Calibration device for work machine and calibration method of working equipment parameter for work machine

1. A calibration device for a work machine, the work machine comprising:

a work machine body;

working equipment swingably connected to the work machine body, the working equipment comprising:

a first actuation unit swingably connected to the work machine body, the first actuation unit being configured to be actuated by a first hydraulic cylinder provided to the work machine body; and

a second actuation unit swingably connected to the first actuation unit, the second actuation unit being configured to be actuated by a second hydraulic cylinder provided to the first actuation unit;

a first swing angle detector configured to detect swing angle information of the first actuation unit relative to the work machine body;

a second swing angle detector configured to detect swing angle information of the second actuation unit relative to the first actuation unit;

an attitude calculating unit configured to calculate respective attitudes of the first actuation unit and the second actuation unit based on the detected swing angle information of the first actuation unit and the second actuation unit; and

an estimated position calculating unit configured to calculate an estimated position of a reference point of the first actuation unit based on a working equipment parameter related to a member of the first actuation unit and the attitude of the first actuation unit calculated by the attitude calculating unit and calculate an estimated position of a reference point of the second actuation unit based on a working equipment parameter related to a member of the second actuation unit and the attitude of the second actuation unit calculated by the attitude calculating unit, the calibration device being provided to the work machine to calibrate the working equipment parameters, the calibration device comprising:

a measurement value acquiring unit configured to acquire a measurement value of a reference point of the work machine body, a measurement value of the reference point of the first actuation unit and a measurement value of the reference point of the second actuation unit, the measurement values being measured using an external measurement device;

a working equipment parameter acquiring unit configured to acquire the working equipment parameter related to the member of the first actuation unit and the working equipment parameter related to the member of the second actuation unit, the working equipment parameters being used by the estimated position calculating unit;

a first calibration unit configured to calibrate the working equipment parameter related to the member of the first actuation unit based on the respective measurement values of the reference points of the work machine body and the first actuation unit measured by the measurement value acquiring unit; and

a second calibration unit configured to calibrate the working equipment parameter related to the member of the second actuation unit based on the working equipment parameter related to the member of the first actuation unit calibrated by the first calibration unit and the respective measurement values of the reference points of the work machine body, the first actuation unit and the second actuation unit acquired by the measurement value acquiring unit.

2. The calibration device for the work machine according to claim 1 , wherein the first swing angle detector and the second swing angle detector are respectively provided to the first hydraulic cylinder and the second hydraulic cylinder, and each comprise a stroke displacement detector that detects a stroke displacement of the first hydraulic cylinder or the second hydraulic cylinder.

3. The calibration device for the work machine according to claim 2 , wherein

the work machine further comprises an encoder configured to detect a swing angle of the first actuation unit relative to the work machine body, and

the attitude calculating unit calibrates a reference position of the stroke displacement detector based on a reference position of the swing angle of the first actuation unit detected by the encoder.

4. The calibration device for the work machine according to claim 1 , wherein

the first calibration unit calibrates the working equipment parameter related to the member of the first actuation unit by repeating convergence calculation until a numerical analytic formula comprising the working equipment parameter related to the member of the first actuation unit and the measurement value of the reference point of the first actuation unit is converged within a predetermined acceptable error range,

the second calibration unit calibrates the working equipment parameter related to the member of the second actuation unit by repeating convergence calculation until a numerical analytic formula comprising the working equipment parameter related to the member of the second actuation unit and the measurement value of the reference point of the second actuation unit is converged within a predetermined acceptable error range, and

the acceptable error range for the second calibration unit is larger than the acceptable error range for the first calibration unit.

5. The calibration device for the work machine according to claim 1 , wherein

the first actuation unit comprises:

a boom swingably connected to the work machine body with a pin to be actuated by a boom cylinder provided to the work machine body; and

an arm swingably connected to a distal end of the boom with a pin to be actuated by an arm cylinder provided to the boom,

the second actuation unit comprises a bucket connected to a distal end of the arm with a pin,

the reference point of the first actuation unit is defined by the pin at the distal end of the arm, and

the reference point of the second actuation unit is defined by a distal end of the bucket in a work direction.

6. The calibration device for the work machine according to claim 5 , wherein

the first calibration unit calibrates the working equipment parameter related to the member of the first actuation unit based on three attitudes of the work machine, and

the second calibration unit calibrates the working equipment parameter related to the member of the second actuation unit based on two attitudes of the work machine.

7. A calibration device for a work machine, the work machine comprising:

a work machine body;

working equipment swingably connected to the work machine body, the working equipment comprising:

a boom swingably connected to the work machine body, the boom being configured to be actuated by a boom cylinder provided to the work machine body;

an arm swingably connected to the boom, the arm being configured to be actuated by an arm cylinder provided to the boom; and

a bucket swingably connected to the arm, the bucket being configured to be actuated by a bucket cylinder provided to the arm,

a boom swing angle detector configured to detect swing angle information of the boom relative to the work machine body;

an arm swing angle detector configured to detect swing angle information of the arm relative to the boom;

a bucket swing angle detector configured to detect swing angle information of the bucket relative to the arm;

an attitude calculating unit configured to calculate attitudes of the boom, the arm and the bucket respectively based on the detected swing angle information detected by the boom swing angle detector, the arm swing angle detector and the bucket swing angle detector; and

an estimated position calculating unit configured to calculate an estimated position of a blade edge of the bucket based on a working equipment parameter related to the boom, a working equipment parameter related to the arm, a working equipment parameter related to the bucket and the respective attitudes of the boom, the arm and the bucket calculated by the attitude calculating unit, the calibration device being provided to the work machine to calibrate the working equipment parameters, the calibration device comprising:

a measurement value acquiring unit configured to acquire a measurement value of a reference point of the work machine body, a measurement value of a reference point of the boom, a measurement value of a reference point of the arm and a measurement value of a reference point of the bucket, the measurement values being measured by an external measurement device;

a working equipment parameter acquiring unit configured to acquire the working equipment parameters related to the boom, the arm and the bucket, the working equipment parameters being used by the estimated position calculating unit;

a first calibration unit configured to calibrate the working equipment parameters related to the boom and the arm based on the respective measurement values of the reference points of the work machine body, the boom and the arm acquired by the measurement value acquiring unit; and

a second calibration unit configured to calibrate the working equipment parameter related to the bucket based on the working equipment parameters related to the boom and the arm calibrated by the first calibration unit and the respective measurement values of the reference points of the work machine body, the boom, the arm and the bucket acquired by the measurement value acquiring unit.

8. A calibration method for a work machine, the work machine comprising:

a work machine body;

working equipment swingably connected to the work machine body, the working equipment comprising:

a first actuation unit swingably connected to the work machine body, the first actuation unit being configured to be actuated by a first hydraulic cylinder provided to the work machine body; and

a second actuation unit swingably connected to the first actuation unit, the second actuation unit being configured to be actuated by a second hydraulic cylinder provided to the first actuation unit;

a first swing angle detector configured to detect swing angle information of the first actuation unit relative to the work machine body;

a second swing angle detector configured to detect swing angle information of the second actuation unit relative to the first actuation unit;

an attitude calculating unit configured to calculate respective attitudes of the first actuation unit and the second actuation unit based on the detected swing angle information of the first actuation unit and the second actuation unit; and

an estimated position calculating unit configured to calculate an estimated position of a reference point of the first actuation unit based on a working equipment parameter related to a member of the first actuation unit and the attitude of the first actuation unit calculated by the attitude calculating unit and calculate an estimated position of a reference point of the second actuation unit based on a working equipment parameter related to a member of the second actuation unit and the attitude of the second actuation unit calculated by the attitude calculating unit, the calibration method being performed in the work machine to calibrate the working equipment parameters, the calibration method comprising:

acquiring the working equipment parameter related to the member related to the first actuation unit and the working equipment parameter related to the member related to the second actuation unit;

acquiring a measurement value of a reference point of the work machine body, a measurement value of the reference point of the first actuation unit and a measurement value of the reference point of the second actuation unit, the measurement values being measured by an external measurement device;

calibrating the working equipment parameter related to the member of the first actuation unit based on the measurement value of the reference point of the work machine body and the measurement value of the reference point of the first actuation unit; and

calibrating the working equipment parameter related to the member of the second actuation unit based on the calibrated working equipment parameter related to the member of the first actuation unit and the respective measurement values of the reference points of the work machine body, the first actuation unit and the second actuation unit.