Design of a Multi-Point Kinematic Coupling for a High Precision Telescopic Simultaneous Measurement System

Abstract

This paper covers the design of a new multi-point kinematic coupling specially developed for a high precision multi-telescopic arm measurement system for the volumetric verification of machine tools with linear and/or rotary axes. The multipoint kinematic coupling allows the simultaneous operation of the three telescopic arms that are registered at the same time to a sphere fixed on the machine tool spindle nose. Every coupling provides an accurate multi-point contact to the sphere, avoiding collisions and interferences with the other two multi-point kinematic couplings, and generating repulsion forces among them to ensure the coupling’s fingers interlacing along the machine tool x/y/z travels in the verification process. Simulation presents minimal deformation of the kinematic coupling under load, assuring the precision of the sphere-to-sphere distance measurement. Experimental results are provided to show that the multi-point kinematic coupling developed has repeatability values below ±1.2 µm in the application.

Thermal Error Compensation Strategy in Simultaneous Laser Multilateration for Volumetric Verification

“…The HPTI simultaneously measures three distances from three fixed points in the working table of the productive system to an only sphere fixed to the machine header. Each telescopic arm of the HPTI is equipped with a special design multi-point kinematic coupling (trident) [10] to allow the junction of the three telescopic arms to the same sphere at the same time. The three tridents enable a simultaneous multilateration to calculate the position of the machine header from the three distances measured by the HPTI (Fig.…”

“…1.c). The HPTI under study in this paper, its main parts and its working principle is explained in [8][9][10]. In order to obtain the absolute values of the distance between the spheres from the lectures of the interferometers integrated in the HPTI an initial adjustment of the telescopic arms is needed.…”