Abnormality detection device which detects abnormalities in power transmission mechanism for transmitting rotational force outputted by motor

An abnormality detection device for detecting an abnormality in a power transmission mechanism that transmits a rotational force output by an electric motor, comprising:

• a first rotational position detector for detecting a rotation angle of an input shaft of the power transmission mechanism;
• a second rotational position detector for detecting a rotation angle of an output shaft of the power transmission mechanism;
• an operation control unit for controlling an operation of the electric motor;
• and
• a detection unit for detecting an abnormality in the power transmission mechanism based on the output of the first rotational position detector and the output of the second rotational position detector, wherein
• the operation control unit controls the electric motor so that the position obtained from the output of the second rotational position detector corresponds to the position defined in an operation program, and
• the detection unit includes:
• a variable setting unit for setting a variable including an angular difference that is a difference between the rotation angle obtained from the output of the first rotational position detector and the rotation angle obtained from the output of the second rotational position detector, based on the output of the first rotational position detector, the output of the second rotational position detector, and a reduction ratio of the power transmission mechanism;
• and a determination unit for determining whether the power transmission mechanism is abnormal, based on the variable.