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Published 2026-03-09
When playing with theservo, do you always feel that it moves like a "robot" - either it doesn't move, or it suddenly turns into position with a clang, making the whole project look particularly stiff? Especially when innovating products that require a "silky" effect, such as smart cars, robotic arms, or bionic robots, this problem is really a headache. In fact, controlling the rotation speed of theservois not as complicated as imagined. If you master the correct method, your works can also have smooth movements.
Many friends will look through theservoparameter table when they first get started, trying to find a knob called "speed adjustment". But the conventional servo is essentially a position servo. It only recognizes the target angle, not the speed. You give it a signal, and its goal is to turn to that position "immediately". As for how fast it turns, it depends on its internal motor and gear set, that is, its "no-load speed" parameter. Therefore, if you want to directly adjust the speed, you have to change your thinking: you cannot let it reach the target in one step, but give it a series of continuous "small goals".
This is usually caused by the control signal jumping too much. For example, if you ask the servo to turn directly from 0 degrees to 90 degrees, it will rush over with maximum strength and speed, and it will visually "click". Especially when doing bionic applications, such as the swing of the tail of a robotic fish, this stiff movement is unnatural and will also cause impact on the steering gear. The fundamental reason is that we did not consider the continuity of motion and simplified the continuous motion into a few isolated points.
The most basic method is the "segmented delay method". You can divide the 90-degree target trip into 9 parts, each part is 10 degrees. First send a signal of 10 degrees and wait for 50 milliseconds; then send a signal of 20 degrees and wait for another 50 milliseconds... In this way, "feed" the servo bit by bit, and it will go up step by step like climbing stairs. The longer the delay, the slower the climb. This trick is very easy to implement on such platforms, and the code logic is simple. It is especially suitable for friends who are just getting started with servo applications to quickly verify their ideas.
The benefits of this method are immediate, but the level of detail depends on how many "ladders" you divide. If you divide 90 degrees into 90 parts, each part is 1 degree, and the delay is 10 milliseconds, the action will look quite coherent. However, please note that if the delay is too small and is less than the response time of the servo itself, it may not be able to respond and cause jitter. So here’s a little tip: Match the number of steps and delay time to find the most comfortable “silky point” in your project.
Of course you can, and this is the most mainstream approach currently. We abandoned the method of manually writing a bunch of delays and instead used a for loop to generate continuous "target positions". Specifically, the form of "current angle += 1" is used to continuously calculate the next tiny angle inside the loop, and then send instructions. In this way, the operating effect of the servo is like walking on a gentle slope without steps. Moreover, by using trigonometric functions (such as sin waveforms) to calculate the target value, you can even make the robotic arm behave like a real arm, with acceleration and deceleration processes, and its start and stop are particularly soft.
In actual operation, this method greatly improves the smoothness and naturalness of the robotic arm movement. By accurately using for loops and trigonometric functions, we can control the movement trajectory of the robotic arm more precisely. Every small change in angle has been carefully calculated to ensure that the robotic arm can achieve a smooth transition during operation. Whether it is slow acceleration when starting or gradual deceleration when stopping, it shows a high degree of coordination, as if imitating the natural movements of a real human arm, providing broader possibilities for expanding the application scenarios of the robotic arm.
If you want to avoid complicated programming, there are many "intelligent serial bus servos" on the market that are a good choice. This type of servo has a control chip inside. You only need to send a simple command, such as "turn to 90 degrees in 3 seconds", and it will plan the process of acceleration, constant speed and deceleration. For example, some LX series servos used in robot competitions support this kind of command. For innovators making complex products, this can greatly simplify the control logic and focus on higher-level functional design.
In the actual process of writing code, it is not recommended to use "delay" in the main loop to block time. This is because the microcontroller is in a stagnant state during the "delay" period and cannot perform any other operations. A more efficient way is to use "non-blocking programming", specifically, to use the "timer" or "()" function to perform timing work. During each loop, the time is checked, and if the time since the last move exceeds the preset interval (for example, 20ms), the next position is calculated and sent. In this way, the microcontroller can handle other tasks such as sensor reading and screen display at the same time, so that the entire system can operate efficiently.
When this efficient approach is adopted, the microcontroller can flexibly handle various transactions in each cycle. By checking the time, once it is found that the conditions are met, the next position can be calculated and sent in time, making full use of every opportunity in the cycle. In this way, the microcontroller will not be bound by "delay" and can handle time-related tasks while also taking into account other important tasks such as sensor reading and screen display in an orderly manner, thereby ensuring that the entire system can run smoothly and efficiently, realizing the collaborative work of various functions, and providing a strong guarantee for the stability and efficiency of the entire system.
After talking about so many control methods, I wonder which one you use most when doing product innovation? Or have you ever encountered any particularly difficult servo control scenarios? Welcome to share your experience and confusion in the comment area, and let’s communicate and make progress together. If you think this article is helpful to you, don’t forget to like and share it so that more friends who play servos can see it!
Update Time：2026-03-09
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