Leveling control system and method for heavy equipment

• US 8,195,367 B2
• Filed: 12/02/2008
• Issued: 06/05/2012
• Est. Priority Date: 12/12/2007
• Status: Expired due to Fees

• Current Assignee: Volvo Construction Equipment Holding Sweden AB
• Original Assignee: Volvo Construction Equipment Holding Sweden AB
• Inventors: Kim, Jin Seop, Lee, Chang Soo, Kim, In Woo
• Primary Examiner(s): Novosad, Christopher J.
• Application Number:
  US12/326,375
• Publication Number:
  US 20090151483A1
• Time in Patent Office: 1,281 Days
• Field of Search: 701/50, 404/85, 404/90, 180/209, 280/43, 280/43.24, 37411-417, 379/07, 172 1- 12, 414/680, 414696-706
• US Class Current: 701/50
• CPC Class Codes: B60G 2300/09 Construction vehicles, e.g. graders, excavators
• CPC Class Codes: B62D 33/063 movable from one position into at least one other position, e.g. tiltable, pivotable about a vertical axis, displaceable from one side of the vehicle to the other
• CPC Class Codes: B62D 55/116 Attitude or position control of chassis by action on suspension, e.g. to compensate for a slope
• CPC Class Codes: G05D 1/0891 specially adapted for land vehicles
• CPC Class Codes: Y10S 37/907 Automatic leveling excavators
• CPC Class Codes: Y10T 74/11 Tripping mechanism
• CPC Class Codes: Y10T 74/111 Speed controlled

Abstract

A leveling control system and method for heavy equipment, in which a lower frame having a traveling unit and an upper frame are combined together by a tilting unit. The system includes a sensor unit, provided in the equipment, for measuring twist angles of the lower frame and the upper frame against a reference horizontal surface and a traveling speed of the equipment, and detecting working state information of working devices; a control unit for receiving the twist angles, the traveling speed, and the working state information, calculating a correction angle for the leveling control of the upper frame, and generating a control signal for instructing an operation of an actuator in accordance with the correction angle; and a driving unit for performing the leveling through the actuator in accordance with the control signal received therein. The control unit is provided with an auto leveling mode module for performing the leveling against a reference horizontal surface, a re-leveling mode module for performing the leveling against the reference horizontal surface in a standstill state of the equipment for a limited time, and a track leveling mode module for performing the leveling against the lower frame.

Claims

1. A leveling control system for controlling automatic leveling of heavy equipment with a lower frame and an upper frame, the lower frame having traveling means, and the upper frame tiltably and swingably connected to the lower frame, the leveling control system comprising:

a sensor unit, provided in the equipment, for measuring twist angles of the lower frame and the upper frame against a reference horizontal surface and a traveling speed of the equipment, and detecting working state information of working devices;

a control unit for receiving the twist angles, the traveling speed, and the working state information, calculating a correction angle for the leveling control of the upper frame, and generating a control signal for instructing an operation of an actuator in accordance with the correction angle, the control unit including an auto leveling mode module for performing the leveling against a reference horizontal surface, a re-leveling mode module for performing the leveling against the reference horizontal surface in a standstill state of the equipment for a limited time, and a track leveling mode module for performing the leveling against the lower frame; and

a driving unit for performing the leveling through the actuator in accordance with the control signal received therein;

wherein the control unit comprises;

a receiving module for receiving the twist angles against a reference horizontal surface, the traveling speed, and the working state information from the sensor unit;

a correction angle calculation module for setting the twist angle of the upper swing structure as a first twist angle, and calculating the correction angle, at which the upper swing structure is to be rotated, based on the first twist angle;

a control signal generation module for generating the control signal in accordance with a region, in which the actuator is to be operated, based on the correction angle;

an output module for transmitting the control signal to the driving unit;

a time limit module for counting an operation time in a standstill state of the lower frame, comparing the counted operation time with a predetermined reference operation time, and terminating the leveling control if the operation time is more than the reference operation time; and

a display signal generation module for generating a display signal for displaying the twist angles of the lower frame and the upper swing structure through a display unit provided with an image display device.

2. The system of claim 1, wherein the control unit further comprises an emergency stop module for immediately terminating the leveling control if an emergency stop condition is satisfied in the auto leveling mode, the re-leveling mode, or the track leveling mode.

3. The system of claim 1, wherein, if the auto leveling mode or the re-leveling mode is activated, the correction angle calculation module calculates the correction by calculating “

twist angle of lower frame−

maximum allowable lower limit twist angle range−

first twist angle”

in the case where the reference angle is “

reference angle<

twist angle of lower frame−

maximum allowable lower limit twist angle range”

;

calculating “

reference angle−

first twist angle”

in the case where the reference angle is “

twist angle of lower frame−

maximum allowable lower limit twist angle range≦

reference angle≦

twist angle of lower frame+maximum allowable upper limit twist angle range”

; and

calculating “

twist angle of lower frame+maximum allowable upper limit twist angle range−

first twist angle”

in the case where the reference angle is “

twist angle of lower frame+maximum allowable upper limit twist angle range<

first twist angle”

.

4. The system of claim 1, wherein the correction angle is calculated by calculating “

twist angle of lower frame−

first twist angle”

through the correction angle calculation module if the track leveling mode is activated.

5. The system of claim 4, wherein the correction angle is calculated by calculating “

twist angle of lower frame+weight angle−

first twist angle”

if the weight angle is set.

6. The system of claim 1, wherein, in the auto leveling mode or the re-leveling mode, the control signal is generated by the control signal generation module in a manner that, if the first twist angle is within a marginal convergence range or within a reference convergence range, a second control signal for operating the actuator at low speed is generated, and if the first twist angle is out of the marginal convergence range and the reference convergence range, a first signal that does not limit the operation speed of the actuator is generated;

and

wherein the marginal convergence range is calculated through “

twist angle of lower frame−

maximum allowable lower limit twist angle range marginal convergence range≦

twist angle of lower frame−

maximum allowable lower limit twist angle range+constant angle”

or “

twist angle of lower frame+maximum allowable upper limit twist angle range−

constant angle≦

marginal convergence range≦

twist angle of lower frame+maximum allowable upper limit twist angle range”

; and

the reference convergence range is calculated through “

reference angle−

constant angle reference convergence angle reference angle+constant angle”

.

7. The system of claim 1, wherein, in the track leveling mode, the control signal is generated by the control signal generation module in a manner that, if the first twist angle is within a speed convergence range, a second control signal for operating the actuator at low speed is generated, and if the first twist angle is out of the speed convergence range, a first control signal that does not limit the operation speed of the actuator is generated;

and

wherein the speed convergence range is calculated through “

twist angle of lower frame−

constant angle speed convergence range twist angle of lower frame+constant angle”

.