數(shù)控系統(tǒng)輔助液壓挖掘機(jī)的概念課程畢業(yè)設(shè)計外文文獻(xiàn)翻譯@中英文翻譯@外文翻譯

1、<p><b>　　Abstract</b></p><p>　　A concept of digital control system to assist the operators of hydraulic excavators is presented and discussed. Then, control system based on described ideas w

2、as mounted on a special numerically controlled stand, equipped with D r A and A r D converters, where small hydraulic backhoe excavator K-111 fixtures were used. Experimental results shows that it fulfils all described r

3、equirements and can be used as the machine operator assist. It enables for precision tool guidance. automatic repetition </p><p>　　Keywords: Digital control system; Hydraulic excavators; Tool trajectories<

4、;/p><p>　　1. Introduction</p><p>　　The automation of heavy machines, including hydraulic excavators, began in mid-1970s and was</p><p>　　possible due to invention of real time controll

5、ers and hydraulic elements with good dynamic properties. The first excavator equipped with several mechatronics systems, which was shown as a working model, was the excavator FUTURE prepared by Orenstein and Koppel for B

6、AUMA’83 Fairs. Since that time, machines equipped with systems automating the engine operation, pumps operation, machine fixtures, machine diagnostic, etc.,</p><p>　　are presented and offered. Such systems b

7、ring real help to the operator and clear economical profit. For example, LIEBHERRR902 excavator equipped with LITRONIC System. has for a trench digging the efficiency 40% higher and unit costs 30% lower, than similar mac

8、hine without such automatic system. Although automation? . in some case, optimization of several machine systems develops quite fast, the main machine process—the shoving process—has no proper understanding and descripti

9、on until now. Its a</p><p>　　tool during the previous stage of the shoving process. To realize such trajectories for practical purpose and real machines, it is necessary to build a special control system for

10、 the tool motion, which enables automatic realization of such trajectories as well as realization of other tasks that help the operator.</p><p>　　2. The basic concept of the computer aided control systemIt&l

11、t;/p><p>　　It was shown before that analyzing the the soil deformation during the shoving process, it is possible to determine energetically optimal cutting tool trajectories. Hence, the automatic tool movemen

12、t along slip lines generated in cohesive material has to be a quite important option of proposed system. It should also enable precision tool guidance, automatic repetition of already realized movements</p><p&

13、gt;　　? . for example, ‘teach-in’ , realization of some tool movements impossible to realize manually, etc. Taking into account to-day experience with automation of heavy machines, such system should be constructed to ass

14、ist machine operator, who still plays a main decisive and control role. Hence, the proper separation of tasks, between the control sys-tem and the operator, is necessary. Such control system for excavators was built on l

15、aboratory scale. Its basic assumptions can be stat d w x ? . as f</p><p>　　hydraulic valves of the fixture cylinders is controlled through the computer. The direct operator control is? . possible only in cas

16、e of emergency conditions. 3The feedback between the machine environment and control system is realized through the operator. He participates continuously in the process of the con-? . control of machine fixtures motion.

17、 4 For realization of the tool motions which are impossible for manual control, the operator has a possibility to coordinate displacement of separat</p><p>　　Presented concept is based on such cooperation be

18、tween the operator and control system that the fixture movements are controlled by the operator while the control system corrects him or, when ordered, can act automatically</p><p>　　3. Examples of the contr

19、ol system functioning</p><p>　　The control system based on described above ideas was mounted on a special numerically con-trolled stand, equipped with PC computer having CrA and ArC converters, where small h

20、ydraulicw x backhoe excavator K-111 fixtures were used 14–17 .The control system of the fixture motions utilizes the control system of the cylinder positions. The fixture cylinder displacement is controlled by the propor

21、tional hydraulic valves fed by the variable out putmultipiston pump. The control system for fixture cyli</p><p>　　3.1. The tool moÕement along prescribed line</p><p>　　The control system bu

22、ild for experimental standw x 15–17 enables, among others, programming the work motion in the excavator work space, or in its configuration space, using ‘point to point’ technique. In this method, the coordinates of the

23、initial and final points, and sufficient number of the character isticnodal points, are defined. Values describing this points are then introduced to the system, where remaining points of the trajectory are calculated us

24、ing interpolation methods. Linear or th</p><p>　　3.2. The tool moÕement using the setting model</p><p>　　along straight lines In presented case, the coordination of the fixture cylinder mov

25、ement was realized by hardware, that means using the setting model. It can also be realized? by software. The machine operator using special. buttons , can generate horizontal or vertical tool movement preserving the con

26、stant value of the tool cutting angle in every point of the machine working space. The prescribed tool path is stored using the point method in the configuration space. Further-more, the machine o</p><p>　　3

27、.3. Automatic tool moÕement along a slip line</p><p>　　Analysis of experimental results of the soil shoving process shows that it is possible to predict theoretically the slip lines positions and energy

28、 etically optimal tool trajectories. It can be done for homogeneous material under laboratory conditions. In real situations, when material is not homogeneous and not well-defined, the material sleep lines has to be dete

29、cted automatically. The procedure of automatic slip line detection is based on the observation that when cutting tool begins to penet</p><p>　　used for slip line detection. Such procedure, which simplified v

30、ersion is described below, can be realized as follows. Cutting tool motion is realized as a sum of horizontal, vertical and rotational movements and horizontal reaction of the soil is measured and followed. Firstly, the

31、tool moves horizontally up to the moment when the horizontal force drops, that coincides with creation of slip lines system originating from the tool? . end Fig. 1 . If such slip lines cannot be created as a</p>&

32、lt;p>　　? result of horizontal pushing, a special procedure for. example tool rotation can be applied. Then, tool is moved vertically by prescribed displacement value? and then moves again horizontally rotation of the.

33、 tool can be added up to the moment when horizontal force begins to increase. If so, , and then horizontally, and so on. This way, the tip of the tool automatically? follows in a step way the slip line. Results of such p

34、reliminary tests are presented in Figs. 11 and 12. As a simplified mod</p><p>　　4. Conclusions</p><p>　　Experimental results show that presented control system fulfils all described requirements

35、 and can be used as the machine operator assist. It enables for precision tool guidance, automatic repetition of realized movements, realization of specific tool trajectories including energetically optimal paths and aut

36、omatic improvement or optimization of realized paths. Tool trajectories can also be prescribed using the setting model, making excavator the machine of tele operator class. Presented system </p><p>　　Acknowl

37、edgements This research was sponsored by the Project KBN7T07C00412 ‘Optimization of the soil shoving process due to heavy machines of an excavator type’ realized at Kielce University of Technology.</p><p>　　

38、數(shù)控系統(tǒng)輔助液壓挖掘機(jī)的概念</p><p><b>　　摘要</b></p><p>　　數(shù)控系統(tǒng)輔助液壓挖掘機(jī)操作者的概念被提出和討論。然后，基于描述概念性的控制系統(tǒng)被安裝在專門的數(shù)控平臺上，平臺上配備D/A和A/D轉(zhuǎn)換器，已經(jīng)在小型液壓拉鏟挖掘機(jī)K-111的工裝上應(yīng)用。實(shí)驗(yàn)結(jié)果表明它能滿足所有描述的需求，并且能用于輔助機(jī)器操作員工作。它能為精密工具做引導(dǎo)，了解的

39、運(yùn)動的自動重復(fù)和特定工具軌道 (包括最佳的路徑)，還有自動改進(jìn)或優(yōu)化路徑。工具軌道也能被規(guī)定使用設(shè)定模型，使挖掘機(jī)成為遙控操縱類別的機(jī)器?，F(xiàn)行的系統(tǒng)能基本用于真機(jī)控制系統(tǒng)。1998 Elsevier 科學(xué) B.V. 版權(quán)所有。</p><p>　　關(guān)鍵詞：數(shù)控系統(tǒng)；液壓挖掘機(jī)；工具軌道</p><p><b>　　1 介紹</b></p><p&

40、gt;　　重型機(jī)械的自動化，包括液壓挖掘機(jī)在內(nèi)，始于20世紀(jì)七十年代中期并成為可能。這主要由于時實(shí)控制系統(tǒng)和高動力性能的液壓元件的發(fā)明。第一臺配備若干機(jī)械電子系統(tǒng)的挖掘機(jī)被當(dāng)作模型展示，這是Orenstein 和 Koppel為BAUMA'83 展覽會準(zhǔn)備的未來的液壓挖掘機(jī)。自從那次以后，許多配備了自動控制系統(tǒng)的器被展現(xiàn)和要求 如引擎操作，泵操作，機(jī)器工裝，機(jī)器診斷等等。這種系統(tǒng)帶來了真正的幫助和明顯的利潤。舉例來說, 被裝備

41、LITRONIC 系統(tǒng)的 LIEBHERR R902挖掘機(jī)（對于挖溝機(jī)），對比沒有配備這種自動控制系統(tǒng)的相同機(jī)型來說，效率提高達(dá)40％成本降低30％。雖然一些機(jī)器的自動系統(tǒng)（在一些情況下的優(yōu)化）發(fā)展的相當(dāng)快，但是直到現(xiàn)在主要的機(jī)器程序－推處理-沒有適當(dāng)?shù)睦斫夂兔枋觥Ｋ淖詣踊喈?dāng)?shù)挠邢蓿ㄈ缰貜?fù)運(yùn)動和激光平行系統(tǒng)等等），并且優(yōu)化處理系統(tǒng)還沒有發(fā)展。比較新的實(shí)驗(yàn)結(jié)果清晰地表明，優(yōu)化的工裝軌跡在連續(xù)材料情況下，工具的尖端不得不沿著前一個推擠過

42、程形成的滑道運(yùn)動。實(shí)際上了解這樣的軌跡和真機(jī)，為工具的運(yùn)動建立了一個特別的控制系統(tǒng)是必要的，這使得實(shí)現(xiàn)這樣的軌跡像實(shí)現(xiàn)其它幫助操作員實(shí)現(xiàn)其</p><p>　　2 計算機(jī)輔助控制系統(tǒng)的基本</p><p>　　據(jù)之前顯示，在推土過程中分析土體變形的力學(xué)機(jī)理，可能決定刀具軌跡的優(yōu)化。然而，在連續(xù)的材料中產(chǎn)生了工具沿著滑線的自動移動，這必須成為被提倡的系統(tǒng)的一個重要選項(xiàng)。這也應(yīng)該成為精密工具的

43、向?qū)?，自動重?fù)已經(jīng)確認(rèn)的運(yùn)動（例如“討論會”），實(shí)現(xiàn)一些手工不能實(shí)現(xiàn)的工具動作等等。</p><p>　　考慮到對重型機(jī)器自動化的經(jīng)驗(yàn)少，這樣的系統(tǒng)應(yīng)該被裝配在機(jī)器上來協(xié)助操作員，并且扮演決定性和控制性的角色。因此，在控制系統(tǒng)和操作員之間的適當(dāng)?shù)姆蛛x是必要的。</p><p>　　這種用于挖掘機(jī)上的控制系統(tǒng)是建立在實(shí)驗(yàn)室范圍上的，其基本假設(shè)可以闡述如下[13]，（1）控制中心的操作系統(tǒng)是基

44、于兩個數(shù)字系統(tǒng)的協(xié)作下的。第一個通過控制液壓缸的位置來控制機(jī)械夾具的運(yùn)動。第二個為第一個系統(tǒng)產(chǎn)生控制信號。（2）在標(biāo)準(zhǔn)工況下，夾具液壓缸的比例液壓閥通過計算機(jī)來控制。直接的操作員控制僅在出現(xiàn)緊急情況下才能用。（3）機(jī)器環(huán)境和控制系統(tǒng)之間的反饋是通過操作員來實(shí)現(xiàn)的。他連續(xù)的參加機(jī)器夾具運(yùn)動控制的過程中。（4）為了了解這種人工控制不能實(shí)現(xiàn)的工具運(yùn)動，操作員有可能通過硬件或軟件來調(diào)整單個液壓缸的位移。（5）操作員有可能轉(zhuǎn)換夾具運(yùn)動的自動控制來

45、認(rèn)識特殊的工具軌跡。在這里，工具的尖端沿著滑線或特定的已經(jīng)確認(rèn)的或是事先存在的軌跡移動。（6）優(yōu)化的工具軌跡也可以被認(rèn)為是操作員給定的軌跡的修正。（7）系統(tǒng)可以在考慮某些限制的基礎(chǔ)上來修正操作員說給定的軌跡，如：幾何關(guān)系限制，泵的最大能力限制，泵的最大輸出限制和泵的最大功率限制等等。</p><p>　　現(xiàn)行的概念是基于操作員和控制系統(tǒng)之間的協(xié)作，這就是說夾具的移動是在控制系統(tǒng)修正下的操作員的控制或是在操作員的命

46、下控制系統(tǒng)的自動化控制。</p><p>　　3 控制系統(tǒng)功能實(shí)例</p><p>　　控制系統(tǒng)基于上述理念被安裝在一個特殊的數(shù)控場合，配備有PC和C/A、A/C轉(zhuǎn)換器。在小型液壓挖掘機(jī)K-111的設(shè)備中有所應(yīng)用[14-17]。夾具利用液壓缸的位置控制系統(tǒng)來實(shí)現(xiàn)夾具的位移控制。夾具液壓缸位移是靠變量柱塞泵反饋的成比例液壓值來控制的。夾具液壓缸控制系統(tǒng)基于三個液壓控制系統(tǒng)，每個控制系統(tǒng)應(yīng)用

47、PID或是狀態(tài)控制器，控制不同的液壓缸的位移[14]。</p><p>　　它可以用 工具軌跡計劃編制，測量作用力和位移，以及其它于夾具位移有關(guān)的量來控制夾具的位移。實(shí)驗(yàn)的數(shù)據(jù)的獲得也是可行的。</p><p>　　當(dāng)建立控制系統(tǒng)時，應(yīng)該考慮的相當(dāng)重要的問題之一是工具軌跡計劃編制的方法。這種方法（通常）從兩步來認(rèn)識[15],在第一步中，計劃和決定軌跡的形狀。在第二步中，軌跡曲線已決定性的方

48、法按時間進(jìn)行參數(shù)化，這種決定性的方法把軌跡定義在廣義坐標(biāo)內(nèi)。在此基礎(chǔ)上，推廣到廣義坐標(biāo)的時間描述機(jī)器構(gòu)造空間被決定。挖掘機(jī)在這種情況下，液壓缸的長度都是相匹配的。然后，它們作為控制系統(tǒng)信號被用于重復(fù)計劃好的軌跡。有些系統(tǒng)能力描述如下。</p><p>　　3.1 工具沿著指定好的路線移動</p><p>　　為實(shí)驗(yàn)平臺建立的控制系統(tǒng)，在挖掘機(jī)工作空間或是在其構(gòu)造空間內(nèi)運(yùn)動應(yīng)用“點(diǎn)對點(diǎn)”技術(shù)

49、用這種方法，坐標(biāo)的最初和最終的點(diǎn)以及足夠數(shù)量的特有的節(jié)點(diǎn)被定義。然后描述這個點(diǎn)的值被導(dǎo)入系統(tǒng)，而其余各點(diǎn)的軌跡的計算采用內(nèi)差值法。線性的或是三次多項(xiàng)式差值法被應(yīng)用。軌跡的時間參數(shù)化才能通過確定的軌跡運(yùn)行時間，以及其劃分個別路徑環(huán)節(jié)而被認(rèn)識?？紤]到系統(tǒng)計算液壓缸的速度的一些限制，測定兩個相鄰點(diǎn)之間的運(yùn)行時間（或者在最優(yōu)化的情況下）。</p><p>　　在這樣的標(biāo)準(zhǔn)挖掘施工情況下，很難精確實(shí)現(xiàn)軌跡，在這里同時移動兩

50、三個液壓缸是必要的。</p><p>　　3.2 沿著直線的工具移動</p><p>　　在當(dāng)前的情況下，裝置的液壓缸的同時移動通過硬件實(shí)現(xiàn)，這意思就是通過建模實(shí)現(xiàn)。它也可以通過軟件來實(shí)現(xiàn)，這意思是通過機(jī)器操作者實(shí)現(xiàn)（用專門的按鈕）。機(jī)器在任意工作空間內(nèi)，工具水平或垂直切削角度保持為常數(shù)。在構(gòu)造空間內(nèi)，以點(diǎn)的方法描述工具路徑。此外，機(jī)器操作者可以決定移動速度。速度靠控制系統(tǒng)考慮輸出反饋的情

51、況下保證正確。水平運(yùn)動的控制結(jié)果在圖7和圖8中表示出來。切削工具的軌跡在圖7中表示出來。他們假設(shè)反饋的計算長度以點(diǎn)線表示出來。工具軌跡的時間參數(shù)化方法于建模相似，看起來操作者給的速度太高，并且系統(tǒng)修正的液壓缸移動適時的與假設(shè)輸出反饋相保持。工具沿著斜線移動的例子在圖9和圖10中展示出來。在圖中工具軌跡和相應(yīng)液壓缸被畫出來，這樣的移動以水平和垂直運(yùn)動之和來實(shí)現(xiàn)（斜線以水平和垂直速度來合成）。例如，沿著斜線的軌跡可以在推擠過程的退回階段沿著

52、滑線或自動形成，使得土壤陡坎。</p><p>　　3. 3沿著滑線的工具的自動移動</p><p>　　實(shí)驗(yàn)結(jié)果分析的土壤搡過程顯示，預(yù)計理論滑線的位置合周期的優(yōu)化工具軌跡是可能的。可以在驗(yàn)室情況下的均勻材料中實(shí)現(xiàn)。在現(xiàn)實(shí)情況下，當(dāng)材料不是均勻的或是不好定義的時，材料的滑線必須自動的被探測?；€探測的自動化過程是基于觀察的，當(dāng)工具開始穿透稠密的材料時，作用在工具上的水平力的增加時可以觀察

53、的。這種情況也發(fā)生在當(dāng)工具尖端從沿著滑線（這里的物質(zhì)密度相當(dāng)?。┫驔]有動過的材料（滑線上下沒有改變的材料）移動時。然而，推力增加的觀察能被用于滑線的探測。這個過程在下面簡要介紹和實(shí)現(xiàn)。</p><p>　　切削工具的移動時水平、垂直合旋轉(zhuǎn)運(yùn)動的合成，并且的水平反作用力被測量和跟蹤。首先，當(dāng)水平力下降時，工具水平向前移動，同時伴隨滑線系統(tǒng)從末端產(chǎn)生，一個特別的過程（以旋轉(zhuǎn)工具為例）被實(shí)現(xiàn)。然后，當(dāng)水平力增加并且超過

54、定義值時。工具按照指定的位移值垂直運(yùn)動，并且再進(jìn)行水平移動（工具的旋轉(zhuǎn)被增加）。如果這樣，工具再一次垂直運(yùn)動（按照所描述的位移），并且然后水平運(yùn)動等等，這樣工具的尖端自動沿著滑線移動（以步進(jìn)方式）。</p><p>　　初步測試的結(jié)果在圖11和圖12中展示出來。作為一個簡化的模型，工具沿著土壤陡坡傾斜0.61rad的可能被調(diào)查。為了定義水平力的最大值和定義垂直位移，控制系統(tǒng)自動沿著陡坡跟隨工具。橫向力于橫向位移和

55、工具軌跡進(jìn)行滑線偵察在圖11中展示。圖11的部分放大在圖12中展示，圖12展示了控制系統(tǒng)的作用。</p><p><b>　　4總結(jié)</b></p><p>　　實(shí)驗(yàn)結(jié)果表明,提出的控制系統(tǒng)能夠滿足上述所有要求的描述,可以用來作為機(jī)床操作協(xié)助。自動重復(fù)實(shí)現(xiàn)運(yùn)動，專用工具（包括高度優(yōu)化路徑）軌跡的實(shí)現(xiàn)和自動改進(jìn)或?qū)崿F(xiàn)路徑的優(yōu)化。工具軌跡也可以用建模來規(guī)定，使挖掘機(jī)成為遙