YASKAWA's Now
When a servo motor is used to determine the positioning of machinery such as machine tools and manufacturing equipments of semiconductors and electronic parts, and the vibration is caused by the stop movement of the motor, the machines cannot move on to the next movement until the vibration stops, resulting in longer machine operating time. If vibration caused by the motor stop for positioning can be controlled, the machine operating time can be shortened.
This time, we would like to introduce the Vibration Control Function which is used when a servo motor stops after the positioning.
About vibration
When a motor stops the machine moving part, the whole machine is vibrated (shaken) as a reaction in some cases at a low frequency of a few ten Hertz. The larger the deceleration to a stop is, the greater the vibration amplitude becomes. If the machine structure is made thin to make the machine smaller in size or lighter in weight, the vibration also becomes larger since the rigidity of the moving part is relatively lowered.
Such vibration can displace the moving part from its intended stop position and can lose the positioning stability
Generating vibration
To generate simulated vibration, the following machine model is used.
This model is equipped with an arm and weight installed onto the movable table of linear slider (linear motor). A servo driver moves the movable table and vibration of the weight is measured when the movable table is stopped at a position designated by a reference.
Vibration control
When the same machine model is operated with the Vibration Control Function, the model does not vibrate almost at all at the motor stop, as shown below.
The Vibration Control Function can control vibration by detecting actual vibration frequency and removing the frequency component. YASKAWA's servo driver detects whether vibration has been generated or not and, if generated, detects accurate vibration frequency. In many cases, the vibration amplitude fluctuates greatly and becomes unstable when the vibration is half-stopped like a waveform in condition without vibration control function. Even in such condition, the vibration frequency can be accurately detected with our unique method.
Effects of Vibration Control Function
For example, when an arm end of the aforementioned machine model is used for a handling work, you need to wait until the arm end vibration stops. This waiting time of vibration stop is wasteful and deteriorates the work efficiency. With the Vibration Control Function, the vibration generated at motor stop can be controlled to improve the machine productivity. Since servo motors are used widely for machine tools, manufacturing equipments of semiconductors and electronic parts and robots, YASKAWA's
