Selection optimization method of temperature measurement point combination for positioning errors of numerically-controlled machine tool under thermal effect

Abstract

The invention provides a selection optimization method of a temperature measurement point combination for positioning errors of a numerically-controlled machine tool under thermal effect. The selection optimization method is capable of identifying the influence of the temperature measurement point in each position on the positioning errors of the machine tool based on a grey correlation policy and a rough set theory. The selection optimization method comprises the following steps: k temperature sensors are mounted in special positions of the machine tool to measure the real-time temperature values, changing over time, of the machine tool during operation, and meanwhile, a laser interferometer is used for measuring positioning error values affected by temperatures; n sensitive temperature measurement point positions are screened out by use of the grey correlation policy; the positioning errors and the temperature data of the machine tool are preprocessed according to the principle of the rough set theory and a policy table is established; m feasible temperature point combinations are obtained by use of rough set reduction software; the optimal temperature measurement point combination of the machine tool is identified by virtue of comprehensive analysis. The selection optimization method of the temperature measurement point combination for the positioning errors of the numerically-controlled machine tool under the thermal effect is capable of solving the problem of excessive temperature measurement points or poor compensation model robustness in the positioning error compensation modeling process of the numerically-controlled machine tool.

Description

technical field [0001] The invention relates to a method for optimizing the combination of temperature variables used in the measurement of machine tool positioning errors and error compensation modeling in the cutting process of numerical control machine tools, belonging to the technical field of numerical control machine tool error analysis. Background technique [0002] The positioning accuracy of CNC machine tools is the position accuracy that the moving parts of the machine tool can achieve under the control of the CNC system. Generally speaking, it refers to the accuracy with which the machine tool positions the tool tip to the target point in the program. The machining accuracy of the machine tool is ultimately determined by the relative displacement between the tool and the workpiece on the machine tool. Therefore, reducing the positioning error is very important to improve the machining accuracy of the machine tool. [0003] Due to its good economy and high feasibi...

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Problems solved by technology

[0004] However, too many temperature measuring points will not only increase the workload of arranging the measuring points, but also make the output signals of adjacent measuring points more correlated, which will affect the calculation accuracy.

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