Multi-degree-of-freedom displacement measurement system for milli-structures

Abstract

A new multi-degree-of-freedom measurement system for milli-structures is presented. This methodology is based on optical beam deflection method and triangulation. It employs a diffraction grating as a reflective object, which reflects an incident laser beam into several directions. To obtain the pose information of a measured object, the detecting positions of zeroth- and first-order diffracted rays are measured using three two-dimensional detectors. From these values, we can calculate six-degree-of-freedom displacement through a kinematic analysis. The performance was evaluated with resolution, measurement errors and crosstalk. The results show that measurement errors and maximum crosstalk are within ±0.5 µm in translation and ±2'' in rotation. As an application, we measured the multi-DOF motion of a bimorph type PZT actuator and obtained its frequency response function.

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“…Many optical structures for multi‐DOF measurements have been proposed, based on different types of GIs. It includes in‐plane displacement measurement, 62,63 out‐of‐plane displacement measurement, 64,65 and rotational measurement 66,67 …”

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A high-precision five-degree-of-freedom measurement system based on laser collimator and interferometry techniques

“…Since the 1960s, many optical measurement methods [1][2][3][4][5][6][7][8] were invented, such as the diffraction optical method. The accuracy measurement of computer numerical controls ͑CNCs͒ and machining centers is a crucial part for machine tool manufacturer and industry which could be used to monitor and improve the machine tool accuracy.…”