Control apparatus

Abstract

A control apparatus of the present invention comprising a control unit outputting a control signal controlling a servo motor and suppressing natural vibration of a controlled object including a motor and a machine driven by the motor while controlling the controlled object, comprising a frequency analysis unit analyzing a frequency component included in a torque command, an analysis control unit controlling the start or stopping of the frequency analysis unit, a detection unit detecting a natural frequency of the controlled object from an analysis result of the frequency analysis unit, a band rejection filter receiving as input the torque command, stripping the command of the natural frequency component, and outputting the resultant command to the motor through a current control unit and servo amplifier, and a filter characteristic setting unit setting the frequency to be stripped at the filter based on the natural frequency detected by the detection unit.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2007-174296 filed on July 2, 2007, the entire contents of which are hereby incorporated by reference into this application. technical field [0002] The present invention relates to a control device, and more particularly to a control device for controlling a control target including a motor and a machine driven by the motor while suppressing the natural vibration of the control target. Background technique [0003] Currently, in a machine tool having an electric motor, a control device for the electric motor is used. In particular, a control device that uses a servo motor as a motor for feedback control, in order to always make the difference between the command value and the actual value of position, speed, current, etc. to be zero, so it is necessary to accurately control the mechanical position or motor speed, etc., so It is widely used in general CNC machine tools and the like. [0004] On...

AI Technical Summary

Problems solved by technology

[0017] In addition, the reason is that, depending on the state of the controlled object, resonance based on the natural frequency does not occur, so even if the detection is performed, the natural frequency of the controlled object may not be detected

[0018] In addition, in the process of reducing the natural vibration of the controlled object, the controlled object may become unstable

As an example, when the correct natural frequency cannot be detected, the wrong natural frequency is detected, and the filter setting is changed, the controlled object becomes unstable.

As another example, even when the correct natural frequency is detected, when the natural frequency is close to the control frequency band, the filter removes part of the signal in the control frequency band, and the controlled object becomes unstable.

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