TECHNICAL SUPPORT
Published 2026-02-22
It is too common to get stuck on the choice ofservowhen engaging in product innovation. Especially when it comes to the core parameter "server pulling force", if you don't know it clearly, the project progress will be stuck every minute. Many friends asked me with the drawings: "Can this structure of mine move?" In fact, most of the problems lie in the understanding ofthe pulling force of the steering gear. To put it bluntly, the steering gear is just a small motor. Its pulling force determines how many things it can pull. This is the power source of the entire motion mechanism. If the source is not selected correctly, all the subsequent efforts will be in vain.
You may be thinking, the worst thing is that you can’t move? The reality is much more complicated than that. Imagine that you are happy to install the product. As soon as the power is turned on, the robotic arm shakes twice and then stops, or it is unable to lift it halfway up. This is a typical "little horse and big cart". What's even more troublesome is that sometimes it doesn't move completely, but its movements are stuck, its response is slow, and it even makes a harsh "hissing" sound. This is not only a functional failure, but also accelerates gear wear. It won’t take long for the steering gear to be completely scrapped. It's like a person carrying a burden. He can only carry 50 kilograms, but you have to let him carry 100 kilograms. He will fall down after taking two steps.
Many friends stared at "torque" as soon as they came up. What is kg·cm? They were confused. Don't be intimidated by these professional terms, just understand it as "strength". The "xx kg·cm" on theservoparameter table means that theservoarm length is 1 cm and can pull xx kg. This is a conversion standard to facilitate horizontal comparison. For example, for a 20kg·cm servo, if my servo arm is 2cm, then the actual weight it can pull will be doubled and become 10kg. This conversion relationship is the first key point in model selection and directly determines your structural design.
I have to pour some cold water on you here. Never take the nominal pulling force as the actual limit value that can be used. The parameters given by the manufacturer are usually measured in the most ideal and perfect laboratory environment. In practical applications, whether your power supply voltage is stable, whether the gear precision of the steering gear itself is high, or even whether the weather is cold or not will affect its "strength". The most important thing is that you have to leave a "safety margin" for the pulling force. It is generally recommended that the actual pulling force should not exceed 70% to 80% of the nominal value. It's like buying a car. The manual says it can run 200 yards, but if you drive so fast every day, the car and people can't stand it.
There are routines for calculating actual demand. The first step is to calculate the weight and resistance of the driven part of the structure. This includes its own weight, friction, and if it involves lifting the head, the gravity component is also included. Don't just rely on your feelings to estimate. Use a spring scale to pull it, or use software to build a model and analyze it. The more accurate the data, the smaller the risk will be later. ️ For example, if you want a robotic arm to lift a 500-gram camera, but the friction on the shaft is not small, and the movement speed is required to be fast, the actual force required may be several kilograms. After calculating this clearly, you can go to the parameter table to find the corresponding servo.
After determining the approximate number of kilograms required, you will find that there are still many options on the market. At this time, it is necessary to screen from several dimensions. The first is to look at the brand's reputation, especially those bloggers who makeservo pulltest videos. Their actual measurement data is more reliable than the official promotional page. Secondly, look at the gear material. The strength and durability of metal gears are definitely better than plastic ones, and they can withstand greater pulling force. In addition, don’t forget to look at the control panel. A good control panel can make the servo respond faster and move more accurately, which is also the guarantee that the “power” can be fully exerted. You get what you pay for, which is basically applicable in this field.
Sometimes the project schedule is tight, or the right steering gear cannot be found due to space and cost constraints. At this time, you have to use your brains on the structure. A very effective method is to adjust the length of the servo arm. According to the lever principle, the shorter the arm, the greater the pulling force it can output, but the price is that the movement stroke will become smaller. vice versa. It's a trade-off. In addition, adding bearings to the motion mechanism and using smoother materials can greatly reduce friction and increase the "effective pulling force" of the steering gear in disguise. It's like putting a few drops of oil on a rusty door shaft. It couldn't be pushed at first, but now it opens with a light touch. These little tricks can often save you a lot of trouble.
After seeing this, you should have an idea aboutthe steering gear pulling force. But I want to ask you a very practical question: in the servo product introduction pages or evaluation videos you have seen, do you think there is a big gap between the pulling force data marked on them and the actual feeling of using it? Welcome to chat about your experience in the comment area. If you think this article is helpful to you, don’t forget to give it a like or share it with friends who are currently working on projects. If you want to know more about steering gear selection, you can search our company's official website, which has a more systematic introduction.
Update Time：2026-02-22
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