Apparatus and method for controlling a hydraulic excavator

A system for an excavator for use with a laser emitting a planar laser beam at a predetermined elevation, said excavator having a fame, cutting means, connecting means for connecting said cutting means to said frame and actuation means for moving said cutting means with respect to a point on said frame, said system comprising:

• laser receiving means on said connecting means for producing a signal when contacted by the laser beam;
• laser receiving means relative position determining means for producing a first representation proportional to the distance between said laser receiving means when contact by the laser beam and said point;
• means for storing said first representation;
• cutting means relative position determining means for producing a second representation proportional to the distance between said cutting means and said point;
• and
• cutting means absolute position determining means for combining said first and second representations to produce a third representation proportional to the distance of said cutting means from the laser plane;
• and
• automatic control means responsive to aid third representation for producing a first output for controlling said actuation means.

A system for an excavator for use with a laser emitting a planar laser beam at a predetermined elevation, said excavator having a frame, cutting means, connecting means for connecting said cutting means to said frame and actuation means for moving said cutting means with respect to a point on said frame, said system comprising:

• laser receiving means on said connecting means for producing a signal when contacted by the laser beam;
• laser receiving means relative position determining means for producing a first representation proportional to the distance between said laser receiving means when contacted by the laser beam and said point;
• means for storing said first representation;
• cutting means relative position determining means for producing a second representation proportional to the distance between said cutting means and said point;
• and
• cutting means absolute position determining means for combining said first and second representations to produce a third representation proportional to the distance of said cutting means from the laser plane;
• wherein said laser receiving means comprises a linear array of laser receptors and wherein said signal comprises a fourth representation proportional to the distance from a preselected reference point on said connecting means to a single receptor contacted by a laser beam and further wherein said fourth representation is proportional to the distance from said preselected reference point to the longitudinally centermost receptor in a group of receptors contacted by a laser beam.

A system for an excavator for use with a laser emitting a planar laser beam at a predetermined elevation, said excavator having a frame, cutting means, connecting means for connecting said cutting means to said frame and actuation means for moving said cutting means with respect to a point on said frame, said connecting means including a boom pivotally mounted at a proximal end thereof to said frame, a stick pivotally mounted at a proximal end thereof to a distal end of said boom and a bucket pivotally mounted at a proximal end thereof to a distal end of said stick, a distal end of said boom and a bucket pivotally mounted at a proximal end thereof to a distal end of said stick, a distal end of said bucket defining said cutting means and wherein said laser receiving means is on said stick, said system comprising:

• laser receiving means on said connecting means for producing a signal when contacted by the laser beam;
• laser receiving means relative position determining means for producing a first representation proportional to the distance between said laser receiving means when contacted by the laser beam and said point;
• means for storing said first representation;
• cutting means relative position determining means for producing a second representation proportional to the distance between said cutting means and said point;
• and
• cutting means absolute position determining means for combining said first and second representations to produce a third representation proportional to the distance of said cutting means from the laser plane;
• wherein said laser receiving means relative position sensing means comprises a vertically sensing means for producing a first angle representation proportional to the angle between said frame and a true vertical plane, a boom angle sensing means for producing a second angle representation proportional to the angle between said frame and said boom, a stick angle sensing means for producing a third angle representation proportional to the angle between said boom and said stick and calculating means for calculating said laser receiving means relative position from said angle representations.

A method of operating an excavator having a frame, cutting means, connecting means for connecting said cutting means to said frame and actuation means for moving said cutting means with respect to a first point on said frame, said method comprising the steps:

• establishing a reference plane at a preselected orientation to a preselected coordinate system;
• selecting a second point on said connecting means;
• operating said actuation means in a manner that occasionally causes a momentary coincidence between said second point and said plane;
• producing a first representation proportional to the distance between said first and second points simultaneous with each said momentary coincidence;
• storing said first representation as a calibration number;
• producing second representations repetitively between occurrences of said momentary coincidences, said second representations being proportional to the distance between said cutting means and said first point;
• comparing said second representations with said calibration number to repetitively produce third representations proportional to the distance of said cutting means from said reference plane;
• and
• updating said calibration number after each said momentary coincidence.

A method of operating an excavator having a frame, cutting means, connecting means for connecting said cutting means to said frame and actuation means for moving said cutting means with respect to a first point on said frame, said method comprising the steps:

• establishing a reference plane by generating an angularly rotating laser beam in said reference plane at a preselected orientation with respect to earth;
• selecting a second point on said connecting means;
• operating said actuation means to cause a momentary coincidence between said second point and said plane;
• producing a first representation proportional to the distance between said first and second points simultaneous with said coincidence;
• storing said first representation;
• producing a second representation proportion al the distance between said cutting means and said fist point;
• combining said first and second representations to produce a third representation whereby the third representation will be proportional to the distance of said cutting means from said reference plane;
• wherein said step of operating comprises operating said excavator in a manner that causes said connecting means to occasionally cross said reference plane without pausing while crossing said plane.

A method of operating an excavator having a frame, cutting means, connecting means for connecting said cutting means to said frame and actuation means for moving said cutting means with respect to a first point on said frame said method comprising the steps:

• establishing a reference plane by generating an angularly rotating laser beam in said reference plane at a preselected orientation with respect to earth;
• selecting a second point on said connecting means;
• operating said actuation means to cause a momentary coincidence between said second point and said plane;
• producing a first representation proportional to the distance between said first and second point simultaneous with said coincidence;
• storing said first representation;
• producing a second representation proportional to the distance between said cutting means and said first point;
• combining said first and second representations to produce a third representation whereby the third representation will be proportional to the distance of said cutting means from said reference plane;
• and
• selecting a desired distance from said reference plane that it is desired for said cutting means to excavate to, comparing said third representation with said desired distance and controlling said actuation means so as to cause said cutting means to approach said desired distance.