Anomaly detection method and motor control device

• US 20070188117A1
• Filed: 06/29/2005
• Published: 08/16/2007
• Est. Priority Date: 06/29/2004
• Status: Active Grant

• Current Assignee: THK Company Limited
• Original Assignee: THK Company Limited
• Inventors: Shoda, Kazuo, Nomura, Yuki, Nagato, Yoshifumi
• Granted Patent: US 7,439,693 B2
• Time in Patent Office: Days
• US Class Current: 318/135
• CPC Class Codes: H02H 7/0856 characterised by the protection measure taken
• CPC Class Codes: H02P 25/06 Linear motors

Abstract

A control unit of a motor driver performs feedback control to supply current to a linear motor based on a detection value of a linear encoder. An anomaly detection unit monitors the supply current to the linear motor, and the anomaly detection unit detects anomaly of a linear motion apparatus based on a waveform of the supply current. In the case where the anomaly is detected, a user is notified of warning by means of a lamp, a buzzer, an e-mail, and the like. Therefore, the anomaly of the linear motion apparatus can be detected early and accurately.

Claims

1. A linear motion apparatus anomaly detection method of detecting anomaly of a linear motion apparatus based on a waveform of supply current or supply voltage to a motor which drives the linear motion apparatus.

2. A linear motion apparatus anomaly detection method, wherein a motor control device of a motor which drives a movable body of a linear motion apparatus, executes the steps of:

detecting a position or a speed of the movable body;

performing feedback control to supply current or supply voltage to the motor based on the detection result; and

detecting anomaly of the linear motion apparatus based on an abnormal signal component included in a waveform of the supply current or the supply voltage.

3. A linear motion apparatus anomaly detection method according to claim 2, wherein the motor control device further executes the steps of:

extracting the abnormal signal component which is superposed on a normal signal from the waveform of the supply current or supply voltage; and

judging that the anomaly is generated in the linear motion apparatus when the abnormal signal component satisfies a predetermined condition.

4. A motor control device that controls a motor for driving a movable body of a linear motion apparatus, the motor control device comprising:

position detection means for detecting a position or a speed of the movable body;

control means for performing feedback control to supply current or supply voltage to the motor based on the result detected by the position detection means; and

anomaly detection means for detecting anomaly of the linear motion apparatus based on an abnormal signal component included in a waveform of the supply current or supply voltage.

5. A motor control device according to claim 4, wherein the anomaly detection means includes:

a sensor that performs waveform input of the supply current or supply voltage;

a filter circuit that extracts the abnormal signal component from the inputted waveform; and

a comparison circuit that compares the extracted abnormal signal component and a predetermined condition.