Ultra-precise straightness measuring method based on single-measuring-head error separation

Abstract

The invention discloses an ultra-precise straightness measuring method based on single-measuring-head error separation. The method comprises the implementing steps that a measured workpiece is placed on a machine tool, and a scanning measuring head is mounted on a movement mechanism of the machine tool through a shearing platform provided with a micro-displacement structure; starting from the starting position of a selected moving distance, the movement mechanism is controlled to drive the scanning measuring head to conduct amplitude -limited movement, and every time the scanning measuring head is moved to a detection position, the scanning measuring head is driven by the shearing platform to conduct micro-displacement to collect distance detection data of at least two positions in the micro-displacement process until data acquisition of all detection positions of the measured workpiece at the selected moving distance is completed; the distance detection data collected at all the detection positions are subjected to error separation through a preset error separation algorithm to obtain a straightness measuring result. The method has the advantages that measurement accuracy is high, the scanning area is large, the measuring range is large, measurement is convenient and fast, influences of environmental low-frequency vibration can be suppressed, and influences of zero setting errors, spacing errors, property difference and thermal drift of the measuring head are eliminated.

Description

technical field [0001] The invention relates to the technical field of measurement applications, in particular to an ultra-precision straightness measurement method based on single-probe error separation, which is mainly applied to the straightness, flatness, ultra-precision optical surfaces and even optical free-form surfaces of precision and ultra-precision workpiece surfaces The measurement of surface shape can also detect the straightness error of the motion platform. Background technique [0002] In precision and ultra-precision machining, in order to measure the straightness motion error of the guide rail, the straightness profile, flatness and surface shape accuracy of the workpiece surface, etc., the scanning measurement method is often used. This method uses the displacement probe (commonly used non- Contact sensors (such as capacitance or eddy current, etc.) or angle detectors (such as autocollimators, etc.) are installed on a mobile platform and move linearly alon...

AI Technical Summary

Problems solved by technology

However, when using multi-probe scanning measurement, there will be the following problems: 1. The zero-adjustment error of each probe will introduce a parabolic cumulative error, the larger the scan size, the more significant the impact, and the zero-adjustment error is difficult to achieve high precision Calibration; 2. The distance between multiple probes will deviate from the ideal position due to the influence of installation hole distance, aperture, probe outer diameter accuracy and clamping force, and the actual distance is difficult to measure with high precision. The spacing error will also affect the reconstruction accuracy of the measured surface profile. When scanning large-sized parts or measuring with high lateral resolution, this error will have a great impact; 3. The characteristic difference between different probes will also lead to reconstruction error

In actual measurement, sometimes it is difficult for the workpiece under test to be flipped or dislocated, so these two methods are difficult to implement; and since at least two scans are required, the repeatability of the slide will also affect the measurement results

In addition, the relative vibration between the measured surface and the probe, and when the measurement time is long, the thermal drift of the probe will have a greater impact on the measurement

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