Laser measurement system dedicated to the determination of rails deformation of a hybrid electromagnetic launcher

The growing applications area of an electromagnetic launcher lead to numerous researches on new constructions and analyzes of existing and novel solutions of this type of device. The typical solutions with a coil or rail drive (named coil-gun and rail-gun) as well as a new hybrid construction which is a combination of these two types of drives are known. The paper presents the construction and mathematical model of the hybrid electromagnetic launcher (containing coil-gun and rail-gun module) with pneumatic assists, but the main purpose of this paper is to present measurement and simulation results of rails deformation for an electromagnetic launcher with rails (rail-gun module). The computer simulations were made using Inventor Professional software. In the measurement system the laser displacement sensor was used.

Error Analysis and Compensation of a Laser Measurement System for Simultaneously Measuring Five-Degree-of-Freedom Error Motions of Linear Stages

A robust laser measurement system (LMS), consisting of a sensor head and a detecting part, for simultaneously measuring five-degree-of-freedom (five-DOF) error motions of linear stages, is proposed and characterized. For the purpose of long-travel measurement, all possible error sources that would affect the measurement accuracy are considered. This LMS not only integrates the merits of error compensations for the laser beam drift, beam spot variation, detector sensitivity variation, and non-parallelism of dual-beam that have been resolved by the author’s group before, but also eliminates the crosstalk errors among five-DOF error motions in this study. The feasibility and effectiveness of the designed LMS and modified measurement model are experimentally verified using a laboratory-built prototype. The experimental results show that the designed LSM has the capability of simultaneously measuring the five-DOF error motions of a linear stage up to one-meter travel with a linear error accuracy in sub-micrometer and an angular error accuracy in sub-arcsecond after compensation.