Assessing geometrical errors of multi-axis machines by three-dimensional length measurements

In this paper a method is presented for assessing geometrical errors of mul ti-axis machines based on volumetric three-dimensional length measurements. A universal machine error model is proposed since a large variety of machi ne configurations exists. Such models can be used for software error compen sation techniques in order to improve the machine's positioning behaviour a s well as for diagnostic purposes. Length measurements are chosen for the m easurement of the positioning errors of a multi-axis machine because these measurements can be executed in a short period of time in U relatively simp le way combined with a high accuracy. In order to get comparable results fo r the geometrical errors as measured with conventional techniques, i.e., la ser interferometry, the design of the measurement setup as well as the form ulation of the machine error model (including parameter correlation effects ) appeared to be of major importance and are subject of this paper. (C) 200 1 Elsevier Science Ltd. All rights reserved.