An open-loop servo system is a type of motion control system where the control action (command signal) is executed without relying on feedback from the system's output or position. The system operates based solely on predetermined inputs and does not adjust its performance based on actual output conditions.

Open loop servo system is a control system that does not rely on feedback signals, and its core characteristics are:

• No feedback mechanism: System outputs (such as position and velocity) are not fed back to the controller through sensors.
• Execution logic: The controller directly drives the actuator (such as a stepper motor) based on preset instructions, assuming that the instructions and execution results are completely consistent.

A typical open-loop servo system includes:

• Controller: Generate control signals (such as pulse sequences).
• Actuators, such as stepper motors and open-loop DC motors, directly respond to control signals.
• Load: The mechanical structure that is driven.

1. Low precision demand scenarios: such as economical 3D printers, simple CNC machine tools, and low-cost automation equipment.
2. Static or low dynamic load: When the load remains constant or changes slowly, error accumulation is acceptable.

Typical applications of open-loop stepper motors:

3. 3D printer: The nozzle movement is controlled by a fixed number of steps, and interlayer errors do not affect the overall printing.
4. Simple CNC machine tools, such as economical engraving machines, do not require feedback correction when the material hardness is uniform.