Servo motor is the core executing component of modern automation systems, whose core function is to achieve high-precision, high response, and high dynamic performance motion control. It is not just about "rotation", but can accurately control key motion parameters such as position, speed, and torque. The following is the logical analysis of its core functions:
Accurate position control:
Core competency: This is the most prominent function of servo motors. It can drive the motor shaft or load to a specified angle or linear position based on command signals (such as pulse numbers or digital commands) and maintain it at that position.
Implementation principle: By using a built-in high-resolution encoder (or rotary transformer) to provide real-time feedback on the actual position of the motor rotor, the controller compares the actual position with the commanded position (forming a closed loop), calculates the error, and drives the motor to quickly and accurately eliminate this error.
Application manifestations: The tool positioning of CNC machine tools, angle control of robot joints, nozzle movement of 3D printers, and placement of parts on precision assembly lines all require sub millimeter or even micrometer level repetitive positioning accuracy.
Accurate speed control:
Core ability: The servo motor can strictly follow the instructions and maintain a very stable speed within a wide speed range (from extremely low speed to high speed). Even in the case of load fluctuations, it can quickly adjust and maintain the set speed.
Implementation principle: The encoder simultaneously feeds back the actual speed, and the controller compares it with the commanded speed. By adjusting the motor current (torque), it overcomes load changes and maintains a constant speed.
Application manifestations: synchronous speed regulation of production line conveyor belts, constant line speed winding of textile machinery, constant cutting speed of spindle machining (such as lathes and milling machines), precise synchronous cutting of flying shear equipment, etc.
Accurate torque control:
Core Capability: The servo motor is capable of outputting and precisely controlling the rotational force (torque) applied to the shaft. It can maintain a constant torque output or output a specific torque curve when needed.
Implementation principle: The controller precisely controls the current delivered to the motor based on the commanded torque value (because torque is proportional to current). Some systems also provide closed-loop feedback through additional torque sensors.
Application manifestations: screw tightening machine (constant torque tightening), winding machine (constant tension winding), press machine (precise pressure control), collaborative robots that require "compliant" operation (control contact force), etc.
Fast dynamic response:
Core competency: The servo system has extremely high response speed. It can quickly receive instructions, detect errors, calculate compensation, and output the required current for adjustment, thereby achieving high-speed start stop, rapid acceleration and deceleration, and instantaneous reversal.
Implementation principle: Low rotor inertia design, high-performance permanent magnets, high gain control algorithms (such as PID and its variants), and high-speed communication interfaces work together to make the system response time extremely short.
Application manifestations: high-speed surface mount machine (fast picking/placing of components), laser cutting/engraving (high-speed contour tracking), Delta parallel robot (high-speed sorting), occasions requiring frequent start stop and direction change.
Excellent anti-interference and adaptive capabilities:
Core capability: In the event of sudden changes in load (such as increased cutting resistance, changes in material weight) or external disturbances (such as vibration), the servo system can quickly sense and compensate through a closed-loop feedback mechanism to maintain the set motion state (position, speed, torque).
Implementation principle: Real time feedback is the core. The controller constantly compares instructions with actual values, and any deviation will be detected and quickly corrected.
Application manifestation: Maintaining machining accuracy and stability in automated equipment with complex working conditions and unstable loads, such as opening and closing molds in injection molding machines and maintaining the speed of AGV vehicles to overcome uneven road surfaces.
The core function of a servo motor is essentially to achieve high-precision, high response speed, and high stability dynamic control of the motor's motion state (position, speed, torque) through real-time closed-loop feedback mechanisms (position, speed, current/torque feedback) and precise control algorithms. It is like an extremely sensitive and obedient 'motion executor', capable of accurately completing tasks such as' where to go ',' how fast to go ', and' how much force to use 'under various complex conditions based on instructions from the brain (controller). It is an indispensable key component of modern high-precision, high-efficiency, and highly flexible automation. Its value lies not only in its ability to move, but also in its ability to move accurately, quickly, and intelligently.