Method for carrying out automatic surface finishing work with electro-hydraulic excavator vehicle

• US 5,768,810 A
• Filed: 11/22/1996
• Issued: 06/23/1998
• Est. Priority Date: 04/29/1994
• Status: Expired due to Fees

• Current Assignee: Volvo Construction Equipment Holding Sweden AB
• Original Assignee: Samsung Heavy Industries Company Limited (Samsung Group)
• Inventors: Ahn, Seong-Ho
• Primary Examiner(s): Melius, Terry Lee
• Assistant Examiner(s): BATSON, VICTOR D
• Application Number:
  US08/754,919
• Time in Patent Office: 578 Days
• Field of Search: 37/348, 37/902, 37/443, 37/382, 364/424.07, 414/699, 414/695.5, 172/2, 172/4.5
• US Class Current: 37/348
• CPC Class Codes: E02F 3/436 for keeping the dipper in the horizontal position, e.g. self-levelling
• CPC Class Codes: E02F 3/437 providing automatic sequences of movements, e.g. linear excavation, keeping dipper angle constant
• CPC Class Codes: E02F 9/2025 Particular purposes of control systems not otherwise provided for E02F3/16, E02F3/26, sub-groups of E02F3/43, E02F3/651, sub-groups of E02F3/84, E02F3/907, E02F5/145 take precedence

Abstract

A method for carrying out a surface finishing work with an electronically controlled hydraulic excavator is disclosed. The present invention includes the steps of: selecting an automatic surface finishing work, and inputting a desired work angle (S1); detecting the current positions of the respective attachment (S32); deciding the bucket maintaining angle relative to the horizontal plane (S3); correcting the work angle relative to the equipment inclination (S4); judging as to whether the control lever for the dipper stick is manipulated by the operator (S7); judging as to whether or not there is a swinging operation by the operator (S9); correcting the swinging angle and the inclination angle when carrying out the swinging operation (S10); compensating the departure amount of the bucket end from the initially inputted work plane during the swinging (S11); calculating the linear velocity of the bucket end L which is proportionate to the actuation of the control lever for the dipper stick (S12); deciding a velocity for satisfying the positions of the cylinders corresponding to the intended angles of the bucket, the dipper stick and the boom (S15); making corrections for feasible velocities calculating the target velocities of the respective cylinders for arriving to the target positions (S17); correcting the velocities of the cylinders compensating the velocity of the cylinders and the fluid discharge amount of the pump (S19); and terminating the operation after the end of the work (S21).

Claims

1. A method for surface finishing work with an electronically controlled hydraulic excavator comprising the steps:

inputting a command to operate the electronically controlled hydraulic excavator to excavate the around with a bucket at an angle θ

relative to a horizontal reference;

determining if a swinging operation of an upper rotary portion carrying the bucket of the electronically controlled hydraulic excavator about an axis orthogonal to the ground is being performed;

in response to the determined swinging operation of the upper rotary portion calculating a deviation of an end L of the bucket from the angle θ

; and

compensating for the calculated deviation of the bucket end L from the angle θ

automatically by moving the bucket end L from the calculated deviation back to the angle θ

for performing the finishing work.

2. A method for surface finishing work with an electronically controlled hydraulic excavator comprising the steps:

determining an initial position of a bucket end L and a pivot point of a bucket joint J in a rectangular coordinate system with an origin of a coordinate system being a connection point A between a boom and an upper rotary portion of the electronically controlled hydraulic excavator;

judging if a control lever is manipulated when carrying out the surface finishing work by driving one of a bucket, a dipper stick or the boom;

calculating a deviation amount of the bucket end L from a desired work angle θ

relative to a work plane which is set by a driver of the electronically controlled hydraulic excavator to provide compensation for deviation from the desired work angle θ

when the bucket end L deviates from the work plane during revolution of the upper rotary portion of the electronically controlled hydraulic excavator;

calculating a linear velocity of the bucket end L which is proportionate to an actuation of the control lever;

determining linear velocities of a plurality of hydraulic cylinders for driving the bucket, dipper stick and the boom for satisfying a next hydraulic cylinder position d_i of one of the plurality of hydraulic cylinders which is a length between a pivot point B and pivot point C, a next hydraulic position of another one of the plurality of hydraulic cylinders d₂ which is a length between a pivot point D and pivot point F and a next hydraulic cylinder position of another one of the plurality of hydraulic cylinders d₃ which is the length between a pivot point G and a pivot point I corresponding to revolution angles θ

₁, θ

₂, θ

₃ of the bucket, the dipper stick and the boom;

compensating for the linear velocities of the plurality of hydraulic cylinders based on the next hydraulic cylinder position obtained from a current work status which is measured by a position sensor and is based on a discharged amount of fluid from a plurality of hydraulic pumps providing fluid to the plurality of hydraulic cylinders; and

outputting voltages to amplifiers of a main control valve and pump based on compensating for the linear velocities of the plurality of hydraulic cylinders.

3. A method for surface finishing work with an electronically controlled hydraulic excavator comprising the steps:

inputting a desired work angle into a processor;

detecting current signal values of angles for a boom, a dipper stick and a bucket, a turning angle of swinging of an upper portion of the electronically controlled hydraulic excavator, an inclination angle of the upper portion of the electronically controlled hydraulic excavator, and a rolling angle of the electronically controlled hydraulic excavator;

determining a bucket maintaining angle relative to a horizontal plane based on the detected current signal values;

correcting the desired work angle for an absolute horizontal surface relative to the inclination of the electronically controlled hydraulic excavator;

obtaining initial positions of a bucket end and a pivot point of the bucket with respect to a rectangular coordinate system having a first origin;

obtaining the initial position of the bucket end with respect to a rectangular coordinate system having a second origin;

determining if a control level for the dipper stick has been manipulated;

calculating a current position of the pivot point of the bucket relative to the rectangular coordinate system having the first origin when the control level for the dipper stick has been manipulated;

determining if a swinging operation of the upper portion of the electronically controlled hydraulic excavator has been made;

correcting a swinging angle and an inclination angle of the electronically controlled hydraulic excavator if the swinging operation has been made;

calculating and compensating for a deviation of the bucket end from an initially inputted work plane during the swinging operation;

calculating a linear velocity of the bucket end based on an original position of the control lever for the dipper stick;

determining a next position of the pivot point of the bucket relative to the rectangular coordinate system having the first origin;

calculating target angles of the boom, the dipper stick, and the bucket for maintaining an initial bucket angle;

calculating velocities of a plurality of cylinders which respectively drive the bucket, boom and dipper stick;

modifying the calculated velocities of the plurality of cylinders without varying a velocity ratio of the plurality of cylinders within a range of discharge fluid quantity of a plurality of pumps which supply fluid to the plurality of cylinders, and re-setting intended positions of the plurality of cylinders;

calculating target velocities of the plurality of cylinders for arriving at target positions of the bucket, boom and dipper stick;

correcting the calculated target velocities of the plurality of cylinders and current dischargeable amounts of the fluid from the plurality of pumps while maintaining the velocity ratio of the plurality of cylinders;

compensating for the velocity of the plurality of cylinders and the discharge fluid quantity of the plurality of pumps; and

outputting voltages to amplifiers of a main control valve and the plurality of pumps based on the compensating for the velocity.

4. A method for according to claim 3, wherein:

the rectangular system has the first origin where the upper portion and the boom are connected together.

5. A method for according to claim 3, wherein the rectangular system having the second origin is a central point of a lower portion of a wheel of the electronically controlled hydraulic excavator.

6. A method for carrying out automatic surface finishing work while compensating for a deviation of a bucket end point L automatically when the bucket end point L departs from a work plane during revolution of an upper rotary portion of an electronically controlled hydraulic excavator comprising the steps:

selecting an automatic surface finishing work and inputting a desired work angle θ

W into a processor on a keypad by a driver of the electronically controlled excavator;

detecting and reading a current rotational angle of a boom θ

bm with respect to a pivot point A, a rotational angle of a dipper stick θ

ds with respect to a pivot point E and a rotational angle of bucket θ

bk with respect to a pivot point H, a revolution angle of an upper rotary portion of the electronically controlled excavator with respect to an axis Y and a slope angle θ

p, θ

r of the upper rotary portion with respect to axes Z and X with a plurality of position sensors with the axes X, Y and Z being in a rectangular coordinate system;

determining a bucket maintaining angle θ

which is summation of the boom angle θ

bm, dipper stick angle θ

ds and bucket angle θ

bk;

correcting a work angle τ

to make the desired work angle θ

W fit to an absolute horizontal plane which is a surface of the earth;

deciding initial positions of a bucket end L and a pivot point of a bucket joint J in a rectangular coordinate system with an origin of the rectangular coordinate system being a connection point A between the boom and the upper rotary portion;

determining the initial position of the bucket end L in a rectangular coordinate system with an origin of the rectangular coordinate system being a central point O touching on the work plane;

judging if a control lever for the dipper stick is manipulated when carrying out the automatic surface finishing work by driving one of an attachment, the bucket, the dipper stick and the boom and outputting voltages to an amplifier of a main control valve and pump if the control lever has not been manipulated;

determining a current position of the bucket joint J in a rectangular coordinate system having an origin at point A after manipulation of the control lever for the dipper stick;

determining if there is a revolving of the upper rotary portion by a driver of the electronically controlled excavator vehicle, and calculating a linear velocity of the bucket end L which is proportionate to actuation of the control lever of the dipper stick if there is no operation;

reading a revolution angle θ

SW of the upper rotary portion with respect to a Y axis in a coordinate system having X, Y and Z axes and a slope angle, θ

p or θ

r of the rotary upper portion with respect to the Z or X axes to correct the work angle T when carrying out revolution of the upper rotary portion;

calculating a deviation amount of the bucket end L from the desired work angle θ

W to provide compensation for deviation from the desired work angle when the bucket end L departs from the work plane during revolution of the upper rotary portion;

calculating a linear velocity of the bucket end L which is proportionate to actuation of the control lever of the dipper stick;

determining values of a next position to which the pivot point of the bucket joint J is to be positioned in the rectangular coordinate system having the original of a central point O;

determining a boom angle θ

bm, a dipper stick angle θ

ds for a position of bucket pivot point and a bucket angle θ

bk for maintaining an initial bucket angle in the coordinate system having the origin at the point A;

determining linear velocities of a plurality of hydraulic cylinders for satisfying next hydraulic cylinder position d₁ which is the length between a pivot point B and a pivot point C, another hydraulic cylinder position d₂ which is a length between a pivot point D and a pivot point F and another hydraulic cylinder position d₃ which is the length between pivot point G and a pivot point I corresponding to the revolution angles θ

bk, θ

ds, θ

bm of the bucket, the dipper stick and the boom;

making corrections for possible velocities without varying a velocity ratio of the plurality of hydraulic cylinders within a range of the dischargeable fluid quantity from a plurality of hydraulic pumps which provide fluid to the plurality of hydraulic cylinders and resetting next target positions of the plurality of hydraulic cylinders which drive the boom, dipper and bucket;

calculating target velocities of the plurality of hydraulic cylinders at target positions by utilizing the target positions of the plurality of hydraulic cylinders by a position control section;

correcting target velocities of the plurality of hydraulic cylinders and a current amount of the fluid dischargeable from the plurality of hydraulic pumps, while maintaining the velocity ratio of the plurality of hydraulic cylinders;

compensating target velocities of the plurality of hydraulic cylinders based on the position values obtained from a current work status which is measured by a position sensor and based on a discharged quantity of hydraulic fluid from the plurality of pumps;

converting compensated velocity signals into analog signals by first and second digital to analog converters for outputting a voltage to a first amplifier and to a second amplifier for a main control valve so as to output currents through first and second electronic proportional valves and activating the hydraulic pumps with the output currents to drive the plurality of hydraulic cylinders within the main control valve; and

terminating operation after an end of surface finishing work if the driver of the electronically controlled hydraulic excavator has inputted a release signal for the surface finishing work and returning to manipulating the control lever of the dipper stick if the release signal has not been inputted.