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1、Con.guration analysis of .ve-axis machine tools using a generic kinematic modelO. Remus Tutunea-Fatan, Hsi-Yung Feng _Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ont., Canada N6A 5B9Received 13 November 2003; received in revised form 4 February 2004Abst
2、ractFive-axis machine tools are designed in a large variety of kinematic con.gurations and structures. Regardless of the type of the intended analysis, a kinematic model of the machine tool has to be developed in order to determine the translational and rotational joint movements required to achieve
3、 a speci.ed position and orientation of the cutting tool relative to the workpiece. Ageneric and uni.ed model is developed in this study as a viable alternative to the particular solutions that are only applicable to individual machine con.gurations. This versatile model is then used to verify the f
4、easibility of the two rotational joints within the kinematic chain of three main types of .ve-axis machine tools: the spindle rotating, rotary table, and hybrid type. A numerical measure of total translational joint movement is proposed to evaluate the kinematic performance of a .ve-axis machine too
5、l. The corresponding kinematic analyses have con.rmed the advantages of the popular machine design that employs intersecting rotational axes and the common industrial practice during setup that minimizes the characteristic rotating arm length of the cutting tool and/or workpiece.# 2004 Elsevier Ltd.
6、 All rights reserved.Keywords: Con.guration analysis; Kinematic model; Machine design; Machine setup; Five-axis machine tool1. IntroductionFive-axis machining o.ers de.nite advantages over the more common three-axis machining process. Fiveaxis machine tools are often quoted for their increased produ
7、ctivity, accuracy and .exibility in contrast to the three-axis ones 1,2. Notable e.orts have been takingplace in recent years to overcome some of the inherent drawbacks of .ve-axis machines like more complex programming and post-processing, greater possibility of gouging and collision during cutting
8、, and higher machine costs. Despite these known shortcomings, more and more of these machines are being used in practice. The balance between positioning-only andcontinuous .ve-axis machining work has become more equilibrated lately than it was a few years ago 3. Most research studies on .ve-axis ma
9、chining have commonly identi.ed the need to develop a model to analyze the kinematic structure of the machine. There are several approaches proposed for this purpose, with some of them transferred from robotics research. One such approach, which is well known and extensively used, was introduced by
10、Denavit and Hartenberg 4 and later modi.ed by Paul 5. The concept of form shaping functions was also proposed for machine tool kinematic analyses 6. Some research studies only containedlimited development on this subject, as their focuses were more on other aspects of .ve- axis machining. Suh and Le
11、e 7 used the DenavitHartenberg representation to develop a versatile path planning method by which .ve-axis machining can be done by a three- axis machine and rotary table combination. Similar applications have resulted in an adaptive algorithm for tool path optimization 8 and a combined 3D linear a
12、nd circular interpolation technique for the .ve-axis machining of complex surfaces 9.The machining accuracy is a resultant of both internal and external factors acting on the cutting process. Evidently, the accuracy of the whole kinematic chain will have a direct in.uence on the overall machining pr
13、ecision. As a result, a number of studies attempted to establish relationships between the inaccuracy in the components of the kinematic chain and the resulting position and orientation error of the cutting tool. Oneof the early studies in this area was reported by Kiridena and Ferreira 10. They sug
14、gested a method to outline the e.ects of positioning errors of machine axes on the cutting tool position and orientation in its workspace. Later, Mahbubur et al. 11 showed that the perpendicularity between the rotational axes of a .ve-axis machine signi.cantly a.ected the positioning error at the to
15、ol tip. Bohez 12 proposed a new general approach to compensate for systematic errors in a horizontal .ve-axis machine based on the closed loop volumetric error relations.The common point of almost all of the above-mentioned studies is the fact that a kinematic model of the machine is essential, as t
16、he position and orientation of the cutting tool, represented by the cutter location (CL) data and the tool axis vector, have to be converted into machine control coordinates (MCC) for inputting to the CNC machine controller. This conversion is commonly referred to as post-processing. Post-processing for .ve-axis machining is more complex than that for three-axis machining and many parameters requireattention when a full portab
