Unknown free-form surface self-adaptive measuring method based on exploration method and measuring head device

Abstract

The invention discloses an adaptive measurement method and a measuring head device for an unknown free-form surface based on a pathfinding method. Install the touch probe between the two laser probes, and install the whole device on the Z-axis of the coordinate measuring machine. Use the signals of the two laser probes for path detection, and the touch probe is used for measurement; when the touch probe During the movement of the probe from the current measurement point to the next point to be measured, the laser probe probes the previous measurement path with a sampling step size of 0.5-2mm, and after processing the obtained measurement data, the fitting into a cubic uniform B-spline curve; then the fitted curve is discretized into adaptive sampling points according to the curvature, and corresponding obstacle avoidance points are generated at the same time; then these sampling points and obstacle avoidance points are used to guide contact measurement , to achieve adaptive measurement of unknown free-form surfaces. The method has a simple algorithm, a simple device structure and is easy to implement.

Description

technical field [0001] The invention relates to the measurement of irregular surfaces or contours, in particular to an adaptive measurement method for unknown free-form surfaces based on a pathfinding method and a measuring head device. Background technique [0002] In the field of mechanical manufacturing, a large number of parts with free-form surfaces are involved, such as automobile body panels, engine air ducts, steam turbine blades, aircraft wings, etc. The design, manufacture and inspection of these components are directly related to the digital measurement of free-form surfaces, that is, a series of discrete sampling points are used to extract the original shape information of the surface. The three-coordinate measuring machine is the most widely used in the digital measurement of free-form surfaces due to its high precision and intelligence. [0003] One of the keys is to determine a reasonable sampling method when using a three-coordinate measuring machine to digi...

AI Technical Summary

Problems solved by technology

In the subdivision iterative method, the determination of the initial grid size has a great influence on the measurement process, but since the surface model is unknown, there is no reasonable basis for determining the initial network size, and the initial grid size is generally set empirically

This method is rarely used in practice

At the same time, none of the above four methods has the ability to identify boundaries, and all require manual setting of the measurement boundaries of free-form surfaces before measurement.

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