Travel control system for construction machinery and travel control method for construction machinery

A travel control system for construction machinery, comprising:

• first and second hydraulic pumps;
• a first travel motor operable by a working oil discharged from the first hydraulic pump;
• a second travel motor operable by the working oil discharged from the first hydraulic pump or the second hydraulic pump;
• at least one actuator operable by the working oil discharged from the first hydraulic pump or the second hydraulic pump;
• a straight travel valve to be switched between a first position and a second position, wherein the straight travel valve is switched to the first position such that the working oil discharged from the first hydraulic pump is supplied to the first travel motor and the working oil discharged from the second hydraulic pump is supplied to the second travel motor, and the straight travel valve is switched to the second position such that the working oil discharged from the first hydraulic pump is supplied to the first and second travel motors and the working oil discharged from the second hydraulic pump is supplied to the actuator;
• first and second travel motor control valves configured to control amounts of the working oil supplied to the first and second travel motors according to a displacement amount of a spool therein respectively;
• first and second spool displacement adjusting valves supplying pilot signal pressures to the spools of the first and second travel motor control valves respectively in proportion to an inputted control signal to control the displacement amounts of the spools of the first and second travel motor control valves;
• and
• a controller configured to output the control signal to each of the first and second spool displacement adjusting valves corresponding to a manipulation signal of an operator, and configured to adjust the displacement amounts of the spools of the first and second travel motor control valves to be limited according to a manipulation signal of the actuator when the manipulation signal of the actuator is received during a travelling operation of the first and second travel motors,
• wherein the controller comprises:
• a calculator calculating the amounts of the working oil to be supplied to the first and second travel motors from an inputted travel manipulation signal for the first and second travel motors and the inputted manipulation signal of the actuator;
• a pedal displacement converter converting an inputted pedal displacement amount for the first and second motors into a secondary pedal displacement amount corresponding to the calculated working oil amount;
• and
• an output portion outputting the control signal for controlling the pilot signal pressure in proportion to the secondary pedal displacement amount.