Refrigerator with automatic door and method for controlling automatic door of refrigerator

A refrigerator comprising:

• a main body including an inner case defining a storage container, an outer case surrounding the inner case, and an insulator disposed between the inner case and the outer case;
• a door rotatably coupled to the main body and configured to open and close the storage container;
• a door driver disposed at an upper portion of the main body and configured to, based on the door being pressed, open the door;
• a sensor comprising a magnetic field sensor and a magnet and configured to detect an open or closed state of the door and measure a pressed amount of the door based on a change in a distance between the magnetic field sensor and the magnet;
• and
• a controller configured to control the door driver and determine whether the door is to be opened based on the pressed amount of the door,
• wherein the controller is configured to:
• select, as a threshold value, an output voltage of the magnetic field sensor based on the door being closed,
• calculate an operation determination value based on an equation that obtains the operation determination value by multiplying a slope by a sum of the threshold value and a quotient of a y-intercept divided by the slope, the slope being a positive number less than 1 and denoting operation determination value change amount/threshold value change amount, and the y-intercept being a negative number and denoting a point where a y-axis representing the operation determination value meets a straight line of the equation,
• compare the operation determination value with a preset operation determination lower limit,
• substitute, based on the calculated operation determination value being less than the operation determination lower limit, the operation determination value with the operation determination lower limit, and
• determine whether the door is to be opened by comparing (i) a difference between the output voltage and the threshold value with (ii) the substituted operation determination value, and
• wherein the difference between the output voltage and the threshold value is compared with the operation determination value to determine, based on the operation determination value being equal to or greater than the operation determination lower limit, whether the door is to be opened.