運動學(xué)特性約束下曲面高速進給數(shù)控加工軌跡規(guī)劃
發(fā)布時間：2018-11-03 09:41
【摘要】：曲面數(shù)控高速、高效加工是機械制造不懈的追求。隨著進給速度的提高,由于加工曲面輪廓的復(fù)雜性,機床運動軸的運動劇烈,會使得機床產(chǎn)生振動與沖擊,直接影響著曲面加工質(zhì)量,嚴(yán)重甚至破壞機床的內(nèi)部結(jié)構(gòu)。本文針對曲面高速進給數(shù)控加工中機床運動軸的運動學(xué)特性超出機床限制的問題,提出一種運動學(xué)特性約束下的曲面加工軌跡規(guī)劃方法。主要思路是在考慮各軸運動學(xué)特性約束的基礎(chǔ)上,通過分析加工軌跡與機床運動軸的運動特性之間的關(guān)系,結(jié)合曲面加工方式,對高速進給加工下曲面的刀位軌跡規(guī)劃展開研究,從而最終在保證加工效率的同時,使加工過程中機床運動軸的運動更加平穩(wěn),不發(fā)生振動與沖擊,提高曲面加工質(zhì)量。主要工作如下:(1)機床的運動學(xué)特性分析。在對五軸數(shù)控機床進行運動學(xué)變換的基礎(chǔ)上,推導(dǎo)出刀位數(shù)據(jù)與機床各軸運動坐標(biāo)的數(shù)學(xué)關(guān)系。深入分析五軸數(shù)控加工過程中機床的運動學(xué)特性,給出運動學(xué)特性參量的計算方法以及加工軌跡規(guī)劃的運動學(xué)特性約束條件,并估算機床各軸允許的運動學(xué)特性約束值。(2)運動學(xué)特性約束下的刀位點確定。針對類回轉(zhuǎn)體曲面,以螺旋線導(dǎo)動法生成的刀位點和切觸點為基礎(chǔ),利用B樣條曲線對生成的初始切觸點軌跡進行擬合,考慮機床各軸的運動學(xué)特性及其曲面加工誤差,計算最終切觸點軌跡。分析B樣條曲線上切觸點與節(jié)點的對應(yīng)性,提出利用初始切觸點處的初始法矢量插值獲得最終法矢量的方法,進而完成刀位點的重新確定。(3)運動學(xué)特性約束下的刀軸矢量規(guī)劃�；谝阎牡段稽c軌跡,首先考慮速度特性約束,對刀軸矢量與機床運動軸速度的關(guān)系展開分析,提出一種滿足速度特性約束條件的刀軸矢量規(guī)劃方法,并對機床進給速度進行一定調(diào)整;其次,分析運動軸的加速度特性,以考慮速度特性的刀軸矢量規(guī)劃為基礎(chǔ),建立數(shù)學(xué)優(yōu)化模型,優(yōu)化確定最終的刀軸矢量,調(diào)整機床進給速度;然后,對個別加加速度超限刀位點處的機床進給速度進行調(diào)整,保證加加速度也滿足運動學(xué)特性約束條件。最后給出算例理論驗證刀軸矢量規(guī)劃方法的有效性。(4)鞋楦五軸加工與加速度測量實驗。以鞋楦曲面的高速五軸數(shù)控加工為例,經(jīng)過后置處理編寫數(shù)控加工程序,在五軸數(shù)控機床上展開精加工實驗,并同時進行加速度測量實驗。分析實驗結(jié)果,驗證本文所提出的運動學(xué)特性參量理論計算方法的正確性以及加工軌跡規(guī)劃方法的有效性。
[Abstract]:Surface NC high-speed and high-efficiency machining is the unremitting pursuit of mechanical manufacturing. With the increase of feed speed, because of the complexity of machining curved surface contour and the violent movement of machine tool axis, the machine tool will produce vibration and impact, which will directly affect the quality of curved surface machining and even destroy the internal structure of the machine tool seriously. In order to solve the problem that the kinematic characteristics of the moving axis of the machine tool exceed the limit of the machine tool in the high-speed feed NC machining of curved surface, this paper presents a trajectory planning method for the curved surface machining under the constraint of the kinematic characteristics. On the basis of considering the constraints of the kinematics characteristics of each axis, the main idea is to analyze the relationship between the machining track and the kinematic characteristics of the moving axis of the machine tool, and to combine the machining method of the curved surface. In this paper, the tool path planning of the curved surface under high-speed feed machining is studied, so as to ensure the machining efficiency, make the movement of the moving shaft of the machine tool more stable, avoid vibration and impact, and improve the machining quality of the curved surface at the same time. The main work is as follows: (1) Kinematic characteristics of machine tools are analyzed. On the basis of kinematic transformation of five-axis NC machine tool, the mathematical relation between the tool position data and the coordinate of each axis of the machine tool is deduced. The kinematics characteristics of the machine tool in the process of five-axis NC machining are deeply analyzed. The calculation method of kinematics characteristic parameter and the constraint condition of kinematics characteristic of machining path planning are given. The allowable constraint values of kinematic characteristics of each axis of the machine tool are estimated. (2) the tool location is determined under the constraint of kinematic characteristics. Based on the cutter position and tangent contact generated by helical lead method, the initial tangent contact trajectory is fitted by B-spline curve, and the kinematics characteristics of each axis of the machine tool and the machining error of the curved surface are considered. The final tangent contact trajectory is calculated. The correspondence between the tangent contact and the node on the B-spline curve is analyzed, and the method of obtaining the final normal vector by using the initial normal vector interpolation at the initial tangent contact is proposed. Then the tool location is redetermined. (3) the tool axis vector programming under the constraint of kinematics characteristics. Based on the known tool locus trajectory, the relationship between the cutter axis vector and the velocity of the moving axis of the machine tool is analyzed, and a tool axis vector programming method satisfying the constraint condition of the speed characteristic is proposed. The feed speed of the machine tool is adjusted to a certain extent. Secondly, the acceleration characteristic of the moving shaft is analyzed. Based on the vector programming of the tool shaft considering the velocity characteristic, the mathematical optimization model is established, the final tool axis vector is optimized and the feed speed of the machine tool is adjusted. Then, the feeding speed of individual machine tools with acceleration exceeding the limit is adjusted to ensure that the addition speed also meets the constraint condition of kinematics characteristics. Finally, an example is given to verify the effectiveness of the tool shaft vector programming method. (4) the experiment of shoe last five-axis machining and acceleration measurement. Taking the high speed five-axis NC machining of shoe last surface as an example, the NC machining program is compiled after post-processing, and the finishing experiment is carried out on the five-axis NC machine tool, and the acceleration measurement experiment is carried out at the same time. The experimental results verify the correctness of the theoretical calculation method of kinematic characteristic parameters and the validity of the machining trajectory planning method.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG659
本文編號：2307417
[Abstract]:Surface NC high-speed and high-efficiency machining is the unremitting pursuit of mechanical manufacturing. With the increase of feed speed, because of the complexity of machining curved surface contour and the violent movement of machine tool axis, the machine tool will produce vibration and impact, which will directly affect the quality of curved surface machining and even destroy the internal structure of the machine tool seriously. In order to solve the problem that the kinematic characteristics of the moving axis of the machine tool exceed the limit of the machine tool in the high-speed feed NC machining of curved surface, this paper presents a trajectory planning method for the curved surface machining under the constraint of the kinematic characteristics. On the basis of considering the constraints of the kinematics characteristics of each axis, the main idea is to analyze the relationship between the machining track and the kinematic characteristics of the moving axis of the machine tool, and to combine the machining method of the curved surface. In this paper, the tool path planning of the curved surface under high-speed feed machining is studied, so as to ensure the machining efficiency, make the movement of the moving shaft of the machine tool more stable, avoid vibration and impact, and improve the machining quality of the curved surface at the same time. The main work is as follows: (1) Kinematic characteristics of machine tools are analyzed. On the basis of kinematic transformation of five-axis NC machine tool, the mathematical relation between the tool position data and the coordinate of each axis of the machine tool is deduced. The kinematics characteristics of the machine tool in the process of five-axis NC machining are deeply analyzed. The calculation method of kinematics characteristic parameter and the constraint condition of kinematics characteristic of machining path planning are given. The allowable constraint values of kinematic characteristics of each axis of the machine tool are estimated. (2) the tool location is determined under the constraint of kinematic characteristics. Based on the cutter position and tangent contact generated by helical lead method, the initial tangent contact trajectory is fitted by B-spline curve, and the kinematics characteristics of each axis of the machine tool and the machining error of the curved surface are considered. The final tangent contact trajectory is calculated. The correspondence between the tangent contact and the node on the B-spline curve is analyzed, and the method of obtaining the final normal vector by using the initial normal vector interpolation at the initial tangent contact is proposed. Then the tool location is redetermined. (3) the tool axis vector programming under the constraint of kinematics characteristics. Based on the known tool locus trajectory, the relationship between the cutter axis vector and the velocity of the moving axis of the machine tool is analyzed, and a tool axis vector programming method satisfying the constraint condition of the speed characteristic is proposed. The feed speed of the machine tool is adjusted to a certain extent. Secondly, the acceleration characteristic of the moving shaft is analyzed. Based on the vector programming of the tool shaft considering the velocity characteristic, the mathematical optimization model is established, the final tool axis vector is optimized and the feed speed of the machine tool is adjusted. Then, the feeding speed of individual machine tools with acceleration exceeding the limit is adjusted to ensure that the addition speed also meets the constraint condition of kinematics characteristics. Finally, an example is given to verify the effectiveness of the tool shaft vector programming method. (4) the experiment of shoe last five-axis machining and acceleration measurement. Taking the high speed five-axis NC machining of shoe last surface as an example, the NC machining program is compiled after post-processing, and the finishing experiment is carried out on the five-axis NC machine tool, and the acceleration measurement experiment is carried out at the same time. The experimental results verify the correctness of the theoretical calculation method of kinematic characteristic parameters and the validity of the machining trajectory planning method.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG659
【參考文獻】
相關(guān)期刊論文 前10條
1 李忠新;黃川;劉延友;;高速切削加工關(guān)鍵技術(shù)及發(fā)展方向[J];中國工程機械學(xué)報;2014年01期
2 崔小順;魏建峰;魏紅港;楊程;;五軸數(shù)控加工非線性誤差控制策略及影響因素的研究[J];制造技術(shù)與機床;2013年11期
3 蔡永林;趙明波;王恒;;類回轉(zhuǎn)體曲面數(shù)控加工刀位軌跡規(guī)劃[J];機械工程學(xué)報;2013年21期
4 章永年;趙東標(biāo);陸永華;劉凱;;平底刀最優(yōu)刀軸矢量規(guī)劃算法[J];機械工程學(xué)報;2012年05期
5 張立強;王克用;王宇晗;;復(fù)雜曲面五軸側(cè)銑加工的運動學(xué)優(yōu)化方法[J];中國機械工程;2011年21期
6 鄧朝暉;劉戰(zhàn)強;張曉紅;;高速高效加工領(lǐng)域科學(xué)技術(shù)發(fā)展研究[J];機械工程學(xué)報;2010年23期
7 畢慶貞;王宇晗;朱利民;丁漢;;刀觸點網(wǎng)格上整體光順五軸數(shù)控加工刀軸方向的模型與算法[J];中國科學(xué):技術(shù)科學(xué);2010年10期
8 丁漢;畢慶貞;朱利民;熊有倫;;五軸數(shù)控加工的刀具路徑規(guī)劃與動力學(xué)仿真[J];科學(xué)通報;2010年25期
9 徐金亭;劉偉軍;邱曉杰;夏仁波;;自由曲面加工中的等參數(shù)螺旋軌跡生成方法[J];機械工程學(xué)報;2010年03期
10 陳曉兵;廖文和;吳海兵;孫全平;陳前亮;;三角網(wǎng)格表面等殘留高度刀軌生成算法[J];計算機輔助設(shè)計與圖形學(xué)學(xué)報;2009年12期
相關(guān)博士學(xué)位論文 前2條
1 黃澤華;整體葉輪銑削加工彈性變形預(yù)測及誤差補償研究[D];北京交通大學(xué);2013年
2 姜華;高速精密臥式加工中心開發(fā)的關(guān)鍵技術(shù)研究[D];四川大學(xué);2007年
相關(guān)碩士學(xué)位論文 前2條
1 馬燁萌;冗余自由度下曲面高速進給數(shù)控加工機床軸運動研究[D];北京交通大學(xué);2016年
2 楊智敏;動力學(xué)特性約束下葉輪數(shù)控加工刀位軌跡規(guī)劃[D];北京交通大學(xué);2014年
，本文編號：2307417
本文鏈接：http://sikaile.net/kejilunwen/jiagonggongyi/2307417.html
最近更新
教材專著
