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1、精选优质文档-倾情为你奉上 毕业论文外文文献翻译 班级： 10机自3班 姓名： 易太平 学号： 2013 年 11 月 25 日专心-专注-专业Statistical investigation of hydraulic driven circular interpolation motionsAHMET MURAT PINAR1, ABDULKADIR GULLU2 and SEZAI TASKIN3,1Mechanical and Metal Technologies Department, Celal Bayar University,45400 Turgutlu-Manisa, Tur
2、key2Mechanical Education Department, Gazi University, 06500 Ankara, Turkey3Electrical and Electronics Engineering Department, Celal Bayar University,45140 Manisa, Turkeye-mail: ahmet.pinarcbu.edu.tr; agullugazi.edu.tr; MS received 30 October 2010; revised 3 August 2011; accepted 29 September 2011Abs
3、tract. In this study, a twin-axis gantry has been structured to examine hydraulic driven positioning skills of the curvilinear motions based on ISO 230-4 standard enti-tled Circular tests for numerically controlled machine tools. The system is controlled by a path and position control module of a PL
4、C device. As a result of the exper-iments conducted based on the full factorial design, the effects of piston diameter,feed rate, radius and their two-way interactions on the circularity error are determined through analysis of variance. Accordingly, minimum circularity error is obtained with the pi
5、ston diameter of 63 mm, inertia load of 12.5 kg, radius of 5 mm and feed rate of 50 mm/min as 0.345 mm. Circularity error increases with the increase of inertia load, radius and feed rate, and declines with the increase of piston diameter. Lastly, piston diameter has the greatest effect on the circu
6、larity error change and followed by radius,feed rate, piston diameterradius, radiusfeed rate, piston diameter-feed-rate, inertia load, piston diameterinertia load, and inertia loadradius factors and interactions.Keywords. CNC; circularity error; circular interpolation motion; hydraulic positioning;A
7、NOVA.1. IntroductionThe latest innovation point in speed and position control of machine tools in manufacturing technology is called as computer numerical control (CNC) technologies. The most important characteristics of these technologies are the machining tolerance in micron accuracy and manu-fact
8、uring the sculptured geometries that can not be machined via classical machines. The closed loop control of the systems with servo motor and ball screws through measuring components such as encoder enable these machines work precisely. In contrast, the hydraulic systems that have the advantages of f
9、ast response speed, very high system stiffness, higher force to weight ratio and compact size lose their robustness due to nonlinear parameters such as temperature,compressibility leakages, weight and friction, which are difficult to model. Therefore, hydraulic systems are used in the sub-operations
10、 of these machines such as tail stock and tool change mechanisms. Adaptive control and variable structure control (VSC) are the two most common approaches used to compensate for the nonlinear behaviour of hydraulic servo systems. Most of the adaptive controllers (Shih & Sheu1991; Bobrow & Lum 1995;H
11、oriet al1989; Plummer & Vaughan 1996;Lee &Srinivasan1990) use a linearized model for the system, and therefore provide only local stability. These systems can handle changing system parameters such as flow constants, fluid bulk modulus, and variable loading. The drawback of these linearized adaptive
12、 controllers is the lack of a global stability proof (Sohl & Bobrow1999). Although the classic VSC (Chern & Wu1991; Lee & Lee 1990;Hwang&Lan1994)is robust against external disturbances and parameter variations, it results in chattering leading to component damage and high control activity. Chatterin
13、g in VSC system is divided into two types such as chattering at VSC output and the chattering of state variables in state space. These two types of chattering have different nature and are from different sources (Hung1993). Although there are various solution methods to this problem in the literatur
14、e, the continuous methods, called as varying boundary layer (Hwang1996;Chenet al2005) and reaching law (Gao & Hung1993; Jerouaneet al2004; Hung & Hung1994) approaches, focus on the chattering on the VSC output, and the switching gain method (Hwang1996;Wanget al1996;Haet al1999;Yau2004;Hung & Chung20
15、07) on chattering of state variables. The literature survey has revealed that CNC technologies are not used widely in the control of hydraulic systems but used for the positioning accuracy of linear motions investigation. Altintas &Lane(1997) carried out the single axis motion of two cylinders of press brake via open archi-tecture CNC. Similarly, Pinar & Gll (2010) statistically examined the positioning accuracy of the linear motion of two-axis hydraulic gantry. The optimization of the system a
