Thermal Error Compensation Strategy in Simultaneous Laser Multilateration for Volumetric Verification

Abstract

Verification systems are needed for periodic verification and calibration of robots and machine tools to maintain and increase their accuracy. One of the ways to verify the volumetric accuracy of a manufacturing system is to measure the position of its head (X, Y, Z coordinates) using measurement systems that provide these results with the appropriate precision. The laser interferometer provides results with accuracy levels suitable for robot and machine tool verification applications. However, to measure the head position of manufacturing systems (X, Y, Z coordinates), the use of laser interferometers requires a prior adjustment to a reference length, since they measure incrementally. This adjustment procedure of the measurement system introduces an error in the resulting head coordinates that depends on the environmental conditions and the material of the standard element used to materialize the reference length. This paper analyzes the temperature effect in the adjustment process and how temperature errors introduced in said process affect the head 3D coordinates calculation of the Manufacturing System under inspection.