TECHNICAL SUPPORT
Published 2026-02-28
Friends who play withservos, nine out of ten times have encountered this troublesome thing: they happily connected the newly purchasedservoto the power supply, but before it could start moving, it trembled on its own, accompanied by the sound of "buzzing" electricity. What the hell is going on? Is theservobroken, or am I doing something wrong? Don't worry, today we will talk about the annoying problem of servo vibration when power is turned on, and see what secrets are hidden behind it, and how to "subdue" it.
Many friends who are new to servos get upset when they see the servos vibrating, wondering if they have bought a defective product. In fact, slight jitter is normal within a certain range, especially those with analog servos. You can think of it as a very sensitive person, always fine-tuning himself to stand more firmly. There is a potentiometer inside the steering gear to detect the position. When it feels that there is a deviation in the position, it will drive the motor to correct it. But if this correction process is too frequent or excessive, it will become the jitter we see. So, don’t rush to conclusions yet, you have to see how much it shakes.
This is the most common cause of servo vibration, no other. When the servo is started and loaded, the current required is extremely large. If your power supply is insufficient or the wiring is too thin, the voltage will drop instantly. Think of the current as water in a water pipe. The steering gear is like a "big water user". Once the water pressure is insufficient, it will work intermittently. The solution is quite simple: replace the power supply with a more powerful one, or ensure that the power supply line is thick enough and shorten the power supply distance. If possible, directly connecting a large capacitor in parallel to both ends of the servo power supply can also effectively alleviate the instantaneous power shortage.
In addition, there are some other factors that may affect the steering gear. For example, whether the installation position of the servo is stable. If the installation is not firm, jitter may occur during operation. In addition, whether the mechanical structure connected to the servo is smooth or not, if there are problems such as jamming, it will also be fed back to the servo and cause jitter. Therefore, when troubleshooting the servo vibration problem, in addition to paying attention to the power supply and wiring, these aspects also need to be carefully checked.
If your power supply is in a stable state, but the servo still jitters, then there is a high probability that there is a problem on the signal line. Especially when you use PWM signals to control the servo, the long signal line is like an antenna, which can easily absorb the surrounding electromagnetic interference and mix it into the control signal. In this way, the command received by the servo will deviate to the left and then to the right. It is strange that there is no jitter. In response to this situation, the solution is to "put on protective clothing" for the signal lines. You can try to use a shielded wire and ground the shielding layer at one end.
In addition, connecting a resistor of several hundred ohms in parallel between the signal line and the ground line can also play a certain anti-interference role and make the signal purer.
If external power supply and interference are ruled out, the problem is likely to lie with the servo itself. The most common thing is that the potentiometer inside is worn or dusty. This is like having sand in a person's joints, and they will definitely not move smoothly. Wear of the potentiometer will lead to inaccurate position feedback, and the servo will constantly make incorrect corrections, causing jitter. In this case, if it is a cheap servo, it is more cost-effective to just replace it with a new one. If it is a more expensive servo, you can try to disassemble and clean the potentiometer, but be very careful, because it is very delicate inside, and it will be completely scrapped if you don't do it properly.
Don't forget to double check the signal source. Check your control board, flight controller or receiver to see if the PWM signals they emit are stable. Sometimes, the PWM update frequency written in the program is too fast, or there is a slight jump in the duty cycle calculation, causing the servo to be at a loss. You can use an oscilloscope to view the actual waveform. If there are burrs on the edge of the waveform or the width continues to change, then the problem lies at the source. At this time, you need to optimize the program to ensure that the PWM signal can be output stably, or add a little dead zone processing to the code to make the servo less sensitive to small-scale fluctuations.
In addition, when troubleshooting problems, you also need to check whether the hardware connection is stable. For example, whether the line between the control board and the flight controller is loose, whether the interface of the receiver is in good contact, etc. Because these hardware problems may also cause signal transmission abnormalities, thereby affecting the stability of the PWM signal. If there is a problem with the hardware connection, it must be repaired in time to ensure normal signal transmission and create good conditions for the stable operation of the steering gear.
Sometimes, the jitter is not entirely an electrical problem, but may also be mechanical. If the steering wheel of the servo is connected to a very tight mechanical structure, or the connecting rod is stuck by something, the servo will have to push hard in order to reach the target position, and severe vibration and noise may occur in the process. It's like your hands shaking when you push hard on a stuck door. Try to disconnect the servo from the mechanical structure and test whether the servo alone still shakes. If it stops shaking, the problem lies in the mechanical structure behind it. Oil what needs to be oiled and adjust what needs to be adjusted.
Most servo vibrations are inseparable from the three circles of "power supply", "interference" and "mechanical". According to the ideas I mentioned above, most problems can be solved step by step.
After talking so much, I wonder if you have encountered any particularly strange cases of servo vibration when you were actually working on the project? How did you get it done in the end? Welcome to share your "fighting" experience in the comment area, let's exchange and learn together! If you find the article useful, don’t forget to like and share it so that more friends who play servos can see it.
Update Time：2026-02-28
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