【機(jī)械類畢業(yè)論文中英文對(duì)照文獻(xiàn)翻譯】ResQuake：遠(yuǎn)程操作救援機(jī)器人【PDF英文11頁word中文翻譯3633字7頁】【有出處】
【機(jī)械類畢業(yè)論文中英文對(duì)照文獻(xiàn)翻譯】ResQuake：遠(yuǎn)程操作救援機(jī)器人【PDF英文11頁word中文翻譯3633字7頁】【有出處】,機(jī)械類畢業(yè)論文中英文對(duì)照文獻(xiàn)翻譯,PDF英文11頁,word中文翻譯3633字7頁,有出處,機(jī)械類,畢業(yè)論文,中英文,對(duì)照,對(duì)比,比照,文獻(xiàn),翻譯,resquake,遠(yuǎn)程,操作,救援,救濟(jì),營(yíng)救,機(jī)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
… …
附件1：外文資料翻譯譯文
ResQuake：遠(yuǎn)程操作救援機(jī)器人
ResQuake作為一種遠(yuǎn)程操作救援機(jī)器人，它的設(shè)計(jì)程序以及對(duì)其動(dòng)態(tài)分析，生產(chǎn)過程，控制系統(tǒng)，防滑性能改進(jìn)等一直被人們所探討。人們首先要探討的問題是規(guī)定機(jī)器人要完成的總?cè)蝿?wù)以及組成機(jī)器人基本結(jié)構(gòu)的各種機(jī)構(gòu)。選擇適當(dāng)?shù)臋C(jī)構(gòu)、幾何尺寸、對(duì)質(zhì)量進(jìn)行定性分析以形成系統(tǒng)的運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)模型。其次是對(duì)每個(gè)構(gòu)建的強(qiáng)度進(jìn)行分析以最終定型并提出機(jī)構(gòu)模型。接著對(duì)控制系統(tǒng)進(jìn)行簡(jiǎn)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(jī)器人身上作為從處理器的便攜式電腦。最后通過實(shí)驗(yàn)測(cè)試確定并驗(yàn)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(gè)救援機(jī)器人聯(lián)賽。
關(guān)鍵詞：移動(dòng)機(jī)器人，遠(yuǎn)程操作，運(yùn)動(dòng)機(jī)制，控制結(jié)構(gòu)，滑移估計(jì)
1 引言
由一個(gè)或多個(gè)操縱器平臺(tái)組成的移動(dòng)操縱型機(jī)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(shí)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(yùn)輸材料，空間軌道維護(hù)等會(huì)危機(jī)到人類健康安全的領(lǐng)域 [1]。因此，可以預(yù)計(jì)，不管是自動(dòng)運(yùn)行的還是遠(yuǎn)程操作的移動(dòng)機(jī)器，都將會(huì)在人類生活的各個(gè)不同領(lǐng)域發(fā)揮更加重要的作用。但是，在移動(dòng)機(jī)器人系統(tǒng)中，基于作用于反作用原理，動(dòng)力會(huì)影響到基座與操縱器的運(yùn)動(dòng)。因此，運(yùn)動(dòng)學(xué)、動(dòng)態(tài)，以及對(duì)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(huì)威脅人類生命的自然事件。主震之后的余震會(huì)造成二次坍塌， 這會(huì)危及搜救人員的生命。為了盡量降低救援人員的風(fēng)險(xiǎn)，同時(shí)增加受害人生存機(jī)率，開發(fā)出一種能相互協(xié)作的機(jī)器救援隊(duì)不失為一種好的選擇。該種機(jī)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(bào)目標(biāo)在建筑物地圖上的方位[6,7]。這消息，會(huì)立即被發(fā)送至人類救援隊(duì)。對(duì)救援機(jī)器人的進(jìn)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(jī)器人的基本能力是它們?cè)谠馐芷茐牡貐^(qū)的機(jī)動(dòng)性,這完全依賴于它們的運(yùn)動(dòng)系統(tǒng)和它們的維度。到目前為止已經(jīng)設(shè)計(jì)并生產(chǎn)了各救援機(jī)器人[8,9]。
本文對(duì)Khaje Nasir Toosi大學(xué)（KNTU）的ResQuake項(xiàng)目進(jìn)行了直觀的描述，如圖1所示。首先對(duì)移動(dòng)機(jī)構(gòu)的設(shè)計(jì)步驟進(jìn)行詳細(xì)介紹，并確定系統(tǒng)尺寸和相關(guān)參數(shù)。然后是對(duì)系統(tǒng)運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)進(jìn)行探討，并提出對(duì)每個(gè)機(jī)構(gòu)部件應(yīng)力分析問題。接著是敘述機(jī)器人控制系統(tǒng)。最后通過實(shí)驗(yàn)測(cè)試確定并驗(yàn)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(jī)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(shí)都有很強(qiáng)的移動(dòng)能力。它的性能已被如下事實(shí)證明：在2005年日本大阪機(jī)器人世界杯救援機(jī)器人聯(lián)賽中取得第二個(gè)最佳設(shè)計(jì)獎(jiǎng)，2006年在德國(guó)不來梅機(jī)器人世界杯足球賽中取得最佳操作界面獎(jiǎng)，以及2008年在中國(guó)蘇州機(jī)器人杯大賽中取得第二個(gè)最佳移動(dòng)獎(jiǎng)。
圖1 ResQuake在不同的環(huán)境中運(yùn)動(dòng)：(左)折疊路徑,(右)爬上不平斜坡可擴(kuò)展軌跡
2 機(jī)構(gòu)設(shè)計(jì)
以移動(dòng)形式劃分，搜救機(jī)器人主要有三類，即輪式，履帶式和行走機(jī)器人。輪式機(jī)器人，可以在搜索平坦的區(qū)域時(shí)使用。由于動(dòng)力簡(jiǎn)單，開發(fā)這些自動(dòng)系統(tǒng)相對(duì)容易。輪式機(jī)器人還能夠攀爬高度比車輪小的障礙物。履帶式機(jī)器人由于具有在崎嶇不平的地形上移動(dòng)的超強(qiáng)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）?？梢钥闯觯鄬?duì)較小的履帶式機(jī)器人具有相同的越障能力。
圖2 兩種運(yùn)動(dòng)系統(tǒng)遇到相同障礙物
行走機(jī)器人通常具有高自由度(DOFs)，故而具有高機(jī)動(dòng)性。因此，這種系統(tǒng)的動(dòng)力學(xué)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(yùn)行需要大量的執(zhí)行機(jī)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(jī)構(gòu)相結(jié)合的方式，這保留了兩個(gè)運(yùn)動(dòng)系統(tǒng)的優(yōu)點(diǎn)，而且避免了它們的缺點(diǎn)[10]。在輪式-行走混合機(jī)構(gòu)中，輪式機(jī)構(gòu)可以支撐行走機(jī)構(gòu)的重量，而行走機(jī)構(gòu)可以在崎嶇的地形上移動(dòng)機(jī)器人。
不僅僅是運(yùn)動(dòng)系統(tǒng)類型，救援機(jī)器人的尺寸也是一個(gè)重要的問題。在一個(gè)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(jī)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(gè)相對(duì)較小的機(jī)器人能夠輕易地通過一條狹窄通道并繼續(xù)搜索。應(yīng)當(dāng)指出，樓梯是室內(nèi)環(huán)境的一個(gè)不可分割的一部分。不管樓梯破壞與否，救援機(jī)器人都應(yīng)該有能力上下樓梯以搜查整個(gè)地區(qū)。
為了在這兩個(gè)矛盾之間進(jìn)行折衷，人們提出了一種具有高機(jī)動(dòng)性的小機(jī)器人，履帶式機(jī)構(gòu)已經(jīng)被應(yīng)用于ResQuake的研制。這種機(jī)制包括一個(gè)主體(基座)和兩個(gè)可擴(kuò)展履帶(臂)。這一布置使機(jī)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(gè)最小長(zhǎng)度以防止失去平衡，并且能夠在沒有額外震動(dòng)的情況下能在連續(xù)的樓梯上穩(wěn)定的運(yùn)動(dòng)，如圖3(a)所示,。另一方面,長(zhǎng)的履帶,例如那些簡(jiǎn)單的履帶機(jī)器人需要一個(gè)較大的區(qū)域進(jìn)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(jī)器人最小長(zhǎng)度 (b)簡(jiǎn)單的履帶式機(jī)器人最小拐彎半徑
2.1 可擴(kuò)展履帶(臂)
圖4中顯示的結(jié)構(gòu),使得機(jī)器人可以擴(kuò)大它的履帶長(zhǎng)度以便通過障礙。另一方面,當(dāng)機(jī)器人在穿過狹窄的通道以及需要較小體積時(shí)，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(gè)概念已經(jīng)改進(jìn)了在兩邊都有一對(duì)工作臂的車輛，如圖4(b) 所示，用折疊臂來減少機(jī)器人的長(zhǎng)度或擴(kuò)大其他長(zhǎng)度來滿足其他要求。另一個(gè)優(yōu)點(diǎn)是對(duì)稱結(jié)構(gòu)，該結(jié)構(gòu)使得機(jī)器人在前進(jìn)和后退時(shí)運(yùn)動(dòng)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(jī)器人寬度(圖5 (b))。最后，為了在工作臂折疊時(shí)使用額外的區(qū)域空間，在每個(gè)臂中安裝了連接件(圖5 (b))。因此,機(jī)器人兩邊的履帶都能伸展成三個(gè)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(jì) (b)具有兩對(duì)臂的改進(jìn)設(shè)計(jì) (前端和后端)
圖5（a）使履帶共線以減少機(jī)器人寬度 (b)履帶最終結(jié)構(gòu)
在系統(tǒng)中添加四個(gè)獨(dú)立的（主動(dòng)）關(guān)節(jié)會(huì)增加執(zhí)行機(jī)構(gòu)的數(shù)量從而增加系統(tǒng)的總價(jià)格。因此，人們用行星齒輪系來簡(jiǎn)化每個(gè)臂上主連接件到次連接件的功率傳輸。每個(gè)臂上的兩個(gè)的旋轉(zhuǎn)是相互獨(dú)立的。通過分析兩個(gè)臂的輪廓可以得出齒輪傳動(dòng)比；（i）完全伸展（ii）完全折疊，這樣，在那些具有兩個(gè)輪廓的預(yù)期平面上的臂就可以運(yùn)動(dòng)(圖6)。
圖6 臂的運(yùn)動(dòng)軌跡
如圖6所示，當(dāng)工作臂的主體部分旋轉(zhuǎn)∏/ 2rad時(shí)，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(gè)行星變速箱。第一個(gè)工作臂的主體部分在行星輪系中起著工作臂的作用，其動(dòng)力由電動(dòng)機(jī)直接提供。太陽輪連接在機(jī)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(duì)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(jī)構(gòu)的另一個(gè)優(yōu)點(diǎn)是工作臂的兩個(gè)連接點(diǎn)處的中心距離在旋轉(zhuǎn)時(shí)將保持不變。這使得我們能夠補(bǔ)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(dòng)力傳遞至工作臂上的從屬履帶上。
圖7 個(gè)行星傳動(dòng)鏈
斜齒輪由于剛度大且齒輪輪齒強(qiáng)度相比于直齒圓柱齒輪來說更強(qiáng)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(jī)的輸出速度為3000轉(zhuǎn)每分鐘。因此電機(jī)與連桿之間的速比約為1000。三級(jí)行星齒輪變速箱這以組合結(jié)構(gòu)的每一級(jí)的比率皆為3：1 (推定直角在角速度相對(duì)較大電機(jī)軸處）的比例。傳動(dòng)比為30:1的蝸輪系為受限空間提供了理想的傳動(dòng)比（圖8）。機(jī)器人的兩側(cè)履帶都是直流電機(jī)驅(qū)動(dòng)。
圖8 最終設(shè)計(jì)的布置
2.2 履帶
移動(dòng)系統(tǒng)的牽引力在很大程度上依賴于機(jī)器人行走時(shí)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(dāng)?shù)膹埦o力。設(shè)計(jì)的履帶由兩個(gè)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(bǔ)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(zhǎng)銷釘替換標(biāo)準(zhǔn)鏈中的銷釘對(duì)金屬鏈進(jìn)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(dāng)系統(tǒng)需要快速機(jī)動(dòng)的穿過或是爬過某個(gè)斜坡時(shí)，產(chǎn)生了一個(gè)嚴(yán)重的問題，那就是由于基座運(yùn)動(dòng)而導(dǎo)致的不穩(wěn)定性及傾覆[14]。懸架結(jié)構(gòu)具備兩個(gè)主要優(yōu)點(diǎn)。
懸架系統(tǒng)包括主體上的兩個(gè)表面，并將它們通過回轉(zhuǎn)副連接起來（圖9）。一對(duì)線性彈簧限制了旋轉(zhuǎn)角度，同時(shí)使得該系統(tǒng)在未受到額外施加的作用力時(shí)保持理想姿勢(shì)。在此指出一點(diǎn)，該系統(tǒng)不需要使用減震器，因?yàn)樽鳛檗D(zhuǎn)動(dòng)副的滑動(dòng)軸承產(chǎn)生的摩擦力足以限制彈簧的額外震動(dòng)。
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(dòng)結(jié)構(gòu)設(shè)計(jì)完成后開始進(jìn)行尺寸設(shè)計(jì)。一些諸如金屬鏈和行星輪一類的零件作為標(biāo)準(zhǔn)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(jì)算時(shí)必須考慮機(jī)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(jì)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(zhǎng)度確定其他維度
表1尺寸參數(shù)的機(jī)器人
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