發(fā)布時間：2018-07-05 15:27

  本文選題：五軸數(shù)控機床 + 工作精度檢驗　； 參考：《電子科技大學(xué)》2015年博士論文

【摘要】：隨著現(xiàn)代制造技術(shù)的快速發(fā)展,數(shù)控機床已經(jīng)成為不可或缺的重要設(shè)備,而高速高精度五軸數(shù)控機床的應(yīng)用已經(jīng)成為提升制造業(yè)技術(shù)水平及高科技發(fā)展的重要標(biāo)志。在復(fù)雜零件的高速精密加工中,五軸數(shù)控機床的運動性能成為影響工件質(zhì)量的關(guān)鍵因素和機床等級評價的重要指標(biāo)。通過切削試件輪廓誤差的表現(xiàn)反映運動控制指標(biāo)的作用度,以指導(dǎo)機床調(diào)整和工藝優(yōu)化,保障五軸數(shù)控機床最終加工精度有著十分重要意義。本文從數(shù)控機床的工作精度檢驗標(biāo)準(zhǔn)出發(fā),對五軸數(shù)控機床加工過程中的輪廓誤差形成機理,數(shù)控機床伺服特性和控制系統(tǒng)的控制特性對運動軌跡、運動性能和加工精度的影響進行了研究。采用一種基于前瞻算法的多軸運動的軸速度規(guī)劃策略,建立了五軸聯(lián)動數(shù)控機床運動控制參數(shù)影響試件切削速度、加速度以及加工精度的模型,揭示了試件在高速高精度加工中異常刀痕形成機理,探索了多軸聯(lián)動高速加工數(shù)控機床工作性能評價新途徑,為利用復(fù)雜形面試切結(jié)果評價數(shù)控機床的工作性能提供了理論依據(jù)。研究過程中主要開展了以下幾個方面的工作并得到相關(guān)的研究成果。(1)論文首先研究了五軸數(shù)控加工中的試件輪廓誤差形成機理,分析了數(shù)控機床加工誤差的主要來源,論述了五軸數(shù)控機床的軸跟隨誤差對試件輪廓誤差形成的作用機理。針對五軸數(shù)控機床由于旋轉(zhuǎn)軸的引入導(dǎo)致的刀尖運動軌跡的復(fù)雜變化,運用了多體運動理論以及齊次坐標(biāo)變換理論,推導(dǎo)了五軸數(shù)控加工中的復(fù)雜形面的軸跟隨誤差與輪廓誤差的映射關(guān)系。(2)由于數(shù)控機床的伺服特性是影響單軸跟隨誤差的主要因素,本文根據(jù)數(shù)控機床的平動軸、旋轉(zhuǎn)軸伺服驅(qū)動裝置和機械傳動機構(gòu)的結(jié)構(gòu)特點,建立了這兩種形式的伺服機構(gòu)動力學(xué)模型,研究數(shù)控機床伺服性能指標(biāo)對各坐標(biāo)軸誤差的影響,特別是旋轉(zhuǎn)軸伺服特性對輪廓誤差的影響。針對工作精度檢驗中常見的圓弧軌跡的多軸聯(lián)動運動情況,分別對平動軸與旋轉(zhuǎn)軸聯(lián)動、兩個旋轉(zhuǎn)軸聯(lián)動兩種聯(lián)動方式進行了討論,從伺服系統(tǒng)的剛度、增益、伺服時間常數(shù)、反向間隙等指標(biāo)對輪廓誤差的影響以及各軸參數(shù)之間匹配關(guān)系進行了系統(tǒng)的分析。(3)研究了數(shù)控系統(tǒng)的控制方法、運動極限參數(shù)對坐標(biāo)軸誤差的影響。由于坐標(biāo)軸跟隨誤差與軸運動速度相關(guān),即受坐標(biāo)軸指令值的直接影響,而坐標(biāo)軸指令又受數(shù)控系統(tǒng)插補算法,加減速控制方式及運動極限參數(shù),前瞻算法等多因素影響,使得伺服系統(tǒng)接收的各坐標(biāo)軸指令與編程的G代碼指令有較大不同,不能簡單按照試件成形機理分解成各坐標(biāo)軸指令,因此,本文采用了一種動態(tài)規(guī)劃的進給速度規(guī)劃策略來計算坐標(biāo)軸指令,對高速高精度復(fù)雜形面加工中,微小段多,轉(zhuǎn)折和拐點多等情況下的進給速度實施規(guī)劃和軸指令值的求解,并分析了控制系統(tǒng)加速度、加加速度、最大速度等極限參數(shù)對軸進給速度和軌跡運動誤差的影響,以及這些極限參數(shù)的作用權(quán)重,從而建立高速加工中數(shù)控機床的控制指標(biāo)影響復(fù)雜曲面輪廓誤差的理論體系。(4)針對工作精度檢驗中常用的國際標(biāo)準(zhǔn)NAS試件和“S”形試件的試件切削檢驗中的運動軌跡誤差進行了計算、仿真和實驗設(shè)計,研究了數(shù)控機床實際運動性能的表現(xiàn),以及運動控制指標(biāo)對加工精度的影響。通過NAS試件的仿真切削研究,分析了試件加工精度所映射的多軸聯(lián)動機床伺服性能指標(biāo)和運動控制指標(biāo)作用規(guī)律;以“S”形試件側(cè)銑加工的過程為研究對象,從試件構(gòu)造的曲面特性出發(fā),分析了五軸數(shù)控加工的編程代碼特點,對側(cè)銑加工表面切削速度受數(shù)控機床的加速度、加加速度等運動控制參數(shù)影響的平穩(wěn)性進行了分析,通過伺服進給系統(tǒng)模型獲得跟隨誤差,并對側(cè)銑加工的異常刀痕的形成進行了演繹。通過仿真和實驗,得到“S”形試件側(cè)銑加工異常刀痕的機床運動控制指標(biāo)作用規(guī)律,為數(shù)控機床工作精度檢驗中試件構(gòu)造設(shè)計和利用試件切削誤差來檢驗機床運動性能提供參考依據(jù)。本課題來源于國家04重大科技專項“國產(chǎn)高檔數(shù)控機床在典型飛機結(jié)構(gòu)件加工中的示范應(yīng)用”,項目編號2010ZX04015-011,課題研究成果部分用于校驗機床的運動性能,指導(dǎo)機床維修和調(diào)整,優(yōu)化加工方案;同時為制定五軸數(shù)控加工動態(tài)精度測試規(guī)范,為高速高精度五軸聯(lián)動數(shù)控機床的研制和工作性能分析提供理論依據(jù)。
[Abstract]:With the rapid development of modern manufacturing technology, CNC machine tool has become an indispensable important equipment, and the application of high speed and high precision five axis CNC machine tool has become an important symbol to improve the technology level of manufacturing industry and the development of high technology. In the high speed precision machining of complex parts, the motion performance of five axis CNC machine tool has become the influence worker. The key factor of the quality of the parts and the important index of the evaluation of the machine tool grade. It is very important to guide the adjustment of the machine tool and the process optimization by the representation of the contour error of the cutting specimen, to guide the adjustment of the machine tool and the process optimization, and to ensure the final machining precision of the five axis CNC machine tools. The formation mechanism of the contour error in the processing of five axis CNC machine tools, the influence of the servo characteristics and control characteristics of the CNC machine tools on the motion trajectory, the motion performance and the machining precision are studied. The motion control of the five axis CNC machine tool is established by using a multi axis motion planning strategy based on the forward looking algorithm. The model of the parameters affecting the cutting speed, acceleration and machining precision reveals the formation mechanism of the abnormal knife marks in high speed and high precision machining, explores a new way to evaluate the performance of the CNC machine tools with multi axis linkage and high-speed machining, and provides a theoretical basis for the evaluation of the working performance of the CNC machine tool by using the results of complex interviewing and cutting. The following work is carried out in the following aspects and the relevant research results are carried out. (1) first, the paper studies the formation mechanism of the profile error in the five axis NC machining, analyzes the main source of the machining error of the NC machine tool, and discusses the action machine of the axis following error of the five axis NC machine tool to the outline error of the specimen. In view of the complicated changes in the trajectory of the blade tip caused by the introduction of the rotating axis in the five axis CNC machine tool, the multi body motion theory and the homogeneous coordinate transformation theory are applied to deduce the mapping relation between the axis following error and the contour error of the complex surface in the five axis NC machining. (2) the servo characteristics of the CNC machine tool are the single axis. Following the main factors of the error, based on the structural characteristics of the translational axis, the rotating shaft servo drive device and the mechanical transmission mechanism of the CNC machine tools, the dynamic model of the two forms of servo mechanism is established, and the influence of the servo performance index on the coordinate axis error is studied, especially the rotation axis servo characteristics to the contour error. In view of the multi axis linkage movement of the common circular arc trajectory in the work precision test, the linkage between the translational axis and the rotating axis and the two linkage modes of the two rotation axes are discussed respectively. The influence of the stiffness, gain, servo time constant and reverse clearance on the contour error and the matching of the parameters of the axis of the servo system are discussed. The system analysis is carried out. (3) the control method of numerical control system is studied, and the influence of the motion limit parameters on the coordinate axis error is studied. The coordinate axis following error is related to the axis motion speed, that is, the direct influence of the coordinate axis instruction value, and the coordinate axis instruction is also affected by the numerical control system interpolation algorithm, the acceleration and deceleration control mode and the motion limit. With the influence of many factors, such as parameters and forward looking algorithms, the coordinate axis commands received by the servo system are different from the programmed G code instructions. It can not be simply divided into coordinate axis instructions according to the forming mechanism of the specimen. Therefore, a dynamic programming strategy of feed speed planning is adopted to calculate the coordinate axis instruction, and the high speed and high precision is used in this paper. In the processing of complex surface, the feed speed under the circumstances of many small segments, turning points and many turning points is solved, and the influence of the limit parameters such as acceleration, adding speed and maximum velocity on the axis feed speed and track motion error are analyzed, and the action weight of these limit parameters is established, and the high speed is established. The control index of NC machine tool in processing affects the theory system of the contour error of complex curved surface. (4) calculation, simulation and experimental design are carried out for the motion trajectory error of the test parts of the international standard NAS test parts and the "S" shaped specimen, which are commonly used in the inspection of the work precision. The simulation and experimental design are designed, and the performance of the actual motion performance of the NC machine tool is studied and the performance of the numerical control machine is studied. The influence of the motion control index on the machining precision. Through the simulation cutting research of the NAS specimen, the servo performance index and the motion control index of the multi axis linkage machine tool mapped by the test parts are analyzed. The process of the side milling of the "S" shaped specimen is taken as the research object, and the five axis is analyzed from the surface characteristics of the specimen structure. The programming code characteristics of NC machining are analyzed. The stability of the cutting speed of side milling is influenced by the acceleration of CNC machine tools, adding speed and other motion control parameters. The following error is obtained by the servo feed system model, and the formation of abnormal knife marks in the side milling process is deducted. The simulation and experiment results are obtained. The action rule of the motion control index of the machine tool of "S" shaped specimen with abnormal knife marks is provided for the structural design of the test parts of the CNC machine tool and the use of the cutting error to test the motion performance of the machine tool. This topic is derived from the national 04 major science and technology special machine tool in the typical aircraft structure. The project number 2010ZX04015-011, the project number is used to verify the motion performance of the machine tool, to guide the maintenance and adjustment of the machine tool, to optimize the processing scheme, and to formulate the dynamic precision test specification for the five axis NC machining, and to analyze the development and performance analysis of the high speed and high precision five axis CNC machine tool. For theoretical basis.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TG659
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本文編號：2100703