TECHNICAL SUPPORT
Published 2026-03-24
When doing product innovation, have you ever encountered this situation: after you bought theservo, you found that it could not be installed at all, or that the movement seemed laggy or even inoperable after it was installed? You know, once you choose the wrongservo, it is very likely that the entire project will have to be overturned, which will consume time and money.
Let’s talk aboutservos in depth today, starting from the selection of servos to subsequent maintenance. We will explain the common problems clearly at once to help you avoid detours in related operations.
When choosing a servo, the first step is to look at the torque. This is like choosing car tires, they must match the weight of the car. First, you need to estimate how much force the mechanism you are using requires. For example, if it is a robot arm, you need to know how many items it needs to lift, and then choose a servo with at least 30% torque margin. Don't be greedy for cheap and choose the one that is just enough, because the power required at the moment of startup is often much more strenuous than during normal operation.
The second step depends on the size and mounting hole location. Many people tend to overlook this point, and when they buy it, they find that it cannot fit into the case at all. The most reliable way is to first download the 2D drawing of the servo, and then compare it with your structural design to carefully confirm the screw hole spacing and the shape of the output shaft, and make sure it fits perfectly.
The servo usually has three wires, the red wire represents the positive pole of the power supply, the black or brown wire is the ground wire, and the yellow or white wire is the signal wire. When connecting, this order must not be reversed, especially if the positive and negative poles of the power supply are reversed, the servo will be burned out in an instant. The power supply voltage must be operated strictly in accordance with the instructions. If the nominal voltage of the servo is 6V, then don't think about connecting it to 7.4V to try it, otherwise it will not bring surprises, but shock. The signal line needs to be connected to the PWM output port of the controller.
There is a common problem here: many people forget the key point of common ground, that is, they do not connect the GND of the controller and the GND of the servo, which ultimately leads to signal drift and random jitter of the servo. Please remember that the ground wire must be connected, so that the servo can work normally and stably.
The steering gear relies on the PWM signal to control the angle. In short, it uses the width of the pulse to convey the rotational position information to it. In a standard servo, a pulse of 0.5 milliseconds corresponds to 0 degrees, a pulse of 2.5 milliseconds corresponds to 180 degrees, and changes linearly between the two. When you write code, you might as well try it with the middle value of 1.5 milliseconds to see if the servo can rotate to 90 degrees, and then gradually fine-tune it.
If you want to achieve continuous rotation, you need to choose a special continuous rotation servo. It should be noted that this kind of servo cannot control precise angles. All it can control is speed and direction. Before making a selection, be sure to clearly define your needs: whether you need precise positioning or just continuous rotation of the servo, do not confuse these two needs.
When encountering a situation where the servo does not respond, do not rush to restart the system. The first step is to check the power supply. The current required by the steering gear at the moment of starting is very large, especially the steering gear with high torque. If the nominal current of your power adapter is not enough, the voltage will drop quickly when the servo is started, and the servo will naturally not respond in any way. At this time, you can replace it with a power supply with a larger current, or directly connect a large capacitor in parallel to the power line, which can make the voltage more stable.
The second step is to check the signal. If you have an oscilloscope, then directly check whether the PWM waveform is emitted; if you do not have an oscilloscope, you can write the simplest loop program to let the servo swing back and forth. At the same time, use a multimeter to measure the voltage of the signal line to see if there is a jump in the voltage. By separating hardware and software for troubleshooting, problems can be quickly located.
It is a common problem that the servo is in a false position, so how to solve it? This requires us to have a deep understanding of the causes of the steering gear's virtual position, and then take targeted and effective measures. First, check whether the installation of the servo is stable. If the installation is loose, it may cause a false position, so be sure to ensure that the servo is installed tightly and in an accurate position. Secondly, check whether the transmission parts of the steering gear, such as gears, etc., are worn or damaged. If so, the damaged parts need to be replaced in time. In addition, you need to pay attention to whether the control signal of the steering gear is normal. Instability of the signal may also cause the problem of false position. Carefully check whether there are faults in the signal transmission line, etc. Only through comprehensive and detailed inspection and processing can the problem of the steering gear's empty position be effectively solved and the steering gear returned to normal and stable working condition.
The virtual position refers to the gap where the output shaft of the servo can shake slightly when it stops at a certain angle. In some application scenarios that require extremely high precision, such as when a robotic arm grabs an object or a camera gimbal stabilizes the image, excessive virtual position will make people crazy. Therefore, when choosing a steering gear, you should give priority to those equipped with metal gears and double bearings. Steering gears with this type of structure can usually control the virtual position very well. If the purchased servo has a virtual position problem, it can be compensated in terms of the control algorithm. For example, each movement will gradually approach the target angle from the same direction, and the excess shaking can be eliminated by using the gap between gear bites. Of course, the most worry-free way is to check the "return clearance" in the parameter table before purchasing and choose a servo with a smaller value.
The steering gear is a precision mechanical component and is extremely afraid of dust and impact. If your equipment is operated in dusty environments such as carpentry rooms and construction sites, it is best to add a dust cover to the servo. Even just putting a plastic bag on it and tightening it is far better than leaving the servo in a streaking state. Pay attention to the sound when using the equipment. If there is rattling or sluggish operation, the gears need to be disassembled and inspected. For metal gears, you can add a little grease every six months, but plastic gears should not be added at will because they are prone to corrosion.
When storing the servo, avoid areas with high temperature and humidity. If it is not used for a long time, power it on every one or two months and let it rotate a few times to prevent the grease inside from solidifying and causing it to get stuck.
In what scenarios are you going to use the servo for your next innovative product? Have you encountered any difficult situations during the selection or debugging process? Welcome to share in the comment area. Let's accumulate valuable experience together and help newcomers to minimize unnecessary detours.
Update Time：2026-03-24
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