Definition of open-loop control in CNC machines

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An open-loop control system is a control system in which the regulating mechanism does not take feedback into account; it only controls the output without considering the consequences. Also known as a feedback-free control system. In CNC machines, it consists of a stepper motor and the circuitry that drives the stepper motor. The CNC unit, based on the input commands, performs calculations and sends pulse commands to the stepper motor drive circuit, thereby driving the worktable to move a certain distance. This type of servo system is relatively simple, operates stably, and is easy to use, but improvements in precision and speed are limited. Therefore, it is generally used only in some cost-effective CNC machines where external influences can be ignored, or where inertia is low, or where the precision requirements are not high.