Patent ID: 6920370

Claim:
A method for disturbance sensing in a drive system of a numerically controlled machine tool, in which at least one drive motor for positioning a machine part is coupled via one or more transmission elements to the machine part, the method comprising the steps of: a) measuring a position of a moving machine part directly on the machine part and also indirectly at at least one location in a transmission chain; b) comparing the direct and indirect position measured values to reach a difference value; and c) comparing the difference value to a prescribed threshold value during operation of the machine tool to determine the occurrence of a disturbance, the disturbance indicated if the difference value exceeds the prescribed threshold value, the disturbance indicative of at least one of a dynamic error of the drive motor, a dynamic error of one or more of the transmission elements, or a collision between the moving machine part and an object, the comparison performed with consideration of actual operating conditions.