A servo motor is a closed-loop system that enables precise control of mechanical movement in automatic control systems. These motors allow for angular or linear position, speed, and acceleration control, maintaining the target position with high accuracy thanks to a feedback mechanism. They are widely used in industrial robots, RC (radio-controlled) vehicles, CNC machines, and automation systems.

Servo Motor Internal Structure (Created with Artificial Intelligence)
The foundation of servo motors dates back to hydraulic systems in the 19th century. The first electric servo motor was developed in the 1920s by John C. Stevens. During World War II, their use expanded in artillery systems and radar antennas. With the advancement of microprocessor technology in the 1970s, modern servo motors became standard in industrial production lines.
Servo motors are controlled via PWM (Pulse Width Modulation) signals. The control signal consists of electrical pulses repeated at specific intervals. The pulse width determines the motor's target position:
The motor processes the incoming signal every 20 ms. The feedback sensor continuously measures the shaft's position. The control circuit moves the motor until the difference (error signal) between the target and current position is minimized. This closed-loop system ensures precision and stability.
Mezher LS. Characteristics of Servo DC Motor with PID Controller. Journal of Mechanical Engineering Research and Development. 2021;44(2):392-400 [accessed May 12, 2025]. Available at: https://www.researchgate.net/publication/349313247_Characteristics_of_Servo_DC_Motor_with_PID_Controller
Akash RK. Comparative Analysis of Control Strategies for Position Regulation in DC Servo Motors. arXiv preprint arXiv:2501.11820; 2025 [accessed May 12, 2025]. Available at: https://arxiv.org/abs/2501.11820
Tokel Ç. Design and Implementation of a Four-Axis RC Servo Motor-Driven Robot Manipulator. İzmir: Dokuz Eylül University Institute of Natural Sciences; 2009 [accessed May 12, 2025]. Available at: https://dergipark.org.tr/tr/pub/utbd/issue/36156/406614
Servo Motors and an Example Application Design. Marmara University AVESİS; 2023 [accessed May 12, 2025]. Available at: https://avesis.marmara.edu.tr/yonetilen-tez/200ac561-3723-4381-a42c-ae6291e04adf/servo-motorlar-ve-ornek-bir-uygulama-tasarimi
History
Components
Motor
Feedback Sensor
Control Circuit
Gearbox
Working Principle
Example PWM Values
Types of Servo Motors
Positional Rotation Servo
Continuous Rotation Servo
Linear Servo
AC and DC Servo Motors
Applications
Advantages and Disadvantages