基于慧魚組件的多功能物料運輸車機器人設(shè)計起升機構(gòu)結(jié)構(gòu)部分設(shè)計【履帶式災(zāi)害救援機器人設(shè)計】
基于慧魚組件的多功能物料運輸車機器人設(shè)計起升機構(gòu)結(jié)構(gòu)部分設(shè)計【履帶式災(zāi)害救援機器人設(shè)計】,履帶式災(zāi)害救援機器人設(shè)計,基于慧魚組件的多功能物料運輸車機器人設(shè)計起升機構(gòu)結(jié)構(gòu)部分設(shè)計【履帶式災(zāi)害救援機器人設(shè)計】,基于,組件,多功能,物料,運輸車,機器人,設(shè)計,機構(gòu),結(jié)構(gòu),部分,部份,履帶式,災(zāi)害
南京理工大學泰州科技學院
畢業(yè)設(shè)計(論文)外文資料翻譯
學院 (系)： 機械工程學院
專 業(yè)： 機械工程及自動化
姓 名： 汪俊
學 號： 0601610108
外文出處： Journal of Mechanical Design
附 件： 1.外文資料翻譯譯文；2.外文原文。
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附件1：外文資料翻譯譯文
ResQuake：遠程操作救援機器人
ResQuake作為一種遠程操作救援機器人，它的設(shè)計程序以及對其動態(tài)分析，生產(chǎn)過程，控制系統(tǒng)，防滑性能改進等一直被人們所探討。人們首先要探討的問題是規(guī)定機器人要完成的總?cè)蝿?wù)以及組成機器人基本結(jié)構(gòu)的各種機構(gòu)。選擇適當?shù)臋C構(gòu)、幾何尺寸、對質(zhì)量進行定性分析以形成系統(tǒng)的運動學和動力學模型。其次是對每個構(gòu)建的強度進行分析以最終定型并提出機構(gòu)模型。接著對控制系統(tǒng)進行簡要的介紹，該控制系統(tǒng)包括用作主處理器的操作者的電腦以及安裝在機器人身上作為從處理器的便攜式電腦。最后通過實驗測試確定并驗證軌道滑移系數(shù)，以改善系統(tǒng)的跟蹤性能。 ResQuake已經(jīng)參加幾個救援機器人聯(lián)賽。
關(guān)鍵詞：移動機器人，遠程操作，運動機制，控制結(jié)構(gòu)，滑移估計
1 引言
由一個或多個操縱器平臺組成的移動操縱型機器人有無限的工作空間。因此，各種行走，輪式，履帶式和飛行系統(tǒng)已被提出并成功地付諸實踐。這種系統(tǒng)被廣泛用于消防，林業(yè)，排爆，有毒廢物清理，運輸材料，空間軌道維護等會危機到人類健康安全的領(lǐng)域 [1]。因此，可以預(yù)計，不管是自動運行的還是遠程操作的移動機器，都將會在人類生活的各個不同領(lǐng)域發(fā)揮更加重要的作用。但是，在移動機器人系統(tǒng)中，基于作用于反作用原理，動力會影響到基座與操縱器的運動。因此，運動學、動態(tài)，以及對這些系統(tǒng)的控制已經(jīng)得到了廣泛的研究關(guān)注[2-5]。
地震是一種會威脅人類生命的自然事件。主震之后的余震會造成二次坍塌， 這會危及搜救人員的生命。為了盡量降低救援人員的風險，同時增加受害人生存機率，開發(fā)出一種能相互協(xié)作的機器救援隊不失為一種好的選擇。該種機器人及其操作者的任務(wù)是找到受害者并確定他們的情況，然后匯報目標在建筑物地圖上的方位[6,7]。這消息，會立即被發(fā)送至人類救援隊。對救援機器人的進一步預(yù)期，如能夠自主搜索倒塌建筑物，發(fā)現(xiàn)受害者和確定他們的環(huán)境，為幸存者提供生活用品和通信工具和布設(shè)傳感器(聲，熱，地震等)正處于課題研究中。然而，救援機器人的基本能力是它們在遭受破壞地區(qū)的機動性,這完全依賴于它們的運動系統(tǒng)和它們的維度。到目前為止已經(jīng)設(shè)計并生產(chǎn)了各救援機器人[8,9]。
本文對Khaje Nasir Toosi大學（KNTU）的ResQuake項目進行了直觀的描述，如圖1所示。首先對移動機構(gòu)的設(shè)計步驟進行詳細介紹，并確定系統(tǒng)尺寸和相關(guān)參數(shù)。然后是對系統(tǒng)運動學和動力學進行探討，并提出對每個機構(gòu)部件應(yīng)力分析問題。接著是敘述機器人控制系統(tǒng)。最后通過實驗測試確定并驗證軌道滑移系數(shù)，以改善系統(tǒng)的跟蹤性能。ResQuake有著友好的人機操作界面，它在非結(jié)構(gòu)化環(huán)境、不光滑的路徑，甚至是在爬樓梯時都有很強的移動能力。它的性能已被如下事實證明：在2005年日本大阪機器人世界杯救援機器人聯(lián)賽中取得第二個最佳設(shè)計獎，2006年在德國不來梅機器人世界杯足球賽中取得最佳操作界面獎，以及2008年在中國蘇州機器人杯大賽中取得第二個最佳移動獎。
圖1 ResQuake在不同的環(huán)境中運動：(左)折疊路徑,(右)爬上不平斜坡可擴展軌跡
2 機構(gòu)設(shè)計
以移動形式劃分，搜救機器人主要有三類，即輪式，履帶式和行走機器人。輪式機器人，可以在搜索平坦的區(qū)域時使用。由于動力簡單，開發(fā)這些自動系統(tǒng)相對容易。輪式機器人還能夠攀爬高度比車輪小的障礙物。履帶式機器人由于具有在崎嶇不平的地形上移動的超強能力而得到廣泛使用。圖2展示了輪式和履帶式系統(tǒng)面臨著同樣的障礙（樓梯）?？梢钥闯?，相對較小的履帶式機器人具有相同的越障能力。
圖2 兩種運動系統(tǒng)遇到相同障礙物
行走機器人通常具有高自由度(DOFs)，故而具有高機動性。因此，這種系統(tǒng)的動力學模型及其穩(wěn)定性要比前者復(fù)雜的多。此外，這種系統(tǒng)的運行需要大量的執(zhí)行機構(gòu)和傳感器，所以他們的控制系統(tǒng)更昂貴。還應(yīng)該提到的是兩輪和行走機構(gòu)相結(jié)合的方式，這保留了兩個運動系統(tǒng)的優(yōu)點，而且避免了它們的缺點[10]。在輪式-行走混合機構(gòu)中，輪式機構(gòu)可以支撐行走機構(gòu)的重量，而行走機構(gòu)可以在崎嶇的地形上移動機器人。
不僅僅是運動系統(tǒng)類型，救援機器人的尺寸也是一個重要的問題。在一個遭受破壞的室內(nèi)環(huán)境中，可能存在一些例如倒塌的墻壁或天花板一類的一般系統(tǒng)不能輕易通過的障礙。在這種情況下，機器人必須在障礙物之間尋找一條其他的路徑而不是爬過他們，這無疑取決于它的大小。一個相對較小的機器人能夠輕易地通過一條狹窄通道并繼續(xù)搜索。應(yīng)當指出，樓梯是室內(nèi)環(huán)境的一個不可分割的一部分。不管樓梯破壞與否，救援機器人都應(yīng)該有能力上下樓梯以搜查整個地區(qū)。
為了在這兩個矛盾之間進行折衷，人們提出了一種具有高機動性的小機器人，履帶式機構(gòu)已經(jīng)被應(yīng)用于ResQuake的研制。這種機制包括一個主體(基座)和兩個可擴展履帶(臂)。這一布置使機器人能根據(jù)它遇到的障礙調(diào)整自身大小。因此，相應(yīng)的，履帶應(yīng)該有一個最小長度以防止失去平衡，并且能夠在沒有額外震動的情況下能在連續(xù)的樓梯上穩(wěn)定的運動，如圖3(a)所示,。另一方面,長的履帶,例如那些簡單的履帶機器人需要一個較大的區(qū)域進行拐彎,如圖3(b)，這在遭受破壞的環(huán)境中很難滿足這一條件。
圖3 (a)履帶式機器人最小長度 (b)簡單的履帶式機器人最小拐彎半徑
2.1 可擴展履帶(臂)
圖4中顯示的結(jié)構(gòu),使得機器人可以擴大它的履帶長度以便通過障礙。另一方面,當機器人在穿過狹窄的通道以及需要較小體積時，其前端可以折疊。這也有助于減少轉(zhuǎn)彎半徑。最初的想法是在折疊工作臂上，以克服上述矛盾。
這個概念已經(jīng)改進了在兩邊都有一對工作臂的車輛，如圖4(b) 所示，用折疊臂來減少機器人的長度或擴大其他長度來滿足其他要求。另一個優(yōu)點是對稱結(jié)構(gòu)，該結(jié)構(gòu)使得機器人在前進和后退時運動相似，這一布置便于在受限空間內(nèi)轉(zhuǎn)彎。
其次，工作臂被布置在同一平面內(nèi)以降低機器人寬度(圖5 (b))。最后，為了在工作臂折疊時使用額外的區(qū)域空間，在每個臂中安裝了連接件(圖5 (b))。因此,機器人兩邊的履帶都能伸展成三個平行層面,這提供了更有效的牽引力。
圖4 (a)前端履帶初步設(shè)計 (b)具有兩對臂的改進設(shè)計 (前端和后端)
圖5（a）使履帶共線以減少機器人寬度 (b)履帶最終結(jié)構(gòu)
在系統(tǒng)中添加四個獨立的（主動）關(guān)節(jié)會增加執(zhí)行機構(gòu)的數(shù)量從而增加系統(tǒng)的總價格。因此，人們用行星齒輪系來簡化每個臂上主連接件到次連接件的功率傳輸。每個臂上的兩個的旋轉(zhuǎn)是相互獨立的。通過分析兩個臂的輪廓可以得出齒輪傳動比；（i）完全伸展（ii）完全折疊，這樣，在那些具有兩個輪廓的預(yù)期平面上的臂就可以運動(圖6)。
圖6 臂的運動軌跡
如圖6所示，當工作臂的主體部分旋轉(zhuǎn)∏/ 2rad時，從屬部分的旋轉(zhuǎn)角度應(yīng)該超過∏rad。具備這一性能的齒輪系應(yīng)該是一個行星變速箱。第一個工作臂的主體部分在行星輪系中起著工作臂的作用，其動力由電動機直接提供。太陽輪連接在機器人上的主體之上，行星輪連接到在工作臂的從屬結(jié)構(gòu)上。一對中間齒輪安裝在太陽輪和行星輪之間，該處齒輪的直徑不得超過履帶主輪直徑這一閾值（圖7）。這一機構(gòu)的另一個優(yōu)點是工作臂的兩個連接點處的中心距離在旋轉(zhuǎn)時將保持不變。這使得我們能夠補償主履帶和裝有另一履帶的工作臂之間的間隙。這種履帶的作用是將履帶主體部分上的動力傳遞至工作臂上的從屬履帶上。
圖7 個行星傳動鏈
斜齒輪由于剛度大且齒輪輪齒強度相比于直齒圓柱齒輪來說更強而被用在行星齒輪系中[11,12]。臂的角速度應(yīng)低于2至4轉(zhuǎn)每分鐘，而電機的輸出速度為3000轉(zhuǎn)每分鐘。因此電機與連桿之間的速比約為1000。三級行星齒輪變速箱這以組合結(jié)構(gòu)的每一級的比率皆為3：1 (推定直角在角速度相對較大電機軸處）的比例。傳動比為30:1的蝸輪系為受限空間提供了理想的傳動比（圖8）。機器人的兩側(cè)履帶都是直流電機驅(qū)動。
圖8 最終設(shè)計的布置
2.2 履帶
移動系統(tǒng)的牽引力在很大程度上依賴于機器人行走時履帶表面與接觸面之間的摩擦。因此履帶部件的材料和形狀就顯得尤為重要[13]。另一方面履帶應(yīng)該承受適當?shù)膹埦o力。設(shè)計的履帶由兩個主要部件組成。鏈齒結(jié)構(gòu)為系統(tǒng)提供了足夠的張緊力,由乳膠做成的齒形零部件則補償了鏈與接觸面之間的隙，從而得到所需的摩擦力。通過用長銷釘替換標準鏈中的銷釘對金屬鏈進行了修正。圖9展示了修正后的鏈以及履齒是如何安裝在這些銷釘上的。
當系統(tǒng)需要快速機動的穿過或是爬過某個斜坡時，產(chǎn)生了一個嚴重的問題，那就是由于基座運動而導(dǎo)致的不穩(wěn)定性及傾覆[14]。懸架結(jié)構(gòu)具備兩個主要優(yōu)點。
懸架系統(tǒng)包括主體上的兩個表面，并將它們通過回轉(zhuǎn)副連接起來（圖9）。一對線性彈簧限制了旋轉(zhuǎn)角度，同時使得該系統(tǒng)在未受到額外施加的作用力時保持理想姿勢。在此指出一點，該系統(tǒng)不需要使用減震器，因為作為轉(zhuǎn)動副的滑動軸承產(chǎn)生的摩擦力足以限制彈簧的額外震動。
圖9 上圖：安裝在鏈上的乳膠零件；下圖：懸掛系統(tǒng)基本結(jié)構(gòu)
2.3 最終尺寸
移動結(jié)構(gòu)設(shè)計完成后開始進行尺寸設(shè)計。一些諸如金屬鏈和行星輪一類的零件作為標準間很容易得到，所以其他零件的尺寸應(yīng)該與它們相匹配。除此之外，在計算時必須考慮機器人的整體尺寸和齒輪系的公式。由于大量的方程式共同決定著參數(shù)，人工計算無法得到最優(yōu)解。所以可以通過MATLAB來解方程得出最優(yōu)解。該過程需要考慮的尺寸列在圖10和表1中。
圖10 主要的長度確定其他維度
表1尺寸參數(shù)的機器人
… … 附件2：外文原文（復(fù)印件）
ResQuake: A Tele-Operative Rescue Robot
The design procedure of ResQuake as a tele-operative rescue robot and its dynamics analysis, manufacturing procedure, control system, and slip estimation for performance improvement are discussed. First, the general task to be performed by the robot is defined, and various mechanisms to form the basic structure of the robot are discussed. Choosing the appropriate mechanisms, geometric dimensions, and mass properties are detailed to develop kinematic and dynamic models for the system. Next, the strength of
each component is analyzed to finalize its shape, and the mechanism models are presented. Then, the control system is briefly described, which includes the operator’s PC as the master processor, and the laptop installed on the robot as the slave processor. Finally, slip coefficients of tracks are identified and validated by experimental tests to improve the system tracking performance. ResQuake has participated with distinction in several rescue robot leagues. [DOI: 10.1115/1.3179117]
Keywords: mobile robots, tele-operative, locomotion mechanisms, control architecture, slippage estimation
1 Introduction
Mobile manipulators, which consist of a platform and one or more manipulators, have an unlimited workspace. Therefore, various legged, wheeled, tracked, and flying systems have been proposed, and successfully put into practice. Such systems are used in different kinds of fields such as fire fighting, forestry, deactivating bombs, toxic waste cleanup, transportation of materials, space onorbit services, and similar applications in which human health is endangered [1]. So, it is expected that mobile robots, whether autonomous or tele-operative, play a more important role in different fields of human life. However, in a mobile robotic system, dynamic forces affect the motion of the base and the manipulators, based on the action and reaction principle. Therefore, kinematics, dynamics, and control of such systems have received extensive research attention [2–5].
Earthquake is a natural incident, which threatens human life. Aftershocks occurring a while after the main earthquake cause secondary collapses and may take victims away from the search and rescue personnel. In order to minimize the risks for rescuers, while increasing victim survival rates, exploiting fielding teams of collaborative robots is a good alternative. The mission for the robots and their operators would be to find victims, determine their situation, and then report their findings based on a map of the building [6,7]. This information will immediately be given to human rescue teams. Further expectations of rescue robots such as being able to autonomously search collapsed structures, finding victims and ascertain their conditions, delivering sustenance and communications to the victims, and emplacing sensors (acoustic, thermal, seismic, etc.) are ongoing research subjects. Nevertheless, the basic capability of rescue robots is their maneuverability in destructed areas, which thoroughly depends on their locomotion system and their dimensions. Various rescue robots were designed and manufactured so far [8,9].
This paper presents an illustrative description of the ResQuake project at Khaje Nasir Toosi University (KNTU), as shown in Fig. 1. First, designing procedure for the locomotion mechanism will be detailed, and the system dimensions and related parameters are determined. Next, the system kinematics and dynamics is discussed, and the sequence of stress analysis for each member of the mechanism is addressed. Then, the robot control system is described. Finally, slip coefficients are identified and validated by
various tests to improve the system tracking performance. ResQuake has great capabilities for moving in unstructured environment, on rough trains, and even climbing stairs, with a user-friendly operative interface. Its performance has been demonstrated in the rescue robot league of RoboCup 2005 in Osaka, Japan, achieving the second best design award, RoboCup 2006 in
Bremen, Germany, achieving the best operator interface award, and RoboCup 2008 in Suzhou, China, achieving the second best award for mobility.
Fig. 1 ResQuake in different conditions;(left)folded tracks,(right)extended tracks climbing up a ramp uneven surface
2 Mechanism Design
There are three major categories of search and rescue robots in terms of their locomotion system, i.e., wheeled, tracked, and legged robots. Wheeled robots could be considered for searching flat areas. Developing the autonomy for these systems is easier due to their simple dynamics. A wheeled robot is also capable of climbing obstacles with a height smaller than their wheels. Tracked robots are used mostly because of their great ability to move on uneven terrains. Figure 2 shows wheeled and tracked systems facing the same obstacle _stair_. It can be seen that a smaller tracked robot has the same capability.
Fig. 2 Two types of locomotion systems encountering the same obstacle
Legged robots usually possess high degrees of freedom (DOFs), and thus, high maneuverability. Consequently, dynamics modeling and stability of such systems is more complicated than the former types. Besides, implementation of such systems requires numerous actuators and sensors, so their control is more expensive. It should be also mentioned that with a combination of
the two wheeled and legged mechanisms, advantages of both locomotion systems can be preserved while shortcomings are prevented (10). In a hybrid wheel-legged mechanism, wheeled mechanism can support the weight of the legged mechanism, while the legged mechanism can move the robot on a rough terrain.
Regardless of the type of locomotion system, the size of a rescue robot is also an important issue. In a destructed indoor environment, some obstacles may exist such as collapsed walls or ceilings that cannot be easily passed by usual systems. In such situations, the robot should search for a bypass or a way between the obstacles rather than climbing over them; that definitely depends on its size. A relatively small robot can easily pass a narrow passageway and continue its search. It should be noted that stairways are an inseparable part of an indoor environment. Whether destructed or not, a rescue robot should have the ability to climb up and down stairways in order to search the whole area.
In order to compromise between the two contradictory aspects of providing a small robot with high maneuverability, a tracked mechanism has been developed for ResQuake. This mechanism includes a main body (base) with two expandable tracks (arms). This arrangement enables the robot to resize depending on the situation it encounters. Accordingly, these tracks should have a minimum length to prevent loosing its balance, and having a steady movement on successive stairs without extra vibrations, as shown in Fig. 3(a). On the other hand, lengthy tracks such as those of a simple track robot will require a wide area for turning, as shown in Fig. 3(b), which is rarely available in a destructed environment.
Fig. 3 (a) Minimum length for tracks of the robot and (b) minimum turning radius of a simple track robot
2.1 Expandable Tracks(Arms)
The structure shown in Fig. 4 enables the robot to expand the length of its tracks to pass through obstacles. On the other hand, when the robot is going through narrow passages and needs to be rather small, the front tracks can be folded. This helps with reducing the turning radius as well. Folding arms was the original idea, developed to overcome the aforementioned contradiction.
This concept has been improved to a system with two pairs of arms at both sides of the vehicle, as shown in Fig. 4(b), to reduce the length of the robot with folded arms while the expanded length fulfills other requirement. Another advantage would be the symmetry of the structure, which enables the robot to move equivalently in both forward and backward directions. This arrangement facilitates turning in a confined space.
Next, the arms are placed in the same plane to reduce the robot width (Fig. 5_a). Finally, another joint is added to each arm in order to use an extra area between the arms when they are folded, Fig. 5(b). Therefore, the tracks on each side of the robot are stretched into three parallel planes, which provide a more efficient traction.
Fig. 4 (a) Preliminary design of just front tracks (arm) and (b) improved design with two pairs of arms (front and rear)
Fig. 5 (a) Making the tracks collinear to reduce the width of robot and (b) final mechanism chosen for the tracks
Adding four independent (active) joints to the system would increase the number of actuators and consequently the total price of the system. Therefore, a planetary gear set has been used to simply transmit the power of the main joint of each arm to its second joint. So, rotation of the two parts for each arm will be dependent. The gear ratio is obtained, considering two desirable configurations of the arms; (i) fully stretched and (ii) fully folded, such that the arms can move, based on a desired plan between these two configurations (Fig. 6).
Fig. 6 The path for motion of the arms
As shown in Fig. 6, for a pai/2 rad rotation of the main part of arm, the second part should rotate more than pai rad. The gear chain with such performance should be a planetary gearbox. The main part of the first arm plays the role of the arm in the planetary chain, which is directly powered by a motor. The sun gear should be attached to the main body of the robot, and the planet gear is attached to the second part of the arm. A pair of medium gears is placed between the sun and the planet where the diameter of gears does not exceed a given threshold, which is the diameter of the main wheels of the tracks (Fig. 7). Another advantage of this mechanism is that the center distance of the two joints of the arm will remain constant during its rotation. This enables us to fill the gap between the main track, and the arm with another track. This track is used to transmit power from the main part of the tracks to the second part on the arm.
Fig. 7 Planetary gear chain
Helical gears are chosen for the planetary gear set, due to their small backlash and higher strength of gear tooth comparing with spur gears [11, 12]. The angular velocity of the arm should be less than 2–4 rpm. The motor’s output velocity is 3000 rpm. Hence, the velocity ratio between the motor and the link should be approximately 1000. A combination of a three stage planetary gearbox (constructed right at the motor shaft where the angular velocity is relatively high) with a ratio of 3:1 at each stage, and a worm gear set with a ratio of 30:1 provides the desirable ratio in a limited available space (Fig. 8). A dc motor drives the tracks at each side of the robot.
Fig. 8 Final designed arrangement for the arms
2.2 Tracks
The traction of the locomotion system strongly depends on the friction between the track pieces and the surface on which the robot moves. Therefore, the material and the shape of the track pieces are of great importance [13]. On the other hand, the tracks should also bear a reasonable tension. Designed tracks are made of two main parts. A basis of chain-sprocket provides the system with sufficient tensile strength, and tooth shaped pieces made of latex fills the gap between the chain and the surface to create the required friction. Metal chains have been modified by replacing pins of the standard chain with longer pins, and the latex grousers are mounted directly on them. Figure 9 shows modified chains and how the grousers are mounted on these pins.
One of the most important problems caused by base movement, when the system undergoes a fast maneuver or tries to climb a slopped terrain, is the instability problem or tipping over [14]. Noting this, two major advantages are obtained by including a suspension mechanism.
The suspension system was designed by containing two surfaces on the main body, and then attaching them by a revolute joint (Fig. 9). A pair of linear springs limits the angle of rotation and makes the system remain at a desired position when no extra forces are applied. It should be mentioned that the use of dampers was not needed because the friction of the sliding bearings used as the so-called joints was enough to limit any extra shaking of the springs.
Fig. 9 Top: latex pieces fixed on the chain; bottom: basic structure of the suspension system
2.3 Final Dimensions
Finishing the design of locomotion mechanisms, the dimensions are to be determined. Some of the components like metal chains and sprockets are available as standard parts, so that other dimensions should match their counterparts. Besides, the overall size of the robot and the formulas on the gear chains must be considered in the calculations. Since numerous equations govern these factors, an optimized solution is not reachable by manual calculations. Thus, MATLAB has been used to find the desired values from a set of equations. The main dimensions considered in this procedure are shown in Fig. 10 and summarized in Table 1.
Fig. 10 Main lengths for determining the other dimensions
Table 1 Dimensional parameters of robot
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