A failure of a machine or the like is rapidly detected to efficiently operate the machine. A cell control device of a production system includes a product information monitoring unit for monitoring the product information, a component supply state monitoring unit for monitoring plural kinds of components to be supplied to at least one cell and the number of each kind of components, and a notification unit which transmits a notice to a higher-level management controller when the number of each kind of components, which is monitored by the component supply state monitoring unit, deviates from a predetermined range determined for each kind of components.

A data aggregation unit acquires quality data and apparatus-information data. With respect to the quality data and the apparatus-information data acquired by the data aggregation unit, a condition setting unit sets data items of data to be counted up, a base condition indicating a condition that constitutes a basis of quality analysis, and a comparison condition indicating a condition subjected to the quality analysis. A distribution difference calculation unit extracts from the quality data and the apparatus-information data acquired by the data aggregation unit, data that meets the base condition and data that meets the comparison condition, for each of the data items set by the condition setting unit, and calculates frequency distributions of these data for each of the data items, and outputs data indicating a degree of divergence between the frequency distribution of the base condition and the frequency distribution of the comparison condition.

A machine tool includes a tool and a workpiece machined by the tool, and sensors configured to detect a position of the tool and/or the tool holder holding the tool in a spatially and time resolved manner A method for offline and/or online identification of a state of the machine tool includes: a) detecting or providing positions p.sub.i of the tool and/or of the tool holder at a series of points in time i, i=1 . . . n; b) determining for the series of points in time i a series of position changes ?m.sub.i according to the formula ?m.sub.i=p.sub.i/p.sub.i-1 and a series of speed changes ?v.sub.i according to the formula ?v.sub.i=v.sub.i/v.sub.i-1 with $v_i=\frac{P_i-P_{i-1}}{t_i-t_{i-1}}$
and formula $v_{i-1}=\frac{P_{i-1}-P_{i-2}}{t_{i-1}-t_{i-2}};$
c) identifying the state of the tool, the tool holder, the machine tool and/or the workpiece machined in the machine tool based on the position changes ?m.sub.i and the speed changes ?v.sub.i.