TECHNICAL SUPPORT
Published 2026-02-21
When engaging in product innovation, doesservoselection give you a headache? Faced with various parameters and models, which structure is most suitable for your project? Don’t worry, it’s not difficult to choose the right model once you understand the internal structure of theservo. Today we will take it apart and talk about it thoroughly.
Open the casing of a standardservo, and you will find that inside is actually a sophisticated micro-electromechanical system. There are several core components: DC motor, reduction gear set, control circuit board and position feedback device (usually a potentiometer). These little guys each perform their own duties and work closely together to allow the servo to rotate to the specified angle obediently.
You can think of it as a smaller version of a robot joint. The motor is responsible for generating power, but the speed is too fast and the force is too small, so a reduction gear set is needed to reduce the speed and increase the torque. The control circuit is the "brain", which receives your instructions and then uses the "sensory organ" of the potentiometer to confirm whether the position is in place, ultimately achieving precise control.
This is about the closed-loop control system of the steering gear. When you send a pulse signal to the servo, such as turning its output shaft to 90 degrees, the control circuit will start working immediately. It will always stare at the voltage of the potentiometer, and this voltage value represents the current actual position of the output shaft.
The control circuit will compare the voltage corresponding to the 90-degree position you want with the current voltage fed back by the potentiometer. If there is a gap, it will immediately drive the motor to rotate and drive the gear set. The motor will not stop until the output shaft reaches 90 degrees and the two voltage values are completely equal. The whole process is so fast that you can't even feel it, but the accuracy is very high.
This is a very classic selection question. Simply put, plastic gear servos are cheap and light in weight, and will damage the gears first when overloaded, thus protecting the more expensive motors and circuit boards inside. They are suitable for use on small models or robots that do not require high torque.
Metal gear servos are much stronger. Their gears have high strength, can withstand large torsional impacts, and have a longer service life. Of course, the price is expensive and heavy. If it gets stuck, its powerful gears may transmit impact force to the motor, causing the motor to burn out. So which one to choose depends on your application scenarios and budget.
When you get the servo parameter sheet, don’t be intimidated by a bunch of numbers. You just need to focus on three core indicators: torque, speed and accuracy. Torque is usually expressed in kg·cm (kg·cm), which tells you how strong the steering gear can be. For example, 30kg·cm means that the end of a 1cm long swing arm can pull 30kg.
Speed is generally expressed in "seconds/60 degrees", such as 0.1 seconds/60 degrees, which means it takes 0.1 seconds to turn 60 degrees. The smaller the value, the faster the movement. The accuracy is reflected in the angle error under no-load and load conditions, as well as whether there is hysteresis, which are related to whether your product's movements are delicate and in place.
You may find that some servos have the word "number" marked on the front. The core difference between analog servos and digital servos is the control circuit. The signal processing frequency of the analog servo is relatively low, and the response to small movement commands will be half a beat slow, and there may be a slight jitter near the neutral point.
Digital servos have built-in more powerful microprocessors that can process and send control signals at much higher frequencies. This means it responds faster, positions more accurately, and starts and brakes more sensitively. Although it is more expensive, it is definitely a better choice for applications that require higher dynamic performance, such as robotic arms or competitive robots.
In addition to parameters, there are also some small details worth paying more attention to. For example, the common standard for the servo output shaft tooth number is 25T. If the servo you choose does not match the tooth number of your existing swing arm, it will not be installed. Another example is the cable length. The purchased cable is not long enough, and it is troublesome to connect it yourself, which will delay things.
In addition, the operating voltage range is also important. Some servos can only work from 4.8V to 6V, while others can support 7.4V or even higher. If the battery voltage you use is relatively high, it will easily burn out if you choose the wrong servo. Finally, there is also the waterproof and dustproof rating. If your product needs to be used outdoors or in harsh environments, remember to choose a model with corresponding protection capabilities.
After understanding this, will it be much clearer when looking at the steering gear? When choosing a model next time, you might as well try to choose based on the internal structure and working principle, combined with your actual needs. If you are still a little unsure, go directly to the official website of the steering gear manufacturer and look for their technical support and selection guide. You can usually get very professional help.
What is the most difficult steering gear problem you have ever encountered while working on a project? Welcome to leave a message and share it in the comment area. Let’s discuss it together. If you find it useful, don’t forget to like and forward it!
Update Time：2026-02-21
Contact Kpower's product specialist to recommend suitable motor or gearbox for your product.
