Abstract: The mathematical model of power monitoring system in machining is created in this paper from the energy transmission mathematical model of a machine tool. The model has manifold functions and uses in studying the dynamic response characteristic of power information along with the change of cutting state, analyzing the varying regularity of power information being acted by the disturbances, identifying the wearing or breaking state of the tools, diagnosing some mechanical faults, measuring some cutting state parameters and so on, which lays foundation for the further studies and applications of the power monitoring technology.

Key words: 功率监控, 机床, 数学模型