Forklift alignment system

• US 5,208,753 A
• Filed: 03/28/1991
• Issued: 05/04/1993
• Est. Priority Date: 03/28/1991
• Status: Expired due to Fees

• Current Assignee: Dallas W. Acuff
• Original Assignee: Dallas W. Acuff
• Inventors: Acuff, Dallas W.
• Primary Examiner(s): Black, Thomas G.
• Application Number:
  US07/676,525
• Time in Patent Office: 768 Days
• Field of Search: 364/424.07, 364/424.01, 364/424.02, 364/571.01, 364/571.08, 318/568.13, 318/568.14, 318/568.16, 414/612, 414/615, 414/631, 414/633
• US Class Current: 701/50
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: G05B 2219/37555 Camera detects orientation, position workpiece, points of workpiece
• CPC Class Codes: G05B 2219/45049 Forklift

Abstract

A digital computer based power control system for automatically aligning a first, moveable object with a second, fixed object to aid a human operator in effecting contact or engagement of the first object with the second object in a precise manner. A camera and light assembly on the first object form images of the second object as the first object is automatically positioned. These images are stored in digital form and compared to an ideal image which indicated proper alignment of the first and second objects. This condition is indicated to the human operator to allow movement of the first object to the point of proper alignment. The system includes a main processor, a ROM for storage of control programs, RAM for storage of images, a camera and light assembly, operator controls, and power electronics. A typical application of the power control system is a forklift controller for automatically aligning the forks with a pallet to aid the operator in engaging the forklift truck with the pallet in a precise manner.

Claims

1. Apparatus for alignment of a forklift truck with a pallet including:

a control system having a processor including first and second storages, a scanner assembly, controls for movement of forks on said forklift truck, an operator control unit;

said first storage for storage of said pallet image when said pallet is in a selected ideal position with the forks of said forklift truck;

said second storage for storage of successive images obtained by the scanning of said pallet by said scanner assembly while said forks of said forklift truck are automatically moved by said controls;

said processor performing a compare function of said first and second storages as successive images are placed in said second storage;

said processor generating a signal when an equal compare condition is obtained;

said signal controlling said controls to stop movement of said forks;

said signal also indicating to said operator control unit that said forks of said forklift truck are in said selected ideal position to engage said pallet.

2. The apparatus as in claim 1 wherein said controls are hydraulic and move said forks in either a horizontal or vertical direction under control of said control system.

3. The apparatus of claim 1 wherein said scanner assembly includes a camera, a light source and a frame grabber module.

4. The apparatus as in claim 3 wherein said frame grabber module includes an analog sampler, an analog to digital converter, and a frame grabber storage module which function to receive analog signals from said camera in a repetitive series, convert said repetitive series of analog signals to digital form and store the digital series in said frame grabber storage module.

5. The apparatus as in claim 4 wherein said frame grabber module transfers said digital series from said frame grabber storage module to said second storage in said processor.

6. The apparatus of claim 1 wherein said operator control unit includes:

a manual/automatic switch;

a display monitor for viewing the image of said pallet taken by said camera and light source

a calibration switch which is used during a calibration procedure to store said selected ideal position of said pallet;

an alignment indicator which indicates to the operator that the alignment of said forks is complete when said selected ideal position has been reached.

7. A method for calibrating a forklift control system to store the image of an ideal position of a pallet in relation to the forks of a forklift truck by the following steps:

a) moving said forklift truck to face said pallet at a distance of approximately 7 feet from the front of the forklift truck to the pallet;

b) viewing the pallet image on a display monitor connected to a camera on said forklift truck;

c) adjusting said forks and said forklift truck to be in a position that if the forklift truck were moved directly forward the forks would engage the pallet in an ideal manner as judged by a trained operator;

d) storing under control of a switch the pallet image shown on said display monitor which represents the ideal position into a video storage.

8. A method of operating a system for alignment of a forklift truck with a pallet including the following steps:

a) calibrating said system to store an image of an ideal position for said pallet to be engaged by the forks of said forklift truck using a video monitor;

b) moving said forklift truck in manual mode by an operator into an approximate position for engaging said pallet by said forks;

c) switching said system from manual mode to automatic mode by said operator;

d) moving said forks in automatic mode;

e) scanning of said pallet during automatic mode to obtain a series of images of said pallet as said forks are moved;

f) comparing said series of images of said pallet with said ideal position;

stopping said forks when said ideal position has been reached as indicated by said comparing step;

h) switching said system from automatic to manual mode by said operator; and

i) moving said forklift truck by said operator to engage said pallet.

9. Apparatus for alignment of a first moveable object with a second fixed object including:

a control system having a processor including first and second storages, a scanner assembly, a power control system for moving the first object, and operator controls;

said first storage for storage of image of said first object when said second object is in a selected ideal position relative to the said first object;

said second storage for storage of successive images obtaining by the scanning of said second object by said scanner assembly while said first object is automatically moved by said power control system;

said processor performing a compare function of said first and second storages as successive images are placed in said second storage;

said processor generating a signal when an equal compare condition is obtained;

said signal controlling said power control system to stop movement of said first object;

said signal also indicating to said operator that said first object is in said selected ideal position to contact or engage said second object.

10. The apparatus as in claim 9 wherein said power control system moves said first object in either a horizontal or vertical direction under control of said control system.

11. The apparatus of claim 9 wherein said operator controls include:

a manual/automatic toggle switch;

a display monitor for viewing the image of said second object taken by said camera and light source during the calibration phase;

a calibration switch which is used during a calibration procedure to store said selected ideal position of said second object;

an alignment indicator which indicates to the operator that the alignment of said first object is complete when said selected ideal position has been reached.

12. A method for calibrating a power control system to store the image of an ideal position for a first object in relation to a second object by the following steps:

a) moving said first object to face said second object at a distance of 1-3 meters from the front of the said first object to the said second object;

b) viewing the image of the said second object on a display monitor connected to a camera on the said first object;

c) adjusting said first object to be in a position so that if the said first object were moved directly forward, the said first object would contact or engage the said second object in an ideal manner as judged by a human expert; and

d) storing under control of a switch the image of the said second object as shown on said display monitor which represents the ideal position in video storage.

13. A method of operating a system for alignment of a first object with a second object including the following steps:

a) calibrating said system to store an image of an ideal position for said second object to be contacted or engaged by the said first object using a video monitor;

b) moving said first object in manual mode by an operator into an approximate position for contacting or engaging said first object;

c) switching said system from manual mode to automatic mode by said operator;

d) moving said first object in automatic mode;

e) scanning of said second object during automatic mode to obtain a series of images of said second object as said first object is being moved;

f) comparing said series of images of said second object with said ideal position;

g) stopping said first object when said ideal position has been reached as indicated by said comparing step;

h) switching said system from automatic mode to manual mode by said operator; and

i) moving said first object by said operator to contact or engage said second object.