Laser reference system for excavating machine

• US 6,691,437 B1
• Filed: 03/24/2003
• Issued: 02/17/2004
• Est. Priority Date: 03/24/2003
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Yost, Jerald W., Pope, Richard M. Jr.
• Primary Examiner(s): Novosad, Christopher J.
• Application Number:
  US10/395,326
• Time in Patent Office: 330 Days
• Field of Search: 701/50, 172/4, 172/2, 172/4.5, 373/48, 373/82, 356/141.1, 356/141.2, 356/141.3, 356/72, 356/912, 414/698, 414/699
• US Class Current: 37/348
• CPC Class Codes: E02F 3/435 for dipper-arms, backhoes or the like
• CPC Class Codes: G01C 15/006 Detectors therefor

Abstract

A level sensing system for use with an excavating machine includes a light receiving sensor, mounted on the dipper stick of the machine, and an inclinometer, also mounted on the dipper stick of the machine. The sensor and inclinometer provide indications of the relative location of a beam of light and the inclination of the dipper stick. The inclinometer includes a gyroscopic inclination sensor and an accelerometer arrangement for sensing acceleration due to gravity and providing a static vertical reference. A position determining circuit is responsive to the sensor and the inclinometer and calculates the position of a pivot joint on the dipper stick to which a digging bucket is attached. The beam of light is a beam of laser light which is projected by a laser transmitter. An angle-measuring sensor may be provided for measuring the angular orientation between the dipper stick and a cutting edge of the bucket.

Claims

1. A level sensing system for use with an excavating machine of the type having a chassis, a boom pivotally secured to said chassis at a first pivot joint, a dipper stick pivotally secured to said boom at a second pivot joint, and a bucket pivotally secured to said dipper stick at a third pivot joint, comprising:

a light receiving sensor, mounted on said dipper stick and providing an indication of the relative location of a beam of light striking said light receiving sensor,

an inclinometer, mounted on said dipper stick and providing an indication of the inclination of said dipper stick, said inclinometer including a gyroscopic inclination sensor and an accelerometer arrangement for sensing acceleration due to gravity and providing a static vertical reference, and

a position determining circuit, responsive to said sensor and said inclinometer, for calculating the position of said third pivot joint based on the inclination of said dipper stick and on the relative location of said beam of light striking said light receiving sensor.

2. The level sensing system as recited in claim 1, wherein said beam of light is a beam of laser light which is projected by a laser transmitter and rotated to define a reference plane of laser light, and wherein said light receiving sensor comprises an elongated photocell structure responsive to laser light and providing a linear indication of the relative location of said beam to said position determining circuit.

3. The level sensing system as recited in claim 2, further comprising:

at least one angle-measuring sensor for measuring the angular orientation between said dipstick and a cutting edge of said bucket and providing an indication of said angular orientation to said position determining circuit, whereby the location of the cutting edge of the bucket may be determined.

4. A level sensing system for use on a digging machine, said system comprising:

a light receiving sensor, mounted on a machine element, providing an indication of the location of reference light striking said sensor, said location being a predetermined distance above a digging elevation, said light receiving sensor comprising an elongated photocell arrangement,

a gyroscopic inclinometer, mounted on said machine element, including an accelerometer compensating for long term drift, and

a circuit for calculating the position of a point on said machine element based on the location of the light striking the sensor and on the inclination of said machine element, as indicated by said inclinometer, whereby digging may be effected at said digging elevation by means of a digging element secured to said machine element at said point.

5. The level sensing system as recited in claim 4, wherein said machine element is a dipper stick, and wherein said digging element is a bucket, pivotally mounted at said point on said dipper stick.

6. The level sensing system as recited in claim 5, further comprising an angle-measuring sensor providing an indication of the angle between said dipper stick and said bucket, and wherein said circuit is responsive to said angle-measuring sensor for determining the location of a cutting edge of said bucket.

7. A level sensing system for use on an excavating machine of the type having a downwardly extending dipper stick, comprising:

a light receiving sensor which provides an indication as to a location of a moving beam of light illuminating the light receiving sensor; and

an angle-measuring sensor which provides an indication of an orientation of said dipper stick with respect to a gravity reference;

wherein said light receiving and angle measuring sensors provide distance information and orientation information, said distance information being the distance between the light-receiving sensor and a digging elevation, and the orientation information being the orientation of the dipper stick with respect to a vertical reference;

wherein said angle-measuring sensor includes a gyroscopic inclinometer having accelerometers for preventing drift; and

wherein said moving beam of light comprises a rotating laser light beam, and said light receiving sensor comprises an elongated photocell arrangement responsive to laser light.

8. The level sensing system as recited in claim 7, in which a bucket is pivotally mounted at one end of said dipper stick, said bucket including a digging edge, and further comprising a second angle-measuring sensor responsive to an angle between said dipper stick and said bucket.

9. The level sensing system as recited in claim 7 in which said light receiving sensor is mounted for movement with said dipper stick.