Apparatus and method for determining the position of a point on a work implement attached to and movable relative to a mobile machine

• US 5,987,371 A
• Filed: 12/04/1996
• Issued: 11/16/1999
• Est. Priority Date: 12/04/1996
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Bailey, Scott E., Stratton, Kenneth L.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Donnelly, Arthur D.
• Application Number:
  US08/759,502
• Time in Patent Office: 1,077 Days
• Field of Search: 701/50, 701/207, 701/213, 701/214, 701/216, 340/988, 340/990, 340/991, 37/348, 172/45, 172/9, 342/357, 342/358
• US Class Current: 701/50
• CPC Class Codes: E02F 3/842 using electromagnetic, optical or photoelectric beams, e.g. laser beams
• CPC Class Codes: E02F 3/847 using electromagnetic, optical or acoustic beams to determine the blade position, e.g. laser beams
• CPC Class Codes: E02F 9/2045 Guiding machines along a predetermined path for graders E02F3/841; machines for construction of roads E01C19/004
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

An apparatus and method determines the position of a point on a work implement attached to and movable relative to a mobile machine. The apparatus includes a site coordinate system position sensor mounted on the mobile machine, a ground speed sensor mounted on the mobile machine, an implement position sensor mounted on the mobile machine and coupled to the work implement, and a pitch sensor mounted on the machine. A controller is adapted to receive a reference point position signal from the site coordinate system position sensor, the reference point position signal being indicative of a position of a reference point on the mobile machine in a site coordinate system, to receive an implement position signal from the implement position sensor, a ground speed signal from the ground speed sensor and a pitch signal from the pitch sensor, and to determine the position of the point on the work implement in site coordinates compensating for the pitch of the machine and the translational movement of the machine as a function of the reference point position signal, the implement position signal, the ground speed signal, and the pitch signal.

Claims

1. An apparatus for determining the position of a point on a work implement attached to and movable relative to a mobile machine, comprising:

a site coordinate system position sensor mounted on the mobile machine;

a ground speed sensor mounted on the mobile machine;

an implement position sensor mounted on the mobile machine and coupled to the work implement;

a pitch sensor mounted on the machine;

a controller adapted to receive a reference point position signal from the site coordinate system position sensor, the reference point position signal being indicative of a position of a reference point on the mobile machine in a site coordinate system, to receive an implement position signal from the implement position sensor, a ground speed signal from the ground speed sensor, and a pitch angle signal from the pitch sensor, and to determine the position of the point on the work implement in site coordinates compensating for the pitch of the machine and the translational movement of the machine as a function of the reference point position signal, the implement position signal, the ground speed signal, and the pitch angle signal.

2. An apparatus for determining the position of a point on a work implement attached to and movable relative to a mobile machine, comprising:

site coordinate system position sensing means for sensing the position of a predetermined reference point on the mobile machine in a site coordinate system and responsively producing a reference point position signal;

ground speed sensing means for sensing the ground speed of the mobile machine and responsively producing a ground speed signal;

implement position sensing means for sensing the position of the point on the work implement with respect to the mobile machine and responsively producing an implement position signal;

pitch sensing means for sensing the pitch angle of the mobile machine and responsively producing a pitch angle sensor;

controlling means for receiving the implement position signal, the reference point position signal, the ground speed signal, and the pitch signal and responsively determining the position of the point on the work implement in site coordinates, compensating for the pitch and the translational movement of the machine.

3. A method for determining the position of a point on a work implement attached to and movable relative to a mobile machine, including the steps of:

sensing the position of a predetermined reference point on the mobile machine in a site coordinate system and responsively producing a reference point position signal;

sensing the ground speed of the mobile machine and responsively producing a ground speed signal;

sensing the position of the point on the work implement with respect to the mobile machine and responsively producing an implement position signal;

sensing the pitch angle of the mobile machine and responsively producing a pitch angle signal;

receiving the implement position, the reference point position signal, the ground speed signal, and the pitch signal and responsively determining the position of the point on the work implement in site coordinates while compensating for the pitch and the translational movement of the machine.

4. A method for determining the position of a point on a work implement attached to and movable relative to a mobile machine, the mobile machine operating in a work site having a site coordinate system, the site coordinate system defined by vectors in first and second directions in a horizontal plane and a third direction, the first and second directions being perpendicular and the third direction being perpendicular to the horizontal plane, including the steps of:

sensing a ground speed of the mobile machine and responsively producing a ground speed signal;

sensing a position in site coordinates of a reference point on the mobile machine and responsively producing a reference point position signal;

receiving the reference point position signal, responsively determining a heading of the mobile machine, and responsively producing a heading signal;

sensing a position of the work implement relative to the reference point, responsively determining a machine horizontal distance and machine vertical distance and responsively producing a machine horizontal and vertical distance signals, respectively;

sensing a pitch angle of the mobile machine and responsively producing a machine pitch angle signal;

receiving the machine pitch angle signal and the machine horizontal and vertical distance signals, responsively determining horizontal offset and vertical offset distances in the horizontal plane and in the third direction, respectively, between the reference point and the point on the work implement and responsively producing horizontal and vertical offset distance signals;

receiving the ground speed signal, machine pitch angle signal and the reference point position signal, determining a horizontal and a vertical distance moved since the reference point position signal was valid; and

responsively producing a vertical distance moved signal and a horizontal distance moved signal;

receiving the vertical distance moved and horizontal distance moved signals and the heading signal and the corrected reference point signal, responsively determining a distance moved in the first direction and a distance moved in the second direction, and producing first direction distance moved and second direction distance moved signals;

receiving the vertical distance moved signal and the first and second direction distance moved signals, responsively determining a current position of the reference point in site coordinates and producing a current reference point position signal;

receiving the horizontal distance signal, the vertical distance signal, and the heading signal, responsively determining a distance between the reference point and the point on the work implement in the first direction, a distance between the reference point and the point on the work implement in the second direction, , a distance between the reference point and the point on the work implement in the third direction, and responsively producing first, second, and third position difference signals, respectively; and

receiving the current reference point position signal and the first, second, and third position difference signals and responsively determining the position of a point on the work implement in site coordinates.