As is known, servo motors are equipment used for precise positioning, and the part that provides precise positioning is the encoder. Motion profiles are performed with the PID control method generally. However, in some cases, the values in the Proportional, Integral, or Derivative definitions that provide the PID are not compatible with the system. This is the main reason why the servo motor buzzes loudly at a stop or while moving. As can be seen in the example in the video below, the servo motor is in the “on” state, but a loud humming sound is heard when it is stationary.
This is because the values coming to the PID take into account very high or very low range values when scaling the positioning. The easiest way to fix is to listen to the run sound after changing the proportional gain value. Of course, servo controllers with auto-tuning settings may not need to be adjusted manually. Changing the proportional gain value to reduce the sound can affect motion performance. For such cases, two different gain settings as “active” and “holding” can be entered in some servo motor drivers. While using the “active” settings, which react faster when the system is activated, “holding” settings are used to prevent humming in the stopped position.
Sometimes we have seen the system humming or making loud noises only when it moves. Based on our mechanical experience, we can say that such problems are caused by the coupling connections. Since the two parts of the coupling are not in the same axial plane, the metal parts rub against each other and may sound like a problem with the PID setting.