Failure diagnosis device and failure diagnosis method

A failure diagnosis device for a mechanical device provided with a motor as a source to drive a motion axis, and configured to acquire a moving position of the motion axis and a disturbance torque value applied to the motion axis every predetermined period, and to diagnose that a failure is occurring when the disturbance torque value is larger than a failure determination threshold, comprising:

• a disturbance torque selector configured to calculate a change from a reference value of each of the acquired disturbance torque values, and to accumulate the disturbance torque values except each disturbance torque value having the change from the reference value equal to or larger than a predetermined threshold;
• and
• a failure diagnosis unit configured to diagnose a failure of the mechanical device by using the disturbance torque values accumulated by the disturbance torque selector,
• wherein the disturbance torque selector calculates a rate of change with respect to the reference value as the change from the reference value.

A failure diagnosis method for a mechanical device provided with a motor as a source to drive a motion axis, and designed to acquire a moving position of the motion axis and a disturbance torque value applied to the motion axis every predetermined period, and to diagnose that a failure is occurring when the disturbance torque value is larger than a failure determination threshold, the method comprising:

• calculating, via a failure diagnosis device, a change from a reference value of each of the acquired disturbance torque values, and accumulates the disturbance torque values except each disturbance torque value having the change from the reference value equal to or larger than a predetermined threshold;
• and
• diagnosing, via the failure diagnosis device, a failure of the mechanical device by using the accumulated disturbance torque values, and
• calculating, via the failure diagnosis device, a rate of change with respect to the reference value as the change from the reference value.