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

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

• an arm;
• a bucket swingably connected to the arm;
• a hydraulic cylinder swingably connected to the arm to actuate the bucket;
• a first link member having a first end rotatably connected to a distal end of the hydraulic cylinder and a second end rotatably connected to the arm;
• a second link member having a first end rotatably connected to a distal end of the hydraulic cylinder and a second end rotatably connected to the bucket;
• a swing angle detector configured to detect swing angle information of the bucket relative to the arm;
• an attitude calculating unit configured to calculate respective attitudes of the arm and the bucket based on the detected swing angle information of the bucket;
• and
• an estimated position calculating unit configured to calculate an estimated position of a reference point of the bucket based on a working equipment parameter related to the arm, a working equipment parameter related to the bucket and the respective attitudes of 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 respective measurement values of a reference point of an arm and the reference point of the bucket, the respective measurement values being measured using an external measurement device;
• a working equipment parameter acquiring unit configured to acquire the working equipment parameters related to the arm and the bucket, the working equipment parameters being used by the estimated position calculating unit;
• a calibration unit configured to calibrate the working equipment parameters related to the arm and the bucket based on the respective measurement values of the reference points of the arm and the bucket acquired by the measurement value acquiring unit;
• and
• a calibration range selecting unit configured to select, from among a first range where a variation in a swing angle of the bucket has a predetermined relationship with a change in the swing angle information detected by the swing angle detector and a second range where a variation in the swing angle increases as compared with the variation in the second range, the first range as a calibration range.

A working equipment parameter calibration method for a work machine, the work machine comprising:

• a first actuation unit;
• a bucket swingably connected to the first actuation unit;
• a hydraulic cylinder swingably connected to the first actuation unit to actuate the bucket;
• a first link member having a first end rotatably connected to a distal end of the hydraulic cylinder and a second end rotatably connected to the first actuation unit;
• a second link member having a first end rotatably connected to a distal end of the hydraulic cylinder and a second end rotatably connected to the bucket;
• a swing angle detector configured to detect swing angle information of the bucket relative to the first actuation unit;
• an attitude calculating unit configured to calculate respective attitudes of the first actuation unit and the bucket based on the detected swing angle information of the bucket;
• and
• an estimated position calculating unit configured to calculate an estimated position of a reference point of the bucket based on a working equipment parameter related to a member of the first actuation unit, a working equipment parameter related to the bucket and the respective attitudes of the first actuation unit and the bucket calculated by the attitude calculating unit, the calibration method being performed in the work machine, the calibration method comprising:
• acquiring respective measurement positions of a reference point of the first actuation unit and the reference point of the bucket, the respective measurement positions being measured using an external measurement device;
• defining a first range where a variation in a swing angle of the bucket has a predetermined relationship with a change in the swing angle information detected by the swing angle detector and a second range where a variation in the swing angle increases as compared with the variation in the first range;
• selecting the first range as a calibration range;
• and
• calibrating the working equipment parameter related to the bucket based on the measurement values measured using the external measurement device in the selected first range.