【正文】 i. As an indicator for insufficient hydraulic flow, a function of the position errors of the cylinders is chosen. The vector s j contains the setpoint positions for the cylinders in each leg and i j the vector of measured positions. The difference is the error in meters. Where fl stands for front left, hr for hind right and so forth. With the weight matrix W, the influence of the four cylinders in each leg on the foot position can be adjusted. We take the normalized weighed sum of the squares of the errors for all cylinders e and its first time derivation de and normalize both with the admissible errors (thresholds e thr and de thr). If the sum of e and de exceeds the upper limit, the model time is slowed down. As both e and de are normalized with a threshold, this upper limit can be . . fixed. In this case it is 2. The third threshold (lower limit) is used to decide when to increase the speed again. To prevent a decrease in error triggering a stop in deceleration or even an acceleration, even if the error is still too large, de is only added if it is positive. where ?k mt,dec is the rate of change of k mt for deceleration and ?k mt,acc is the same for acceleration. K mt has to stay inside the limit [k mt,min? 1]. Results Values for thresholds, acceleration and decelerationrates of model time and cylinder weights are set empirically. The cylinders at the hip joint have a higher influence on the foot position than cylinder no. 4 at the knee. The corresponding weighing is set to 2:1. As the system has to react very quickly to errors,the deceleration rate ?k mt,dec is high. To prevent too much oscillation, the acceleration rate ?k mt,acc is set lower than ?k mt,dec.] . . Fig. 7: Cylinder positions for spe。e 1, 47057 Duisburg, Germany Email: fgermann, mueller, ABSTRACT When operating walking machines, only a coordinated movement of all cylinders and/or motors can lead to safe, stable walking. The large hydraulically driven walking machine . . ALDURO, which is investigated in this paper, has no external power supply, and therefore the size of the onboard hydraulic power pack and its diesel engine is limited by its weight. When moving several cylinders with high speed, the hydraulic supply can bee insufficient and the resulting trajectories of feet and platform can bee unpredictable. When the ALDURO is near its stability limit such behaviour can lead to instability and toppling of the system. The proposed solution under discussion here is to observe the position errors and time derivatives for the cylinders and based on this reduce the speed when necessary. 1. INTRODUCTION The system investigated in this paper is the Anthropomorphically Legged and Wheeled Duisburg Robot (ALDURO). It consists of a platform of by with a cabin for the operator and four legs, each long. The estimated weight is 1200 kg. It can be used as a quadruped walking machine (Fig. 2), and by replacing the two hind feet with wheels, it can also be used as a bined legged and wheeled vehicle (Fig. 1). The latter bines the advantages of a walking machine high mobility with the stability and speed of wheeled vehicles [2]. When operating in steep and dangerous terrain, safety plays an important role. It must be guaranteed that the cylinders follow the calc ulated trajectories exactly since a wrong movement might cause the robot to bee instable. ALDURO39。uller and Manfred Hiller GerhardMercatorUniversit196。 by University of Technology, Sydney SPEEDADAPTED TRAJECTORIES IN THE CASE OF INSUFFICIENT YDRAULIC RESSURE FOR THE FOURLEGGED LARGESCALE WALKING VEHICLE ALDURO Daniel Germann, J196。 真心地感謝陳為國教授給予作者論文工作的熱情幫助和提供寶貴的建 議！ 梅欣、張靜等同學(xué)在畢業(yè)設(shè)計期間為作者提供了大力的幫助，協(xié)助收集了相關(guān)資料，作者在此表示深深的謝意！ 真心地感謝 Vanilla 小姐在大學(xué)階段的學(xué)習(xí)生活中給予的支持和關(guān)心以及在論文寫作的過程中提出的建議！ 最后，作者誠心感謝所有關(guān)心和支持本論文的人們。 首先，真心地感謝導(dǎo)師李堯忠的精心指導(dǎo)。在這忙碌的三個月中，通過對各種相關(guān)資料的查閱，更加牢固地掌握了所學(xué)的專業(yè)知識，更多的了解了當(dāng)今科學(xué)前沿的發(fā)展情況，大大地拓寬了知識面。 4．液壓缸的結(jié)構(gòu)設(shè)計參考了其他油缸的設(shè)計思路，并在此基礎(chǔ)上做了很多改進(jìn)。 . . 3．選擇了以集成塊作為聯(lián)接方式來進(jìn)行系統(tǒng)的裝配。 2．油箱及各主要附件的 選擇均以系統(tǒng)的要求為標(biāo)準(zhǔn)。現(xiàn)將有關(guān)總結(jié)如下： 1．液壓系統(tǒng)的設(shè)計計算。 圖 49 外螺紋法蘭式安裝方式 結(jié) 論 本文對具有典型代表性的液壓系統(tǒng) —— 25KN 單柱液壓機液壓系統(tǒng)進(jìn)行了參數(shù)計算和結(jié)構(gòu)設(shè)計。 端部結(jié)構(gòu) 活塞桿端部結(jié)構(gòu)見表 45： 表 45 活塞桿端部結(jié)構(gòu) 結(jié)構(gòu)形式 外螺紋 內(nèi)螺紋 單耳環(huán) 結(jié)構(gòu)簡圖 圖 46 排氣閥 液壓缸安裝聯(lián)接部分的型式 液壓缸進(jìn)出油口的聯(lián)接 液壓缸進(jìn)出油口接頭采用螺紋聯(lián)接（見圖 47及圖 48）。上述兩種聯(lián)軸器中，簡單型彈性圈柱銷聯(lián)軸器的結(jié)構(gòu)簡單，裝卸方便，使用壽命較長，幫比彈性圈柱銷聯(lián)軸器用得多些。各類液壓泵的吸油高度見表 32： 表 32 各類油泵吸油高度 油泵類型 齒輪泵 葉片泵 柱塞泵 螺桿泵 吸油高度（ mm） 300~400 不大于 500 不大于 500 500~1000 . . 液壓泵與電機的聯(lián)接 液壓泵與電機之 間的聯(lián)軸器，一般用簡單型彈性圈柱銷聯(lián)軸器或彈性圈柱銷聯(lián)軸器，其二者的共同特點是傳遞扭矩范圍較大，轉(zhuǎn)速較高，彈性好，能緩沖扭矩急劇變化引起的振動，能補償軸位移。 ⑷ 液壓泵吸油管路的安裝必須注意密封可靠及油管插入油液有足夠的深度，以防止空氣被吸入液壓泵。 ⑵ 調(diào)整好液壓泵與電機的聯(lián)軸器，使二者同心，用手撥動聯(lián)軸器時不能有松緊不一致的現(xiàn)象。上置式指液壓泵裝置安裝在油箱上，立式安裝的液壓泵皆為上置式。齒輪泵與柱塞泵一般為臥式安裝。 液壓泵的安裝方式 金屬切削機床的液壓站，多用定量或限壓式變量葉片泵。具體而言，主要指電機、聯(lián)軸器、液壓泵、吸油管、排油管以及吸油管口的濾油器。泵的兩個吸油區(qū)和兩個壓油區(qū)是徑向?qū)ΨQ的，作用在轉(zhuǎn)子上的液壓力徑向平衡，所以又稱為平衡式葉片泵。在轉(zhuǎn)子順時針方向旋轉(zhuǎn)的情況下，密封工作腔的容積在左上角和右下角處逐漸增大，為吸油區(qū)；在左下角和右上角處逐漸減小，為壓油區(qū)；吸油區(qū)和壓油區(qū)之間有一段封油區(qū)把它們隔開。定子的內(nèi)表雙作用葉片泵 的工作原理：面是由兩段長半徑圓弧、兩段短半徑圓弧和四段過渡曲線八個組成，且定子和轉(zhuǎn)子是同心的。安裝大小不同的單泵，可以得到兩種大小不同的流量，以適應(yīng)液壓系統(tǒng)各種不同速度的要求。由系統(tǒng)圖可見，從泵到液壓缸之間串接有一個單向調(diào)節(jié)器速閥和一個電磁換向閥，取 ??? = 液壓泵工作壓力為： PP = + = 5 MPa (2) 液壓泵流量的確定 ? ?max ??? ? （ 32） 由工況圖看出，系統(tǒng)最大流量發(fā)生在快退工況， 410215 ??? .Q m a x? m3/s，泄漏系數(shù) K = , 求得液壓泵流量 : 410316 ??? .Q? m2/s ( L/mm) 選用 YB140 型雙聯(lián)葉片泵。液壓泵的額定流量是指在正常工作條件下，按試驗標(biāo)準(zhǔn)規(guī)定必須保證的流量，亦即在額定轉(zhuǎn)速和額定壓力下由泵輸出的流量。 液壓泵的工作壓力是指泵實際工作時的壓力。 上重型液壓站 上海重型機器廠液壓站油箱容量 1200L 與 2200L 兩種， 1200L 的工作壓力為 MPa， 2200L 的為 5 MPa，流量均為 320L/min。 YH 型液壓站 YH 型液壓站油箱容量 120~2021L，壓力為 14 MPa，流量在 10~250L/min 范圍，由沈陽重型機器廠生產(chǎn)。 CJZ型液壓站 CJZ 型液壓泵站油箱容量有 100L 與 160L 兩種，壓力為 5MPa，流量為 20~63L/min范圍。常州液壓件廠生產(chǎn)。上海液壓件一廠生產(chǎn)。 YZ系列液壓泵站生產(chǎn)廠有：上海高行液壓件廠、長沙液壓件廠、南京液壓件三廠等。選用各種不同的泵，得到各種不同流量、壓力的規(guī)格。 液壓泵站油箱公稱容量系列（ GB 2876— 81） 表 31 油箱容量 GB 287681 L 4 10 25 40 63 100 160 250 315 400 500 630 800 1000 1250 . .