The word "servo" originates from the Greek word for "slave." People envisioned a "servo mechanism" as a docile tool, obeying the commands of control signals. Before a signal arrives, the rotor remains stationary; after the signal arrives, the rotor immediately begins to rotate; when the signal disappears, the rotor stops instantly. Because of its "servo" performance, it is named a servo system.
The most common type of servo motor is the AC permanent magnet synchronous servo motor. Inside the servo motor, the rotor is a permanent magnet, and the stator is a three-phase winding . The driver controls the U/V/W three-phase electricity to create a changing electromagnetic field in the stator. The rotor rotates under the influence of this magnetic field. Simultaneously, the motor's built-in encoder feeds back signals to the driver. The driver compares the feedback value with the target value and adjusts the rotor's rotation angle accordingly. The accuracy of the servo motor depends on the accuracy (line count) of the encoder. The most common type is the servo motor configured with a 2500-line standard encoder.
Tamagawa Servo Motor Classification
Servo motors, also known as actuator motors, are used as actuators in automatic control systems to convert received electrical signals into angular position or angular velocity outputs on the motor shaft. They are divided into two main categories : DC and AC servo motors .
In AC servo systems, motors are categorized into permanent magnet synchronous AC servo motors (PMSM) and induction asynchronous AC servo motors (IM). PMSMs, with their excellent low-speed performance, ability to achieve high-speed control with field weakening, wide speed range, and high dynamic characteristics and efficiency, have become the mainstream choice for servo systems. While induction AC servo motors are robust, simple to manufacture, and inexpensive, they lag behind in terms of characteristics and efficiency, and are only valued in high-power applications.
The performance indicators of AC servo systems can be measured from aspects such as speed range, positioning accuracy, speed stability, dynamic response, and operational stability. Mid-to-low-end servo systems have a speed range of 1:1000 or higher, typical systems range from 1:3000 to 1:10000, and high-performance systems can reach 1:100000 or higher. Positioning accuracy generally needs to reach ±1 pulse. Speed stability, especially at low speeds (e.g., at a given 1 rpm), is generally within ±0.1 rpm, and high-performance systems can reach within ±0.01 rpm.
Dynamic response: A typical servo motor can reach its rated speed from 0 to 10 ...
