upon the received sensor data defining the first and second steer bumper zones;

performing a first steer correction maneuver if the master controller determines that the object is to the left of the materials handling vehicle by;

automatically steer correcting the vehicle to the right by a determined correction amount;

accumulating the distance traveled by the materials handling vehicle while automatically steer correcting the vehicle to the right; and

automatically counter steering the materials handling vehicle to the left by a determined counter steer amount for a percentage of the accumulated steer distance traveled;

performing a second steer correction maneuver if the master controller determines that the object is to the right of the materials handling vehicle by;

automatically steer correcting the vehicle to the left by the determined amount;

accumulating the distance traveled by the materials handling vehicle while automatically steer correcting the vehicle to the left; and

automatically counter steering the materials handling vehicle to the right by the determined counter steer amount for a percentage of the accumulated steer distance traveled.

16. The materials handling vehicle according to claim 15, wherein the at least one contactless sensor comprises at least one ultrasonic sensor.

17. The materials handling vehicle according to claim 15, further comprising at least one additional contactless sensor that defines at least one detection zone, wherein, the at least one additional contactless sensor is also coupled to the master controller such that a detection zone defines a stop zone where the master controller issues a command to stop the vehicle if the steer correction does not remove the detected obstacle from the first or second steer bumper zone.

18. The materials handling vehicle according to claim 15, wherein automatically steer correcting the vehicle by a determined correction amount comprises automatically steer correcting the vehicle by a first determined correction amount if at least one predefined condition is met, and automatically steer correcting the vehicle by a second determined correction amount different than the first determined correction amount under all other circumstances in which the vehicle is to be steer corrected.