TECHNICAL SUPPORT
Published 2026-05-01
Digital mg super sub microservo(Digital signal metal gear ultra-miniature steering gear) is a miniature actuator that integrates a digital control circuit and has a metal transmission gear. Its body size is less than 20mm×10mm×20mm. Its typical weight is 5 - 9 grams, the operating voltage is 4.8 - 6.0V, and the stall torque is usually between 1.5 - 3.0 kg·cm.The digital signal indicates that the servo uses a high-speed MCU to analyze PWM pulses. Compared with the analog servo, it has faster response speed, higher holding torque and more accurate midpoint positioning.. Metal gears, also known as mg, replace plastic gears, and their impact resistance and service life are significantly improved. Plastic gears are prone to teeth breakage when subjected to repeated loads or accidental collisions. However, metal gears can withstand more than 3 times the instantaneous impact. The ultra-miniature design, also known as super sub micro, allows it to be embedded in a space the size of a fingertip. It is commonly used in application scenarios that are extremely sensitive to size and weight, such as miniature aircraft models, desktop robot finger joints, and micro robotic arms.
Five corresponding indicators as shown below must be clarified before selection. If any single one of them is missing, it is very likely to cause the project to fail:
It is important to note that the PWM signal frequency of digital servos is generally 50 to 330Hz, and the pulse width range is 500 to 2500μs, corresponding to the rotation angle of 0 to 180°. Before use, you must use an oscilloscope or a servo tester to confirm the neutral point pulse width generated by the controller output. This pulse width is usually It is 1500μs, otherwise it may cause the servo to overheat or the stroke to exceed the limit. An enthusiast once directly connected the flight control but it was not calibrated, which caused the servo to continue to stall at the extreme position and burn the coil. Faults like this account for more than 40% of after-sales repairs.
Case 1: Miniature bipedal robot hip joint
The design set such a goal. The total weight of the robot is 200g. When it is supported by one leg, the load borne by the hip joint is about 100g. The length of the moment arm is 2.5cm. According to the calculation, the required torque is equal to 0.1kg times 2.5cm, which is 0.25kg·cm. Determined to choose after selectiondigital mg super sub microservo(The torque is 2.0kg·cm), the safety factor reaches 8 times, which can meet the corresponding requirements. After actually walking for 1,000 steps, the plastic gear version showed tooth surface wear, but the metal gear version had no visible wear. It is concluded that in scenarios where forward and reverse rotations occur frequently, metal gears are a necessary choice.
Case 2: Micro FPV fixed-wing aileron servo
There is an aircraft with a wingspan of 400mm. When the aileron control surface is impacted by airflow, the maximum load it bears is about 0.8kg·cm.The aircraft uses a digital micro-servo with a torque of 1.5kg·cm. The rudder shakes when performing high-G maneuvers.。After analysis, it was found that the reason is that although the digital servo responds very quickly, there is an issue with insufficient power supply - the receiver BEC can only provide 0.5A of current, and the instantaneous peak current of the servo reaches 1.2A, which leads to a voltage drop and restart.. In response to this problem, the solution given is to install a 1000μF capacitor or replace a BEC that can provide 2A current.
Key steps: Before installing any micro-servos, be sure to conduct the following three-step verification:
1. When performing no-load testing, use a steering gear tester to send a pulse width that gradually increases. Listen to the gear rotation to see if there are no abnormal sounds. Also observe the angle linearity to see that there is no jump.
2. Block the rotation for testing: lock the rocker arm for a short period of time (less than 1 second), measure the current, and see if the current is close to the nominal value in the specification (generally 0.5 - 1.0A). If it does not match, there may be an inter-turn short circuit.
3. For the temperature rise test, the requirements are that the reciprocating motion needs to be continuous for 2 minutes. After that, the temperature rise of the shell should be <25°C, which means it feels lukewarm when touched by hand. If overheating occurs, it indicates that the efficiency of the motor is low, or the friction between the gears is too large.
Q1: Can digital servos and analog servos be mixed?
A: It is not possible to mix and use them directly. Digital servos have requirements for high-frequency signals, requiring their frequency to reach ≥200Hz, while analog servos only support frequencies of 50Hz. If they are mixed, it will cause the digital servos to heat up, or cause the analog servos to vibrate.
Q2: Do metal gears need lubrication?
A: The product already contains solid grease when it comes from the factory, and does not need to be added. If you inject lubricating oil into it yourself, it will absorb dust and accelerate wear, and it may also penetrate into the potentiometer and cause signal drift.
Q3: What should I do if the neutral point of the ultra-miniature steering gear always deviates?
A: You need to calibrate the remote control first, and then perform self-learning of the servo. Some digital servos support entering the programming mode by long pressing the signal line. You need to reset 1500μs as the midpoint.
Q4: Which power supply voltage is 5V or 6V?
Priority is given to 6V, within the rated range. The higher the voltage, the greater the torque, and the faster the speed. However, pay attention to check the maximum withstand voltage of the servo, usually 6.5V is the limit.
Q5: Can I buy the metal rocker arm alone after the rocker arm has been scanned?
Regarding item A, this cannot be done because the specifications of the output gear of the ultra-miniature servo are not standardized, so a rocker arm of the same brand must be used to support it. If the installation is forced, the output gear will be damaged.
The core values are repeatedly reflected: high-precision control of digital signals, high durability of metal gears, and high integration in ultra-miniature sizes.digital mg super sub micro servocore value. When your project meets the three conditions of "limited space, frequent load fluctuations, and the need for quick response", this type of steering gear is the only reasonable choice.
Regarding procurement, experts suggest that two documents should be obtained from the supplier before purchasing. The first is the gear material certification document, whose purpose is to confirm that the material involved is brass or powder metallurgical steel, and not the material of copper-plated iron teeth; the second is the digital signal timing diagram document, whose purpose is to verify the linearity between pulse width and angle within the range of 200 to 500Hz. According to Article 5.3 of the "General Technical Conditions for Micro Motors" (GB/T 7345-2018), manufacturers must provide the above data. If they are unable to provide it, it will be regarded as a substandard product.
Final action list:
Measure the actual installation dimensions and mark the screw hole locations and cable outlet directions.
Calculate the maximum load torque and multiply it by 1.5 times the safety factor before selecting the model.
Check the PWM frequency of the controller to make it compatible with the servo. The frequency range supported by most digital servos is 50 - 330Hz.
Independent power supply to avoid sharing BEC with high-current equipment such as motors and LEDs
Perform neutral point calibration and travel limit testing for first time use
Follow these steps and your micro drive system will achieve lab-grade reliability and a lifespan of over 5,000 full load cycles.。
Update Time：2026-05-01
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