Work vehicle and data calibration method

Patent metadata

Field	Value
Publication number	US-10378563-B2
Application number	US-201615562919-A
Country	US
Kind code	B2
Filing date	Nov 9, 2016
Priority date	Nov 9, 2016
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A work vehicle includes a work implement, a valve adjusting a flow rate of a hydraulic oil operating the work implement, an electromagnetic proportional control valve generating a pilot pressure guided to the valve, a controller outputting a current to the electromagnetic proportional control valve, and a sensor for detecting an operation of the work implement. The controller increases stepwise a current value of a current output to the electromagnetic proportional control valve by repeating processing for temporarily lowering a current value of the current output to the electromagnetic proportional control valve and thereafter outputting to the electromagnetic proportional control valve, a current having a current value greater than the current value before lowering. The controller calibrates data for predicting an operation speed of the work implement based on a result of detection by the sensor at the time when the current value is increased stepwise.

First claim

The invention claimed is:

1. A work vehicle comprising:
a work implement;
a valve adjusting a flow rate of a hydraulic oil operating the work implement;
an electromagnetic proportional control valve generating a pilot pressure guided to the valve;
a controller outputting a current to the electromagnetic proportional control valve; and
a sensor for detecting an operation of the work implement,
the controller including
a storage unit storing data for predicting an operation speed of the work implement,
a current value control unit increasing stepwise a current value of a current output to the electromagnetic proportional control valve by repeating processing for temporarily lowering a current value of the current output to the electromagnetic proportional control valve and thereafter outputting to the electromagnetic proportional control valve, a current having a current value greater than the current value before lowering, and
a calibration unit calibrating the data based on a result of detection by the sensor when the current value is increased stepwise by the current value control unit.

2. The work vehicle according to claim 1 , wherein
the current value control unit increases stepwise the current value of the current output to the electromagnetic proportional control valve by repeating processing for temporarily lowering the current value of the current output to the electromagnetic proportional control valve to a predetermined value and thereafter outputting to the electromagnetic proportional control valve, a current having a current value greater than the current value before lowering.

3. The work vehicle according to claim 2 , wherein
the predetermined value is zero.

4. The work vehicle according to claim 1 , further comprising a specifying unit specifying the current value when the work implement starts operation based on a result of detection by the sensor, wherein
the calibration unit calibrates the data with the specified current value.

5. The work vehicle according to claim 4 , wherein
the current value control unit increases stepwise the current value of the current output to the electromagnetic proportional control valve in increments of a prescribed value, and
the specifying unit specifies a current value of the current when an operation speed of a cylinder operating the work implement per unit time exceeds a predetermined threshold value and sets a value smaller than the specified current value and not smaller than a current value smaller by the prescribed value than the specified current value as a current value when the work implement starts operation.

6. The work vehicle according to claim 5 , wherein
the specifying unit sets the current value smaller by the prescribed value than the specified current value as the current value when the work implement starts operation.

7. The work vehicle according to claim 5 , wherein
the data includes data defining relation between the pilot pressure and the operation speed of the cylinder.

8. The work vehicle according to claim 7 , wherein
the work implement includes a bucket which can perform a tilting operation by means of the cylinder, and
the data relates to a speed of the tilting operation.

9. The work vehicle according to claim 7 , wherein
the current value control unit predicts an operation speed of the work implement by using the data on condition that an operation mode of the work vehicle is set to a first operation mode and restricts the current value of the current output to the electromagnetic proportional control valve based on a result of prediction, and increases stepwise a current value of the current output to the electromagnetic proportional control valve on condition that the operation mode of the work vehicle is set to a second operation mode.

10. A data calibration method in a work vehicle in which a work implement is operated, the work vehicle including a valve adjusting a flow rate of a hydraulic oil operating the work implement, an electromagnetic proportional control valve generating a pilot pressure guided to the valve, a controller outputting a current to the electromagnetic proportional control valve, and a sensor for detecting an operation of the work implement, the data calibration method comprising:
increasing stepwise, by the controller, a current value of a current output to the electromagnetic proportional control valve by repeating processing for temporarily lowering a current value of the current output to the electromagnetic proportional control valve and thereafter outputting to the electromagnetic proportional control valve, a current having a current value greater than the current value before lowering; and
calibrating, by the controller, data for predicting an operation speed of the work implement based on a result of detection by the sensor when the current value increases stepwise.

Assignees

• Komatsu Mfg Co Ltd

Inventors

• Ishida Atsushi
• Fujii Yuto
• Iwamura Tsutomu
• Nishiguchi Haruki

Classifications

• E02F3/43

  Control of dipper or bucket position; Control of sequence of drive operations · CPC title

• E02F9/264

  Sensors and their calibration for indicating the position of the work tool · CPC title

• E02F9/2296

  Systems with a variable displacement pump · CPC title

• E02F9/2025 Primary

  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) · CPC title

• E02F9/2285 Primary

  Pilot-operated systems · CPC title