TH6340卧式加工中心十字滑台部件设计英文翻译与英文原文.庄-- 2.doc

武汉工业学院毕业设计（论文）外文参考文献译文本200 9届 译文出处 Peter Dransfield, Hydraulic Control System-Design and Analysis of Their Dynamics, Springer-Verlag, 1981 毕业设计(论文)题TH6340卧式加工中心十字滑台部件设计 院（系） 机械工程学院 专业名称 机械设计制造及其自动化 学生姓名 taoge 学生学号 090309727 指导教师 刘 海 岷 翻译文献：INVESTIGATION ON DYNAMIC PERFORMANCE OF SLIDE UNIT IN MODULAR MACHINE TOOL （对组合机床滑台动态性能的调查报告）文献作者：Peter Dransfield,出处： Peter Dransfield, Hydraulic Control System-Design and Analysis of Their Dynamics, Springer-Verlag, 1981INVESTIGATION ON DYNAMIC PERFORMANCE OF SLIDE UNIT IN MODULAR MACHINE TOOLThis paper deals with the investigation for slide units impact and motion stability in modular machine tool fay means of the method of power bond graph and state space analysis. The dynamic mathematical model of self-adjusting back pressure speed control system used to drive slide unit is established. Main reasons and affecting factors for slide unit impact and motion unstability are analysed through computer digital simulation, It is concluded from those that, if the structural dimensions of hydraulic cylinder and back pressure valve are designed rationally, the slide units dynamics will markedly be improved.During operation of modular machine tool, the changes of slid units speed and load acted on it in both magnitude and direction will affect working performar.ee to a different extent Particularly the impact caused by sudden vanishing of load and the motion instability due to periodical change of load in operation will affect the surface quality of the work piece machined, and the tool would be broken off under serious conditions, By using the method of power bond graph and state space analysis, the dynamic mathematical model of the system used to drive slide unit is established, that is called as self-adjusting back pressure speed control system and abbreviated to SABP system. In order to improve slide units dynamics, it is necessary to find out the main reasons and affecting factors, that must be based on computer digital simulation and study on the results.DYNAMIC MATHEMATICAL MODELThe schematic diagram of SABP system is shown , the system is used to perform the cycle of feeding, stopping and returning. Four ways control valve works in the right position during slide units feeding. The supply pressure of the pump is approximately constant under the action of pressure relief valve, the oil through the control valve and pressure compensated flow control valve enters the non-rod chamber to put slide unit forward. At the same time, the oil from the rod chamber is discharged through SABP valve and directional control valve to tank. In this process, the state of two check valves and pressure relief valve is not changed, To establish the mathematical model as reasonably and simply as possible, consideration must be focused on main affecting factors for a complex non-linear system such as the SABP system. It is illustrated by theoretical analysis and test result , that the transient time of the system is much longer than that of the flow control valve, and the flowrate overshoot of the valve in transients affects very small to slide unit speed because of the ;large effective sectional area of non-rod chamber in cylinder. For investigating the systems dynamics widely and deeply, the initial modeltn is further simplified in this paper, and so the study can be efficiently made with microcomputer. It is assumed that the flowrate through the flow control valve isConstant in the whole transient process, and is denoted to a flow source.Fig.2 shows the structure diagram of the dynamic model of the system, it is composed of cylinder, slide unit, SABP valve and pipe line; etc.By using the method of power bond graph and state space analysis in this paper, the dynamic mathematical model of the system is to be established- The power bond graph is a power flow diagram, which expresses abstractly the actions among sub-systems as three effects, i.e. resistance effect, capacitive effect and inertia effect, according to the way of energy transform, on the basis of practical structure and by means of method of lumped parameters. The model is characterized by a clear conception in physics, and non-linear system can be accurately analysed in combination with method of state space analysis, thus it is a effective method used in the dynamic investigation of complex non-linear system in the time domain.From main performances of components in SAEP system, the power bond graph of the system has been formed by means of the rule of model establishing and is shown in Fig.3. Half arrow in each bond indicates a direction of power How, two variahles of power are effort variable and flow variable. O-junction illustrates algebraic summation of flow variables at common effort, i.e. parallel connection; 1-junction does algebraic summation of effort variables at common flow, i.e. series connection. The symbol TF represents power transformer between two types of energy, and transforming modulus between efforts or flows is noted below the symbol TF. Short transverse bar across one end of each bond shows causality between two variables. A full arrow expresses a control action. Among three actions, there is an integration or differential form in capacitive effect and inertia effect between two variables. So state equation may be derived from Fig.3, there are nine state variables in this complex nonlinear equation. Studying on the slide units dynamics is started with impact and motion stability. The equation is simulated by using the method of 4th order Runge-Kutta integration procedure on IBM-PC computer. Fig.4 and Fig.5 illustrate the results respectively.SLIDE UNIT IMPACTSlide units impact phenomenon results from loads vanishing in the transients, for example, the situation of drilling through work piece, Fig.4 expounds the variations of the load and speed of slide unit, the pressures of chambers in cylinder. When slide unit motions evenly under the action of load, the oil pressure in non-rod chamber is very high, and there is a lot of hydraulic energy accumulated in side. The pressure decreases at once with loads discharging rapidly. During the process of oil pressure converting from high to low, the system absorbs some of the energy, so slide unit impacts forward with high speed. And then the oil in rod chamber is141compressed to increase back pressure, some of the energy is consumed, which plays a part of restraining the impact of the slide unit. It must be noted that inlet pressure of SABP valve telys on the interaction of pressures of two chambers, and increases rapidly at the instant of loads vanishing, and then stabilizes at some value greater than initial one. This pressure is also greater than one of traditional speed control system, therefore the energy can be absorbed much more in the rod chamber. In result, the impact of slide unit in SABP system is 20% lower than in traditionalism. It is thus clear that slide unit with SABP system for driving has a good performance in restraining the impact and SABP valve plays an important part in that,MOTION STABILITYWhen load acting on slide unit varies periodically, such as the situation of milling, slide units speed will bring about some pulse. In order to meet the requirements of manufacturing quality, the magnitude of the speed pulse must be reduced as small as possible. The variation of the load is assumed to be of sine wave, in order to simplify discussion of the problem. The result of digital simulation is shown in Fig.5 It can be seen that, the response of the system is the sambas traditions and the differences between them are very small. The reason for this is that the variation of the load is not target, there the pressures in chambers vary very little that is, and the effect of the SABP valve is not obvious.IMPROVEMENTIt is shown by studying, that dynamics of slide unit which used SABP speed control system as driving system is better than that of traditional system. To reduce the slide units impact, the back pressure of rod chamber has to be increased rapidly in the transients of loads vanishing; on the other hand, to enhance the slide units motion stability, it is necessary to raise the system rigidity. However, main recommendation lies in decreasing the volume of oil. It is known from system structure that, there is a lot of oil-containing volume between the rod chamber and drain pipe as shown in Fig.6a. Because the volume exists, not only the effect of SABP valve is delayed and reduced, hut also the rigidity of the system is decreased. Therefore, it is hindered to further improve the impact and motion stability. To make the slide unit dynamics better, the structural dimensions of cylinders chamber and the SABP valve must be designed suitably. Based on simulations under the various structural dimensions and comparison among the results, the following two measures can be taken for improvements:the ratio between volumeV4 and V3 is changed from 5.5 to 1 approximately, as shown in Fig,6b;142the bottom diameter of spool of the SABP valve is increased from 10 mm to 13 mm and .the length of side of triangular damping slot is decreased from 1 mm to 0.7mm the slide unites impact quantity can be reduced by 30%, and the time of dynamic response is shortened. In addition, slide units motion stability may be improved obviously. It is thus evident that improvements are very effective.CONCLUSIONSBy the way of theoretical analysis and computer simulating investigation, it is obvious that the SABP speed control system used as slide units driving system in modular machine tool is valuable for popularization and utilization, Main factors affecting the slide unit dynamics are the structural dimensions of the cylinder and the SABP valve. In the case of rationally designing, the slide unit dynamics may be obviously improved. Meanwhile, it is shown that the method of power bond graph and state space analysis is a very convenient and effective method in studying dynamics of complex non-linear hydraulic system.翻译文献：INVESTIGATION ON DYNAMIC PERFORMANCE OF SLIDE UNIT IN MODULAR MACHINE TOOL （对组合机床滑台动态性能的调查报告）文献作者：Peter Grandfield,出处： Peter Grandfield, Hydraulic Control System-Design and Analysis of Their Dynamics, Springer-Velar, 1981l 英文译文： 对组合机床滑台动态性能的调查报告【摘要】这一张纸处理调查利用有束缚力的曲线图和状态空间分析法对组合机床滑台的滑动影响和运动平稳性问题进行分析与研究，从而建立了滑台的液压驱动系统一自调背压调速系统的动态数学模型。通过计算机数字仿真系统，分析了滑台产生滑动影响和运动不平稳的原因及主要影响因素。从那些中可以得出那样的结论，如果能合理地设计液压缸和自调背压调压阀的结构尺寸.本文中所使用的符号如下： s1-流源，即调速阀出口流量； Sel滑台滑动摩擦力 R一滑台等效粘性摩擦系数： I1滑台与油缸的质量 12自调背压阀阀心质量 C1、c2油缸无杆腔及有杆腔的液容； C2自调背压阀弹簧柔度； R1, R2自调背压阀阻尼孔液阻， R9自调背压阀阀口液阻 Se2自调背压阀弹簧的初始预紧力； I4, I5管路的等效液感 C5、C6管路的等效液容： R5, R7-管路的等效液阻； V3, V4油缸无杆腔及有杆腔内容积； P3, P4油缸无杆腔及有杆腔的压力 F滑台承受负载， V滑台运动速度。本文采用功率键合图和状态空间分折法建立系统的运动数学模型，滑台的动态特性可以能得到显著改善。一、引言 在组合机床正常工作中，滑台运动速度的大小和它的方向以及所承受负载的变化都将以程度不同地影响其工作性能。特别是在工进过程中。滑台上负载的突然消失引起的前进以及负载的周期性变化而引起的运动不平稳性，都将影响被加工件的表面质量，在严重的情况下会使刀具折断掉。根据大连机床厂要求，作者采用有束缚力的曲线图和状态空间分析法建立组合机床滑台的新型液压驱动系统一自调背压调速系统的动态数学模型。为了改善滑台的动态特性，有必要去分析找出滑台产生前冲和运动不平稳的原因以及主要的影响因素，但那必须通过计算机数字仿真和研究得出最后的结果。二、动态数学模型 组合机床滑台的液压驱动系统一自调背压调速系统的工作原理图如图I所示。这个系统是用来完成工进一停止一快退”的工作循环。当滑台在工进时，三位四通换向阀处于图示右位，油泵的供油压力在滥流阀的有效作用下近似地几乎保持恒定，该油液流经过换向阀和调速阀后进入油缸的无杆腔，以推动滑台向前移动；与此同时，从油缸有杆腔排出的压力油经自调背压阀和换向阀流回油箱了。在这个过程中，两个单向阀和溢流阀的工作状态始终都没有任何变化。对与象组合机床滑台的液压驱动系统一自调背压调速系统这样的复杂非线性的系统，为了便于研究它的动态特性，建立一个仅着重考虑主要影响因素的合理简单的动态数学模型是尤其重要的12。从理论分析和试验研究的列举中可以得知：该系统的过程时间是远大于调速阀的过程时间的，当油缸无杆腔有效承压面积很大时，调速阀出口流量的瞬时的超调反映为滑台运动速度的变化是很小的2。为了更加拓宽和深入研究系统的动态特性，使研究工作能在微型计算机上有效地进行，本文章对原模型2做进一步简化处理，假定调速阀在系统的整个通过过程中输出时候恒定的流量，这被看作其为流源。这样，系统的动态模型的结构简图如图2所示，它是由油缸、滑台，自凋背压阀和联接管路等组成。 功率键合图是一功效流图，它是按着系统的能量传递方式，以实际结构为基础，用集中参数把子系统之间的作用关系抽象地表示为阻性元R、容性元C和感性元I的三种作用元。采用这种方法建模物理概念清晰，结合状态空间分析法可以较准确地描述和分析线性系统，该方法在时域中研究复杂非线性系统动态特性的一种有效的方法。 根据自调背压调速系统各元件的主要特性和建模规则1，得出了图3所示的系统的功率键合图。图中每根键上的半箭头表示功率流向，构成功率的两个变量是力变量（油压P或作用力F）和流变量（流量q或速度v）。O结点表示在系统中属于并联连接，各键上的力变量相等而流变量之和为零；1结点表示在系统中属于串联连接，各键上流变量相等而力变量之和为零。TF表示不同能量形式间的变换器，TF下标注的字母表示力变量或流变量的转换比值。键上的短横杠表示该键上两变量间的因果关系。全箭头表示控制关系。在三种作用元中容性元和感性元的力变量与流变量之间具有积分或微分关系，因此，根据图3可推导出具有九个状态变量的复杂非线性状态方程。本文对滑台动态特性的研究是从滑台的前冲和运动平稳性两方面入手，用四阶定步长Rung