Control system for construction machinery

1. A control system for construction machinery, comprising:

a main control valve installed in a hydraulic line between a hydraulic pump and actuators, and including a first group of electro proportional pressure reducing valves outputting a first secondary pressure in proportion to a first pressure command signal to a first spool for controlling a first group of actuators of the actuators, and a second group of electro proportional pressure reducing valves outputting a second secondary pressure in proportion to a second pressure command signal to a second spool for controlling a second group of actuators of the actuators;

a safety lever valve installed in a pilot line through which a pilot working fluid discharged from a pilot pump is supplied and configured to selectively open and close the pilot line;

a first control valve installed in a first control line through which the pilot working fluid is supplied to the first group of electro proportional pressure reducing valves and configured to selectively open and close the first control line, the first control line being connected to the safety lever valve;

a second control valve installed in a second control line through which the pilot working fluid is supplied to the second group of electro proportional pressure reducing valves and configured to selectively open and close the second control line, the second control line being connected to the safety lever valve;

a first pressure sensor configured to detect the first secondary pressure outputted from the first group of electro proportional pressure reducing valves and a second pressure sensor configured to detect the second secondary pressure outputted from the second group of electro proportional pressure reducing valves; and

a controller configured to output the first and second pressure command signals to the first and second groups of electro proportional pressure reducing valves corresponding to a manipulation signal of the construction machinery, and configured to compare the first and second secondary pressures detected by the first and second pressure sensors and the first and second pressure command signals to determine whether or not the first and second groups of electro proportional pressure reducing valves fail,

wherein when it is determined that any one of the first group of electro proportional pressure reducing valves fails, the controller closes the first control valve to block the pilot working fluid from being supplied to the first group of electro proportional pressure reducing valves, and when it is determined that any one of the second group of electro proportional pressure reducing valves fails, the controller closes the second control valve to block the pilot working fluid from being supplied to the second group of electro proportional pressure reducing valves,

wherein the safety lever valve is configured to be closed based upon a manipulation of a safety lever or push of an engine emergency stop button in a cabin, to block the supply of the pilot working fluid through the pilot line, and

wherein the first group of actuators comprises at least one of a right traveling hydraulic motor, a left traveling hydraulic motor and a swing motor, and the second group of actuators comprises at least one of a boom cylinder, an arm cylinder and a bucket cylinder.

2. The control system for construction machinery of claim 1 , wherein at least one of the first and second control valves includes a solenoid valve.

3. The control system for construction machinery of claim 1 , wherein the controller comprises

a first controller configured to compare the first secondary pressure detected by the first pressure sensor and the first pressure command signal inputted to the first group of the electro proportional pressure reducing valves to determine whether or not the first group of electro proportional pressure reducing valves fail; and

a second controller configured to compare the second secondary pressure detected by the second pressure sensor and the second pressure command signal inputted to the second group of the electro proportional pressure reducing valves to determine whether or not the second group of electro proportional pressure reducing valves fail.

4. The control system for construction machinery of claim 3 , wherein when it is determined that any one of the first group of electro proportional pressure reducing valves fails, the first controller generates a first block signal for blocking the pilot working fluid from being supplied to the first group of electro proportional pressure reducing valves, and

when it is determined that any one of the second group of electro proportional pressure reducing valves fails, the second controller generates a second block signal for blocking the pilot working fluid from being supplied to the second group of electro proportional pressure reducing valves.

5. A control system for construction machinery, comprising:

a main control valve installed in a hydraulic line between a hydraulic pump and actuators, and including a first group of electro proportional pressure reducing valves outputting a first secondary pressure in proportion to a first pressure command signal to a first spool for controlling a first group of actuators of the actuators, and a second group of electro proportional pressure reducing valves outputting a second secondary pressure in proportion to a second pressure command signal to a second spool for controlling a second group of actuators of the actuators;

a safety lever valve installed in a pilot line through which a pilot working fluid discharged from a pilot pump is supplied and configured to selectively open and close the pilot line;

a first control valve installed in a first control line through which the pilot working fluid is supplied to the first group of electro proportional pressure reducing valves and configured to selectively open and close the first control line, the first control line being connected to the safety lever valve;

a second control valve installed in a second control line through which the pilot working fluid is supplied to the second group of electro proportional pressure reducing valves and configured to selectively open and close the second control line, the second control line being connected to the safety lever valve;

a first pressure sensor configured to detect the first secondary pressure outputted from the first group of electro proportional pressure reducing valves and a second pressure sensor configured to detect the second secondary pressure outputted from the second group of electro proportional pressure reducing valves; and

a controller configured to output the first and second pressure command signals to the first and second groups of electro proportional pressure reducing valves corresponding to a manipulation signal of the construction machinery, and configured to compare the first and second secondary pressures detected by the first and second pressure sensors and the first and second pressure command signals to determine whether or not the first and second groups of electro proportional pressure reducing valves fail,

wherein when it is determined that any one of the first group of electro proportional pressure reducing valves fails, the controller closes the first control valve to block the pilot working fluid from being supplied to the first group of electro proportional pressure reducing valves, and when it is determined that any one of the second group of electro proportional pressure reducing valves fails, the controller closes the second control valve to block the pilot working fluid from being supplied to the second group of electro proportional pressure reducing valves,

wherein the safety lever valve is configured to be closed based upon a manipulation of a safety lever or push of an engine emergency stop button in a cabin, to block the supply of the pilot working fluid through the pilot line, and

wherein the main control valve further comprises a hydraulic control valve having a third spool for controlling a third group of actuators of the actuators, the third spool being controlled by a pilot pressure in proportion to a manipulation amount of a manipulation lever.