Malfunction-type determination device and malfunction-type determination method

A malfunction-type determination method of a malfunction-type determination device configured to determine a type of a malfunction of an apparatus including a rotating mechanism, the method comprising:

• detecting a driving force in the rotating mechanism;
• detecting vibrations in the apparatus;
• calculating a first average of values in a first period, and calculating a second average of values in a second period after the first period for each of the detected driving forces and the detected vibrations;
• calculating a quotient of the second average and the first average,
• comparing the quotient with a first preset value and a second preset value to detect whether an inclination of a change in each of the detected driving forces and the detected vibrations with a lapse of time indicates an inclination toward an increase, an inclination toward a decrease, or no inclination toward the increase or decrease,
• determining that the detected driving forces or vibrations show no inclination toward either the increase or the decrease when the quotient is greater than or equal to the first preset value and less than or equal to the second preset value,
• determining that the detected driving forces or vibrations show an inclination toward the increase when the quotient is greater than the second preset value,
• determining that the detected driving forces or vibrations show an inclination toward the decrease when the quotient is smaller than the first preset value, and
• determining the type of the malfunction of the apparatus in accordance with a combination of the inclination of the change in each of the detected driving forces and the detected vibrations with a lapse of time,
• wherein the first preset value is a value obtained by subtracting a predetermined value from 1, and the second preset value is a value obtained by adding the predetermined value to 1.