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畢業(yè)設計(論文)開題報告
題目 萬向節(jié)滑動叉機加工藝及工裝設計
專 業(yè) 名 稱 機械設計制造及其自動化
班 級 學 號 05031318
學 生 姓 名 伍峰
指 導 教 師 焦益群
填 表 日 期 2009 年 2 月 18 日
一、選題的依據(jù)及意義:
在工程機械和汽車的傳動裝置中,由于總體布置上的需要,都要用到萬向傳動裝置。它的功用主要是在兩軸不同心或有一定夾角的軸間傳遞動力,在工作中相對位置不斷發(fā)生變化的兩軸間傳遞動力。萬向傳動裝置一般是由萬向節(jié)和傳動軸組成,有時還要有中間支承,主要用于以下一些位置:
發(fā)動機前置后輪驅(qū)動汽車(見圖D-C4-1(a))的變速器與驅(qū)動橋之間。當變速器與驅(qū)動橋之間距離較遠時,應將傳動軸分成兩段甚至多段,并加設中間支承。
多軸驅(qū)動的汽車的分動器與驅(qū)動橋之間或驅(qū)動橋與驅(qū)動橋之間 (見圖D-C4-1(b))。
由于車架的變形,會造成軸線間相互位置變化的兩傳動部件之間。 如圖D-C4-1(c)所示為在發(fā)動機與變速器之間。
采用獨立懸架的汽車的與差速器之間(見圖D-C4-1(d))。
轉(zhuǎn)向驅(qū)動車橋的差速器與車輪之間(見圖D-C4-1(e))。
汽車的動力輸出裝置和轉(zhuǎn)向操縱機構(gòu)中(見圖D-C4-1(f))。
萬向節(jié)是實現(xiàn)變角度動力傳遞的機件,用于需要改變傳動軸線方向的地方。
傳動軸是萬向傳動裝置的組成部分之一,這種軸一般長度較長,轉(zhuǎn)速高;并且由于所連接的部件(如變速箱與驅(qū)動橋)間的相對位置經(jīng)常變化,因而要求傳動軸長度也要相應地有所變化,以保證正常運轉(zhuǎn),這就要用到滑動花鍵副?;瑒踊ㄦI副由內(nèi)、外花鍵組成,在工作時滑動副之間的伸縮運動來實現(xiàn)距離變化,用于傳遞長度的變化。
萬向節(jié)滑動叉就是將萬向節(jié)叉和滑動花鍵副的一部分組合起來,使其成為一個零件,其特征是該萬向節(jié)滑動叉為采用管材制作的萬向節(jié)叉與滑動套為一體的整體式結(jié)構(gòu),其端部呈叉形結(jié)構(gòu),并設有兩個十字銷孔,用于安裝十字萬向節(jié);在管內(nèi)設有內(nèi)花鍵,這種呈整體式結(jié)構(gòu)的滑動叉,不僅加工容易、成本低,而且強度高,故其使用壽命與傳統(tǒng)的萬向節(jié)叉滑動套合件相比,有了成倍的提高。它的研究和使用可以簡化萬向傳動裝置的結(jié)構(gòu),也滿足功能要求,因此對萬向節(jié)滑動叉的研究有極大的實際意義。
二、國內(nèi)外研究概況及發(fā)展趨勢(含文獻綜述):
十字軸式剛性萬向節(jié)具有結(jié)構(gòu)簡單,傳動效率高的優(yōu)點,但在兩軸夾角α不為零的情況下,不能傳遞等角速轉(zhuǎn)動。主要用于傳遞角度的變化,一般由突緣叉、十字軸帶滾針軸承總成、萬向節(jié)叉或滑動叉或花鍵軸叉、滾針軸承的軸向固定件等組成。萬向節(jié)叉是一個叉形零件,一般采用中碳鋼或中碳合金鋼的鍛造件,也有采用中碳鋼的精密鑄造件。
汽車工業(yè)的發(fā)展對高品質(zhì)、低成本鍛件的需求不斷上升。轉(zhuǎn)向萬向節(jié)滑動叉(如圖1所示)是一個重要的汽車零件,其形狀復雜,尺寸精度和形位公差要求高,鍛造工藝性差。目前,國內(nèi)各主要鍛造廠主要采用開式模鍛工藝進行生產(chǎn),鍛件成形質(zhì)量差,材料利用率低。因此迫切需要一種新的加工工藝,以提高成形質(zhì)量,減少材料浪費,降低成本。
圖1 滑動叉鍛件???
滑動叉?zhèn)鹘y(tǒng)上采用的開式模鍛工藝生產(chǎn),飛邊大,材料浪費嚴重且尺寸精度差。為了降低鍛件成本,針對滑動叉的形狀特征,又提出了一些先進的工藝方案,比如一種少無飛邊模鍛的新工藝,使預制毛坯在封閉的模膛內(nèi)成形,實現(xiàn)鍛件近凈成形。根據(jù)體積不變原則對
圖2 開式與無飛邊閉式模鍛工藝對比???
計算毛坯進行處理得到預制毛坯。
如圖1所示的滑動叉形狀復雜,而且叉桿部截面呈圓形,傳統(tǒng)的整體閉式模鍛工藝難以實現(xiàn)無飛邊鍛造。在研究傳統(tǒng)無飛邊鍛造工藝和擠壓工藝的基礎(chǔ)上,開發(fā)了滑動叉無飛邊閉式模鍛新工藝,以滿足滑動叉的無飛邊鍛造的要求。
無飛邊鍛造工藝是一種先進的鍛造工藝,通常用于高品質(zhì)鍛件的生產(chǎn)。如圖2所示,與有飛邊鍛造工藝相比,無飛邊鍛造工藝中鍛件在封閉的模腔內(nèi)成形,不產(chǎn)生飛邊,節(jié)省材料,成形精度高,可實現(xiàn)鍛件的近凈成形或凈成形。
有限元模擬研究表明,與開式模鍛工藝相比,無飛邊和小飛邊閉式模鍛新工藝具有鍛件精度高、成形質(zhì)量好、材料利用率高、所需設備噸位小等優(yōu)點,具有很好的工業(yè)應用前景。
三、研究內(nèi)容及實驗方案:
本次畢業(yè)設計的主要內(nèi)容是繪制萬向節(jié)滑動叉零件圖并編制其機械加工工藝規(guī)程。對典型的工序設計專用夾具,并繪制專用夾具裝配圖1~2套和專用夾具的主要零件圖。
在說明書中詳細地說明了成批大量生產(chǎn)某解放牌汽車底盤傳動軸上的萬向節(jié)滑動叉的工藝規(guī)程的制定過程。
1.查閱資料,英文資料翻譯(6000字),開題報告
2.繪制萬向節(jié)滑動叉零件圖并編制其機械加工工藝規(guī)程一份
3.設計并繪制典型工序的專用夾具裝配圖2套
4.繪制夾具主要零件圖若干張
5.編寫設計計算說明書(畢業(yè)論文)一份
四、目標、主要特色及工作進度
1.查閱資料,英文資料翻譯,撰寫開題報告 (2周)3月26日~4月8日
2.繪制萬向節(jié)滑動叉零件圖一份 (0.5周)4月9日~4月11日
3.編制萬向節(jié)滑動叉機械加工工藝規(guī)程一份 (1.5周)4月12日~4月22日
4.設計并繪制典型工序的專用夾具裝配圖1~2套 (3.5周)4月23日~5月16日
5.繪制夾具主要零件圖若干張 (2.5周)5月17日~6月3日
6.編寫設計計算說明書(畢業(yè)論文)一份 (2周)6月4日~6月17日
7.畢業(yè)設計審查、畢業(yè)答辯 (1周)6月18日~ 6月22日
五、參考文獻
[1].王先逵主編,機械制造工藝學,北京,機械工業(yè)出版社,1997.10
[2].孟少農(nóng)主編,機械加工工藝手冊,北京,機械工業(yè)出版社,1991
[3].陳宏鈞,方向明,馬素敏主編,典型零件機械加工生產(chǎn)實例,北京,機械工業(yè)出版
社,2005.1
[4].劉友才,肖繼德主編,機床夾具設計,北京,機械工業(yè)出版社,1991.5
[5].Boyes W E·Jigs and Fixtures·America,SME,1982
畢業(yè)設計(論文)任務書
I、畢業(yè)設計(論文)題目:
萬向節(jié)滑動叉機加工藝及工裝設計
II、畢 業(yè)設計(論文)使用的原始資料(數(shù)據(jù))及設計技術(shù)要求:
設計原始資料:萬向節(jié)滑動叉零件圖一份,零件材料為45鋼。
設計技術(shù)要求:1.中批量生產(chǎn),中型機械加工車間。
2.要求英文資料翻譯忠實原文;
3.要求編制的機械加工工藝規(guī)程合理;
4.要求設計的夾具滿足加工要求;
5.要求圖紙設計規(guī)范,符合制圖標準;
6.要求畢業(yè)論文敘述條理清楚,設計計算正確,論文格式規(guī)范。
III、畢 業(yè)設計(論文)工作內(nèi)容及完成時間:
1.查閱資料,英文資料翻譯(6000字符),撰寫開題報告
(2周)3月24日~4月6日
2.繪制萬向節(jié)滑動叉零件圖一份,設計并繪制零件三維圖形
(2周)4月7日~4月20日
3.編制萬向節(jié)滑動叉機械加工工藝規(guī)程一份 (2周)4月21日~5月4日
4.設計并繪制典型工序的專用夾具裝配圖1~2套 (3周)5月5日~5月25日
5.繪制夾具主要零件圖若干張(以上合計A0圖2張)(1.5周)5月26日~6月4日
6.編寫設計計算說明書(畢業(yè)論文)一份 (1.5周)6月5日~6月15日
7.畢業(yè)設計審查、畢業(yè)答辯 (2周)6月16日~ 6月27日
Ⅳ 、主 要參考資料:
[1].王先逵主編. 機械制造工藝學. 北京:機械工業(yè)出版社,1997.10
[2]. 蘭建設主編. 機械制造工藝與夾具. 北京:機械工業(yè)出版社,2004.7
[3]. 孫麗媛主編. 機械制造工藝及夾具設計指導. 北京:冶金工業(yè)出版社,2007.7
[4].孟少農(nóng)主編. 機械加工工藝手冊. 北京:機械工業(yè)出版社,1991
[5].陳宏鈞等主編. 典型零件機械加工生產(chǎn)實例. 北京:機械工業(yè)出版社,2005.1
[6].劉友才等主編. 機床夾具設計. 北京:機械工業(yè)出版社,1991.5
[7].Boyes W E·Jigs and Fixtures·America,SME,1982
[8]. STRENG.Th. High Quality Fixture Quenching Fixture Types, Levels of
Automation and Machine Types. TRANSACTIONS OF MATERIALS AND HEAT
TREATMENT,2004.5(25)
航空與機械工程 學院 機械設計制造及其自動化 專業(yè)類 050313 班
學生(簽名): 伍峰
日期: 自 2009 年 3 月 24 日至 2009 年 6 月 27 日
指導教師(簽名): 焦益群
助理指導教師(并指出所負責的部分):
機械制造工程 系(室)主任(簽名): 姚坤弟
學士學位論文原創(chuàng)性聲明
本人聲明,所呈交的論文是本人在導師的指導下獨立完成的研究成果。除了文中特別加以標注引用的內(nèi)容外,本論文不包含法律意義上已屬于他人的任何形式的研究成果,也不包含本人已用于其他學位申請的論文或成果。對本文的研究作出重要貢獻的個人和集體,均已在文中以明確方式表明。本人完全意識到本聲明的法律后果由本人承擔。
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NC technology development trends
1 NC system developments at home and abroad
With the rapid development of computer technology, the traditional beginning of a fundamental change manufacturing, the industrial developed countries spent huge sums of money on the modern manufacturing technology research and development, to create a new model. In modern manufacturing systems, CNC technology is the key to technology, which combines microelectronics, computers, information processing, automatic detection, automatic control, such as the integration of advanced, a high-precision, high-efficiency, flexible automation, and other characteristics, the manufacturing industry Flexible automation, integrated, intelligent play the pivotal role. At present, NC technology is undergoing a fundamental change, from a special closed-loop control mode to general-purpose real-time dynamic open all closed-loop control mode. In the integrated on the basis of the CNC systems ultra-thin, ultra-light; on the basis of the intelligent, integrated computers, multimedia, fuzzy control, neural network and other technical disciplines, NC system to achieve high-speed, high-precision, Efficient control, automatic processing can be amended to regulate compensation and the parameters for an online intelligent fault diagnosis and treatment of the network based on the CAD / CAM and CNC systems integration as one machine network, makes the central government centralized control of the group control processing.
For a long time, China's CNC system for traditional closed architecture, but only as a non-intelligent CNC machine controller. Process variables based on experience in the form of pre-fixed parameters, processing procedures before the actual processing by hand or through CAD / CAM and automatic programming system prepared. CAD / CAM and CNC have no feedback control link, the entire manufacturing process CNC is a closed ring-opening implementing agencies. In a complex and changing environment under the conditions of processing tool in the process of composition, workpiece material, spindle speed, feed rate, tool path, cutting depth, step, allowance and other processing parameters, not at the scene circumstances under external interference and real-time dynamic random factors, not by random amendment feedback control link CAD / CAM settings volume, in turn, affect the work of CNC machining efficiency and product quality. Clearly, the traditional fixed CNC system that controlled mode and closed architecture, limiting the CNC to the development of more intelligent control variables, can no longer meet the increasingly complex manufacturing process, therefore, the CNC technology in the potential for change inevitable.
2 NC technology development trends
2.1 Performance development direction
(1) high-speed high-precision efficient speed, accuracy and efficiency of machinery manufacturing technology is the key performance indicators. As a result of the high-speed CPU chips, RISC chip, as well as multi-CPU control system with high-resolution detector of the absolute exchange digital servo system, taken at the same time improve the machine dynamic and static characteristics of effective measures, the high-speed high-precision machine has been efficient greatly enhanced.
(2) Flexible includes two aspects: CNC system itself flexibility, NC system is modular in design, functional coverage, can be cut and strong, and easy to meet the needs of different users; group control system flexibility, with a control system pursuant to the requirements of different production processes, materials flow and information flow automatically dynamically adjusted to maximize their group control system performance.
(3) Process of composite and multi-axis to reduce the process time for the main purpose of supporting the composite processing, and are moving towards multi-axis, multi-function control of the direction of series development. NC Machine Tool Technology composite refers to the workpiece in a single machine on a fixture, through an automatic tool change, rotating spindle head or turntable, and other measures to accomplish multiple processes, multi-surface machining compound. Axis CNC technology, Siemens 880-axis control system for up to 24 axes.
(4) Real-time Intelligent early for the real-time system is usually relatively simple ideal environment, and its role is to scheduling tasks, to ensure that the task be completed within a specified time limit. And artificial intelligence is used to model the realization of mankind's various intelligent behaviors. To the development of science and technology today, real-time systems and artificial intelligence combined with each other towards artificial intelligence is a real-time response, a more realistic field of development, and also in the real-time system with intelligent behavior, the more complex application development, resulting in the Intelligent real-time control of this new area. NC technology in the field, real-time intelligent control of the research and application of development along several main branches: adaptive control, fuzzy control, neural network control, experts control, learning control, feed-forward control. For example, in CNC programming system with expert systems, fault diagnosis expert system parameters automatically set and tool management and automatic compensation, such as adaptive conditioning systems, in high-speed processing of the integrated motion control ahead of the introduction of budget projections and functional, dynamic Feedforward functions in pressure, temperature, position, velocity, control, fuzzy control, the control of the NC system performance greatly improved, so as to achieve optimal control purposes.
2.2 functional development direction
(1) The user interface is graphical user interface with the CNC system of dialogue between the user interface. Since different users interface requirements are different, thus the development of the workload of great user interface, user interface software developed into the most difficult part of. At present INTERNET, virtual reality, visualization in scientific computing and multimedia technologies, such as the user interface has put a higher demand. Graphical user interface greatly facilitates the use of non-professional users, it can be carried out through the window and menu operation, ease of programming and blueprint for rapid programming, three-dimensional dynamic three-dimensional color graphics, graphics, simulation, graphics, dynamic tracking and simulation, and the different directions view and partial display ratio scaling function can be achieved.
(2) visualization in scientific computing visualization in scientific computing can be used for efficient data processing and interpretation of data, so that the exchange of information is no longer limited to using the written word and language, and can direct the use of graphics, image, animation, video and other information. Visualization technology and virtual environment technology, to further broaden the application areas, such as a drawing design, virtual prototyping technology, which shorten product design cycles, improving product quality, reduce production cost is of great significance. NC technology in the areas of visualization technology can be used for CAD / CAM, such as automatic programming design parameters automatically set, tool compensation and tool management of dynamic data processing and display, as well as the processing of visual simulation, and other presentations.
(3) interpolation, and a variety of methods of compensation interpolation methods such as multiple linear interpolation, circular interpolation, cylindrical interpolation, space elliptical surface interpolation, thread interpolation, polar coordinates interpolation, 2 D +2 helical interpolation , NANO interpolation, interpolation NURBS (non-uniform rational B-spline interpolation), spline interpolation (A, B, C kind), such as polynomial interpolation. A variety of functions such as compensation gap compensation vertical compensation quadrant error compensation, and measurement systems pitch error compensation, and speed-related feedforward compensation and temperature compensation, with nearly smooth and exit, as well as the opposite point of the cutter radius compensation.
(4) high-performance PLC contents contents performance CNC system PLC control module can be directly used ladder diagram or high-level language programming, with intuitive online debugging and online help function. Programming tools include the standard used lathe and milling machine PLC user program an example, users may PLC user program standards on the basis of editorial changes, thus easily build their own applications.
(5) application of multimedia technology of multimedia technology-computers, audio-visual and communication technology, and it has the computer integrated voice, text, images and video information. In NC technology, multimedia technology can be applied to information processing integrated, intelligent, real-time monitoring system in the field and production equipment fault diagnosis, monitoring of process parameters such as production has a significant value.
2.3 Development of the Architecture
(1) integration of a highly integrated CPU, programmable RISC chips and large-scale integrated circuits FPGA, EPLD, CPLD and ASIC ASIC chips that can improve the CNC system integration and hardware and software operating speed. Application FPD flat panel display technology can improve display performance. Flat-panel displays with high science and technology content, light weight, small size, low power consumption and portability advantages can be realized Supersized, a counterweight to the emerging and CRT display technology, display technology in the 21st century the mainstream. Application of advanced packaging and interconnect technologies, semiconductors and surface mount technology integration. By increasing the density of integrated circuits, reducing the length and number of interconnection products to reduce prices, improve performance, reduce component size, improve the reliability of the system.
(2) easy to implement modular hardware modular NC systems integration and standardization. According to various functional requirements, the basic modules, such as CPU, memory, position servo, PLC, the input and output interfaces, and communications modules, making the standard Series products, through functional building-block approach to cutting the number of steps and modules, a NC system at different grades.
(3) machine interconnection network for remote control of unmanned operation. Machine through networking, can be in any one machine on the other machine programming, configuration, operation, operating, different machine can be displayed on the screen each machine on the screen.
(4) general-open the closed-loop control mode to adopt a common computer component Bus, modular, open, embedded architecture, ease of cutting, expansion and upgrading, can be composed of different grades, different types, different degree of integration CNC system. Closed-loop control mode is the traditional CNC system only for single closed-open-loop control mode proposed. The manufacturing process is a multi-variable control and the role of integrated processing complex process, including processing, such as size, shape, vibration, noise, temperature and thermal deformation, and other factors, therefore, to achieve the process of multi-objective optimization, Multivariable must adopt the closed-loop control, real-time processing in the dynamic adjustment process variables. Processing the adoption of open universal real-time closed-loop control mode the whole dynamic, easy real-time intelligent computer technology, network technology, multimedia technology, CAD / CAM, servo control, adaptive control, dynamic data management and dynamic tool compensation, dynamic simulation and other high technology into one, a tight closed-loop manufacturing process control system to achieve integrated, intelligent, network-based.
3 PCNC new generation of intelligent CNC system
Research and Development adapted to the current complexity of the manufacturing process, with the structure of the closed-loop control system, a new generation of intelligent PCNC CNC system has become possible. PCNC NC intelligent system will be a new generation of intelligent computer technology, network technology, CAD / CAM, servo control, adaptive control, dynamic data management and dynamic tool compensation, dynamic simulation and other high technology into one, a tight closure of the manufacturing process Central control system.
數(shù)控技術(shù)發(fā)展趨勢
1 國內(nèi)外數(shù)控系統(tǒng)發(fā)展概況
隨著計算機技術(shù)的高速發(fā)展,傳統(tǒng)的制造業(yè)開始了根本性變革,各工業(yè)發(fā)達國家投入巨資,對現(xiàn)代制造技術(shù)進行研究開發(fā),提出了全新的制造模式。在現(xiàn)代制造系統(tǒng)中,數(shù)控技術(shù)是關(guān)鍵技術(shù),它集微電子、計算機、信息處理、自動檢測、自動控制等高新技術(shù)于一體,具有高精度、高效率、柔性自動化等特點,對制造業(yè)實現(xiàn)柔性自動化、集成化、智能化起著舉足輕重的作用。目前,數(shù)控技術(shù)正在發(fā)生根本性變革,由專用型封閉式開環(huán)控制模式向通用型開放式實時動態(tài)全閉環(huán)控制模式發(fā)展。在集成化基礎(chǔ)上,數(shù)控系統(tǒng)實現(xiàn)了超薄型、超小型化;在智能化基礎(chǔ)上,綜合了計算機、多媒體、模糊控制、神經(jīng)網(wǎng)絡等多學科技術(shù),數(shù)控系統(tǒng)實現(xiàn)了高速、高精、高效控制,加工過程中可以自動修正、調(diào)節(jié)與補償各項參數(shù),實現(xiàn)了在線診斷和智能化故障處理;在網(wǎng)絡化基礎(chǔ)上,CAD/CAM與數(shù)控系統(tǒng)集成為一體,機床聯(lián)網(wǎng),實現(xiàn)了中央集中控制的群控加工。
長期以來,我國的數(shù)控系統(tǒng)為傳統(tǒng)的封閉式體系結(jié)構(gòu),CNC只能作為非智能的機床運動控制器。加工過程變量根據(jù)經(jīng)驗以固定參數(shù)形式事先設定,加工程序在實際加工前用手工方式或通過CAD/CAM及自動編程系統(tǒng)進行編制。CAD/CAM和CNC之間沒有反饋控制環(huán)節(jié),整個制造過程中CNC只是一個封閉式的開環(huán)執(zhí)行機構(gòu)。在復雜環(huán)境以及多變條件下,加工過程中的刀具組合、工件材料、主軸轉(zhuǎn)速、進給速率、刀具軌跡、切削深度、步長、加工余量等加工參數(shù),無法在現(xiàn)場環(huán)境下根據(jù)外部干擾和隨機因素實時動態(tài)調(diào)整,更無法通過反饋控制環(huán)節(jié)隨機修正CAD/CAM中的設定量,因而影響CNC的工作效率和產(chǎn)品加工質(zhì)量。由此可見,傳統(tǒng)CNC系統(tǒng)的這種固定程序控制模式和封閉式體系結(jié)構(gòu),限制了CNC向多變量智能化控制發(fā)展,已不適應日益復雜的制造過程,因此,對數(shù)控技術(shù)實行變革勢在必行。
2 數(shù)控技術(shù)發(fā)展趨勢
2.1 性能發(fā)展方向
(1)高速高精高效化 速度、精度和效率是機械制造技術(shù)的關(guān)鍵性能指標。由于采用了高速CPU芯片、RISC芯片、多CPU控制系統(tǒng)以及帶高分辨率絕對式檢測元件的交流數(shù)字伺服系統(tǒng),同時采取了改善機床動態(tài)、靜態(tài)特性等有效措施,機床的高速高精高效化已大大提高。
(2)柔性化 包含兩方面:數(shù)控系統(tǒng)本身的柔性,數(shù)控系統(tǒng)采用模塊化設計,功能覆蓋面大,可裁剪性強,便于滿足不同用戶的需求;群控系統(tǒng)的柔性,同一群控系統(tǒng)能依據(jù)不同生產(chǎn)流程的要求,使物料流和信息流自動進行動態(tài)調(diào)整,從而最大限度地發(fā)揮群控系統(tǒng)的效能。
(3)工藝復合性和多軸化 以減少工序、輔助時間為主要目的的復合加工,正朝著多軸、多系列控制功能方向發(fā)展。數(shù)控機床的工藝復合化是指工件在一臺機床上一次裝夾后,通過自動換刀、旋轉(zhuǎn)主軸頭或轉(zhuǎn)臺等各種措施,完成多工序、多表面的復合加工。數(shù)控技術(shù)軸,西門子880系統(tǒng)控制軸數(shù)可達24軸。
(4)實時智能化 早期的實時系統(tǒng)通常針對相對簡單的理想環(huán)境,其作用是如何調(diào)度任務,以確保任務在規(guī)定期限內(nèi)完成。而人工智能則試圖用計算模型實現(xiàn)人類的各種智能行為??茖W技術(shù)發(fā)展到今天,實時系統(tǒng)和人工智能相互結(jié)合,人工智能正向著具有實時響應的、更現(xiàn)實的領(lǐng)域發(fā)展,而實時系統(tǒng)也朝著具有智能行為的、更加復雜的應用發(fā)展,由此產(chǎn)生了實時智能控制這一新的領(lǐng)域。在數(shù)控技術(shù)領(lǐng)域,實時智能控制的研究和應用正沿著幾個主要分支發(fā)展:自適應控制、模糊控制、神經(jīng)網(wǎng)絡控制、專家控制、學習控制、前饋控制等。例如在數(shù)控系統(tǒng)中配備編程專家系統(tǒng)、故障診斷專家系統(tǒng)、參數(shù)自動設定和刀具自動管理及補償?shù)茸赃m應調(diào)節(jié)系統(tǒng),在高速加工時的綜合運動控制中引入提前預測和預算功能、動態(tài)前饋功能,在壓力、溫度、位置、速度控制等方面采用模糊控制,使數(shù)控系統(tǒng)的控制性能大大提高,從而達到最佳控制的目的。
2.2 功能發(fā)展方向
(1)用戶界面圖形化 用戶界面是數(shù)控系統(tǒng)與使用者之間的對話接口。由于不同用戶對界面的要求不同,因而開發(fā)用戶界面的工作量極大,用戶界面成為計算機軟件研制中最困難的部分之一。當前INTERNET、虛擬現(xiàn)實、科學計算可視化及多媒體等技術(shù)也對用戶界面提出了更高要求。圖形用戶界面極大地方便了非專業(yè)用戶的使用,人們可以通過窗口和菜單進行操作,便于藍圖編程和快速編程、三維彩色立體動態(tài)圖形顯示、圖形模擬、圖形動態(tài)跟蹤和仿真、不同方向的視圖和局部顯示比例縮放功能的實現(xiàn)。
(2)科學計算可視化 科學計算可視化可用于高效處理數(shù)據(jù)和解釋數(shù)據(jù),使信息交流不再局限于用文字和語言表達,而可以直接使用圖形、圖像、動畫等可視信息。可視化技術(shù)與虛擬環(huán)境技術(shù)相結(jié)合,進一步拓寬了應用領(lǐng)域,如無圖紙設計、虛擬樣機技術(shù)等,這對縮短產(chǎn)品設計周期、提高產(chǎn)品質(zhì)量、降低產(chǎn)品成本具有重要意義。在數(shù)控技術(shù)領(lǐng)域,可視化技術(shù)可用于CAD/CAM,如自動編程設計、參數(shù)自動設定、刀具補償和刀具管理數(shù)據(jù)的動態(tài)處理和顯示以及加工過程的可視化仿真演示等。
(3)插補和補償方式多樣化 多種插補方式如直線插補、圓弧插補、圓柱插補、空間橢圓曲面插補、螺紋插補、極坐標插補、2D+2螺旋插補、NANO插補、NURBS插補(非均勻有理B樣條插補)、樣條插補(A、B、C樣條)、多項式插補等。多種補償功能如間隙補償、垂直度補償、象限誤差補償、螺距和測量系統(tǒng)誤差補償、與速度相關(guān)的前饋補償、溫度補償、帶平滑接近和退出以及相反點計算的刀具半徑補償?shù)取?
(4)內(nèi)裝高性能PLC 數(shù)控系統(tǒng)內(nèi)裝高性能PLC控制模塊,可直接用梯形圖或高級語言編程,具有直觀的在線調(diào)試和在線幫助功能。編程工具中包含用于車床銑床的標準PLC用戶程序?qū)嵗脩艨稍跇藴蔖LC用戶程序基礎(chǔ)上進行編輯修改,從而方便地建立自己的應用程序。
(5)多媒體技術(shù)應用 多媒體技術(shù)集計算機、聲像和通信技術(shù)于一體,使計算機具有綜合處理聲音、文字、圖像和視頻信息的能力。在數(shù)控技術(shù)領(lǐng)域,應用多媒體技術(shù)可以做到信息處理綜合化、智能化,在實時監(jiān)控系統(tǒng)和生產(chǎn)現(xiàn)場設備的故障診斷、生產(chǎn)過程參數(shù)監(jiān)測等方面有著重大的應用價值。
2.3 體系結(jié)構(gòu)的發(fā)展
(1)集成化 采用高度集成化CPU、RISC芯片和大規(guī)??删幊碳呻娐稦PGA、EPLD、CPLD以及專用集成電路ASIC芯片,可提高數(shù)控系統(tǒng)的集成度和軟硬件運行速度。應用FPD平板顯示技術(shù),可提高顯示器性能。平板顯示器具有科技含量高、重量輕、體積小、功耗低、便于攜帶等優(yōu)點,可實現(xiàn)超大尺寸顯示,成為和CRT抗衡的新興顯示技術(shù),是21世紀顯示技術(shù)的主流。應用先進封裝和互連技術(shù),將半導體和表面安裝技術(shù)融為一體。通過提高集成電路密度、減少互連長度和數(shù)量來降低產(chǎn)品價格,改進性能,減小組件尺寸,提高系統(tǒng)的可靠性。
(2)模塊化 硬件模塊化易于實現(xiàn)數(shù)控系統(tǒng)的集成化和標準化。根據(jù)不同的功能需求,將基本模塊,如CPU、存儲器、位置伺服、PLC、輸入輸出接口、通訊等模塊,作成標準的系列化產(chǎn)品,通過積木方式進行功能裁剪和模塊數(shù)量的增減,構(gòu)成不同檔次的數(shù)控系統(tǒng)。
(3)網(wǎng)絡化 機床聯(lián)網(wǎng)可進行遠程控制和無人化操作。通過機床聯(lián)網(wǎng),可在任何一臺機床上對其它機床進行編程、設定、操作、運行,不同機床的畫面可同時顯示在每一臺機床的屏幕上。
(4)通用型開放式閉環(huán)控制模式 采用通用計算機組成總線式、模塊化、開放式、嵌入式體系結(jié)構(gòu),便于裁剪、擴展和升級,可組成不同檔次、不同類型、不同集成程度的數(shù)控系統(tǒng)。閉環(huán)控制模式是針對傳統(tǒng)的數(shù)控系統(tǒng)僅有的專用型單機封閉式開環(huán)控制模式提出的。由于制造過程是一個具有多變量控制和加工工藝綜合作用的復雜過程,包含諸如加工尺寸、形狀、振動、噪聲、溫度和熱變形等各種變化因素,因此,要實現(xiàn)加工過程的多目標優(yōu)化,必須采用多變量的閉環(huán)控制,在實時加工過程中動態(tài)調(diào)整加工過程變量。加工過程中采用開放式通用型實時動態(tài)全閉環(huán)控制模式,易于將計算機實時智能技術(shù)、網(wǎng)絡技術(shù)、多媒體技術(shù)、CAD/CAM、伺服控制、自適應控制、動態(tài)數(shù)據(jù)管理及動態(tài)刀具補償、動態(tài)仿真等高新技術(shù)融于一體,構(gòu)成嚴密的制造過程閉環(huán)控制體系,從而實現(xiàn)集成化、智能化、網(wǎng)絡化。
3 智能化新一代PCNC數(shù)控系統(tǒng)
當前開發(fā)研究適應于復雜制造過程的、具有閉環(huán)控制體系結(jié)構(gòu)的、智能化新一代PCNC數(shù)控系統(tǒng)已成為可能。智能化新一代PCNC數(shù)控系統(tǒng)將計算機智能技術(shù)、網(wǎng)絡技術(shù)、CAD/CAM、伺服控制、自適應控制、動態(tài)數(shù)據(jù)管理及動態(tài)刀具補償、動態(tài)仿真等高新技術(shù)融于一體,形成嚴密的制造過程閉環(huán)控制體系。