1、 SMALL-SIZE WINDOW CLEANING ROBOT BY WALL CLIMBING MECHANISM1. INTRODUCTIONRecently, there have been many demands for automatic cleaning system on outside surface of buildings such as window glass by increasing of modern architectures. Some customized window cleaning machines have already been insta

2、lled into the practical use in the field of building maintenance. However, almost of them are mounted on the building from the beginning and they needs very expensive costs. Therefore, requirements for small, lightweight and portable window cleaning robot are also growing in the field of building ma

3、intenance. As the results of surveying the requirements for the window cleaning robot, the following points are necessary for providing the window cleaning robot for practical use:1) It should be small size and lightweight for portability.2) Clean the corner of window because fouling is left there o

4、ften.3) Sweep the windowpane continuously to prevent from making striped pattern on a windowpane4) Automatic operation during moving on the window.The locomotion mechanism must be chosen to satisfy these demands, especially later two subjects. Here locomotion mechanism means the combination of adher

5、ing mechanism, traveling mechanism and a mechanism for changing a traveling direction.First requirement brought the following specifications for designing the window cleaning robot.Weight: less than 5kg, including the weight of battery and washing water,Size: 300mm x 300mm x 100mm.These were also de

6、fined by the results of surveying the demands from the cleaning companies. In previous researches, we have proposed outline of mechanical system for window cleaning robot for filling above mentioned demands. And we confirmed basic properties and its possibility by the experiments. That mechanical sy

7、stem consists of two-wheel centered differential drive specialized in making a right-angled turn at the corner of window and a suction cup with vacuum pomp as adhering method. By this mechanical system, window cleaning robot can move onvertical window with adhering smoothly. Fig. 1 is the rendering

8、at a scene of practical use of proposed window cleaning robot. This robot adheres on a windowpane with cleaning as moving on large windows.This paper deals with traveling control system in order that above mentioned mechanical system of window cleaning robot can be operated automatically. We know a

9、lot of studies on wall climbing robot including window cleaning robot by various research groups1-10, but there are few researches and development of motion control of wall climbing robot. However the environment of robot which moves on vertical or inclined plane is quite different from the robot mo

10、ves on horizontal plane at conditions of motion control. This is due to difference of direction of Fig. 1 Rendering of small-size window cleaning robot gravity works on the robot.Fig. 1 Rendering of small-size window cleaning robotIn this paper, we explain window cleaning robot installed traveling c

11、ontrol system and report results of basic traveling experiments and autonomous wiping motion on vertical window majored quantitatively. This paper includes four chapters. The second chapter illustrates prototyped mechanical systems used for experiments and moving path of window cleaning. The third c

12、hapter shows experimental result of basic traveling control and window wiping motion by comparing to with or without of motioned control system and says some discussions in each experiment. And the third chapter The forth chapter gives a conclusion. 2. MECHANICAL SYSTEMSIn this study, we use climbin

13、g mechanism which consists of the two-wheel locomotion mechanism and adhering mechanism by a suction cup. This mechanism is reported in previous researches 11. This mechanism was designed under focusing on the window cleaning robot for just a single windowpane. It is apparently necessary to cross ov

14、er the window frame or joint line to use it at any window, but the single windowpanes like as a show window also exist as an important application.A. Traveling path In order to sweep all over the window plane, two types of traveling paths shown in Fig. 2 were considered. Here we adopted type (A) in

15、Fig. 2 because of energy efficiency and cleaning affectivity. Type (A) in Fig. 2 principally involves horizontal direction movements. The robot will climb up just once. On the other hand path of type (B) consists of mainly vertical direction movements, i.e. the robot must continue to climb up and go

16、 down the window recursively. Therefore type (A) is better on energy efficiency. And further, we must remember that the robot has a possibility to be in damage of bringing pollutions to where cleaned already, if the robot moves along the path of type (B). B. Locomotion Mechanism and robot bodyThe ro

17、bot moves on windowpane by two-wheel locomotion mechanism with holing the body on the surface using a suction cup vacuumed by a pump. The mostimportant point in the mechanism is the friction coefficient of suction cup and tire against the adhering surface, e.g. high friction between the tire and the

18、 surface of window can transmits the torque, and low friction between the suction cup and the surface of window can achieves to move the robot with holding the body on the window. We selected PTFE (Polytetrafluoroethylene) for the materials of surfaceof a suction cup, and silicon rubber for the mate

19、rial of tires.C. Turning Mechanism and robot body Turning mechanism is a key to clean even at the corner of window. Fig. 3 shows the scenes that the robot changes its traveling direction at the corner. Fig. 3-(a) shows a usual turning way like as turning of motorcars. In this case, since the robot c

20、hanges a direction as tracing an arc, it can not reach the end of corner of window. It needs the robot can not move along desired lines. In consequence, the robot can not cover the window surface without any hole, or the robot come to dead end by going off the course therefore the robot can not cont

21、inue operation any more shown as Fig.8 It seems that this problem is caused by the gravity whose direction intersects with traveling direction of the robot at grade. It is a particular problem in traveling control of the robot moves on vertical or inclined plane like as windows. To determine this pr

22、oblem, we adopted attitude control using acceleration sensor. This chapter explains its control methods and outline of electronic system. In this control, input value is the desired attitude angle 0, output value is attitude angle of the robot which is measured by acceleration sensor whose character

23、istics are shown in Table 2 .This sensor was installed into the robot body as shown in Fig. 10. In order to control the attitude, the robot measures a direction of gravity since the related angle between gravity direction and robot body gives attitude angle. When therobot moves on the window, there

24、is a possibility that the sensor detect convoluted value both the acceleration gravity and acceleration by the motion of the robot. But the robot will be operated with static and low velocity. Therefore the acceleration by motion of the robot is ever-smaller than acceleration gravity. So, in this co

25、ntrol, we do not consider complicated process as follows to clean the corner by such robot: first, the robot goes into a corner, next it moves back the distance to turn, then it changes its direction as tracing an arc. The robot can clean a corner easily and rapidly. Round-shape robot is easily able

26、 to turn at the corner, but it unable to reach the end of corner. On the other hand, a quadrangular robot can clean to the end of corner, but never turn itself there. To get a function to change direction as shown in Figure 3-(b), we designed the mechanism that a mobile unit and a cleaning part are

27、rotatably connected at the center shaft as shown in Fig. 4.3. EXPERIMENTS AND DISCUSSIONSThis chapter reports experimental result of motion control of prototyped window cleaning robot installed attitude controller illustrated in Chapter III. This experimentconsists of two kinds of experiments. One i

28、s measurement of performance of attitude control when the robot moves to horizontal direction and elevation angle of 45 degrees. The other is an experience of window wiping operation with attitude controller on actual window glass. The robot was examined on the window stood vertically. The glass of

29、the window is flat, clear and the thickness of 8mm. The glass is held by window frame made of aluminium. In all the experiment, the motions of robot measured by digital stereo vision camera, Bumblebee. This camera system can recode absolute position coordinate of the robot by measuring the position

30、of colored light mounted on the two corners of the robot in darkroom. The experimental setups are illustrated in Fig. 9. In this experiment, electric power is supplied form batteries placed in the robot, i.e. the robot is operated without any cablesTest 1: Horizontal directionMoving of horizontal di

31、rection was measured as two conditions; one is without attitude control and the other is with attitude control using an acceleration sensor. Each experiment is measured in same position on the window, and same moving distance of 1.8 meters. At the starting point, the robot is attached on the window

32、direct to horizontal direction shown as Fig. 14-(A). Fig. 15 shows motion trajectory both controlled and uncontrolled by attitude control system. A square in the figure represents the position and attitude of robot body recorded every 1 second. Fig. 15 says that as the robot goes, its trajectory is

33、decurved. The average moving velocities of controlled case is 0.199 m/s; uncontrolled case is 0.374 m/s.The trajectory of controlled case shift 0.226m of the Y direction at goal point (X=1.80m). The trajectory of uncontrolled case shift 0.862m of the Y direction at goal point (X=1.80m).Then the atti

34、tude of uncontrolled robot inclines to clockwise as the robot runs, shown in Fig. 16. On the other hand, attitude angle of controlled robot is stabilized around 0 degree with a margin of error of plus or minus 5 degrees as shown in Fig. 16Test 2: Direction of elevation angle of 45 degreesIn this exp

35、eriment, control results of moving direction of elevation angle of 45 degrees were measured as test 1, shown in Fig 14-(B). Fig. 17 shows motion trajectory of climbing to direction of elevation angle of 45 degrees. A square in the figure represents the position and attitude of robot body recorded ev

36、ery 1 second. The average moving velocity of controlled case is 0.138 m/s; uncontrolled case is 0.153 m/s. Fig. 18 shows that attitude angle of the robot controlled is constant and stabilized at 43 degrees. On the other hand, the robot which was uncontrolled is increase up to approximately 100 degre

37、es.Test 3: Window Wiping MotionFig. 19 indicates moving trajectory of window wiping motion when the robot moved on the window toward a path shown in Fig. 8. The robot was started from the corner of lower left and climbed up toward window frame of left side, and it ran to horizontal direction toward

38、window frame of top, next, the robot went down as the distance less than length of robot body. At the each corner, the robot changed the traversing direction at right angle using specialized turning mechanism. A square in the figure represents the position and attitude of robot body recorded every 1

39、 second.4. CONCLUSION This paper described an application of small-size and light weight wall climbing robots for window cleaning. The window cleaning robot consists of two-wheel locomotion mechanism and a suction cup. This robot moved on the window smoothly with adhering by a suction cup. And this

40、robot has a function to change a traveling direction at right angle at the corner of the window. Above mentioned window cleaning robot was prototyped and its mechanism and some of characteristics were illustrated. Next, we developed attitude control system which is important technology to operate au

41、tomatically. This control system was installed into prototyped robot mentioned above. Then, in order to measure the specifications of widow cleaning robot with attitude control systems on the vertical window, some of the experiments have been done. And the trajectory of window wiping movement was re

42、corded quantitatively. As the results of these examinations, we got result that the attitude angle of robot is under control, but robot trajectory is not fit with desired trajectory perfectly. Because, a robot has errors not only attitude angle, but also error of translation motion. To solve this pr

43、oblem, we will have to obtain the way to measure those errors and it control.譯文：小型攀爬式窗戶清洗機器人1. 簡介目前，隨著玻璃外墻建筑物的增長，人們對建筑物外墻表面（特別是玻璃外墻表面）進行自動化清洗要求的需求量也越來越大，一些專用的窗戶清洗機也已經(jīng)實際運用在了建筑維護領(lǐng)域。但是，他們之中大多數(shù)都是從一開始就要一直安裝在建筑物上面，這需要很高的費用。因此，在建筑物的維護方面，我們迫切需要一種小巧、重量輕、可攜帶的窗戶清潔機器人。根據(jù)我們對窗戶清洗機器人的要求進行的調(diào)查的結(jié)果，為了滿足實際運用，其應(yīng)該必須具備以下幾

44、點要求：1) 小巧、重量輕、便于攜帶。2) 能夠清潔到的窗戶的各個角落，因為那里往往是污垢聚集地。3) 能夠連續(xù)式的清洗窗戶表面以防留下污垢走過的條痕。4) 在窗戶上能自動運行并調(diào)整前進方向。選擇的運動機制必須滿足這些條件，特別是后面兩項要求。這里的運動機制是指：與窗戶表面的附著粘合機制、路線行走機制，以及改變行進方向的機制與原理。運用于這種領(lǐng)域的機器人應(yīng)該首先滿足以下設(shè)計要求： 圖1小型窗戶清洗機器人示例 重量：不超過5kg，包括電池和清洗用水的重量。 外形尺寸： 300mm x 300mm x 100mm.這些要求也是通過對眾多清潔公司的需要進行調(diào)查而得出的。在以前的研究中，根據(jù)以上給出的

45、要求，我們已經(jīng)確定了窗戶清洗機器人機械系統(tǒng)的大致輪廓；通過實驗，我們也確定了這個機器的一些基本屬性和性能。這個機械系統(tǒng)包括一個用以保證在窗戶角落處正確轉(zhuǎn)向的兩輪差動驅(qū)動中心和一個能將機器吸附在窗戶表面的真空泵吸盤。有了這個機械系統(tǒng)，機器人就能吸附在窗戶面上平穩(wěn)垂直的行走。如圖1所示，就是窗戶機器人在實際運用過程中的動作情況，它附著在窗玻璃上邊走邊清洗窗戶表面。為了上述的清潔機器人機械系統(tǒng)能夠?qū)崿F(xiàn)自動操作，所以其行走控制系統(tǒng)是這篇文章主要的討論對象。我們知道有許多研究機構(gòu)對墻面爬行機器人，包括窗戶清洗機器人都做過許多研究。但是，墻面攀爬機器人的運動控制依然很少有大的進展。機器人在垂直平面上運動和

46、在水平面上運動所處的環(huán)境是不同的，從而其運動控制也有著很大的不同，這主要是由于其運動的方向不同，如圖1所示，小型窗戶清洗機器人工作時將受到重力的作用。這篇文章將介紹擦窗機器人的行走控制系統(tǒng)，并得出在行走實驗中其自動擦窗時垂直運動的主修定量結(jié)果。本文共有四個部分，第二部分主要介紹了實驗中清洗機原型機械系統(tǒng)和擦窗行走的路徑；第三章對清洗機器人進行了實驗，分析了其運動控制，并通過對在有運動控制系統(tǒng)和沒有運動控制系統(tǒng)時機器的運動情況作比較給出了相關(guān)結(jié)論；而第四部分則主要是作了一個總結(jié)。2. 機械系統(tǒng)在這項研究中，我們采用的攀爬機械裝置包含了一個兩輪的運動導(dǎo)向裝置和吸盤吸附裝置。這種機械裝置在之前我們已

47、經(jīng)提到過，主要是設(shè)計用于單一窗玻璃表面的清洗工作。當(dāng)然，為了有較為廣泛的應(yīng)用，機器人理應(yīng)能夠跨越窗戶邊框或連接處以適應(yīng)各種窗戶表面的清洗，但諸如像玻璃展示窗一類的單玻璃窗戶表面的清洗依然是一個很重要的應(yīng)用領(lǐng)域。A 運動路徑圖2 小型窗戶清洗機清洗路徑 為了能夠清洗到整個玻璃窗戶表面，我們考慮了兩種清洗路徑，如圖2所示?？紤]到能源效率和清潔效率的因素，這里我們采用圖2中（A）所示的路徑方案。圖2中的(A)主要是以水平運動為主，機器人將一次性爬至最高點；而（B）中的運動路徑則主要是垂直運動，機器人必須持續(xù)不斷的來回上下運動。所以，（A）所示的運動方案能更好的節(jié)約能源。除此之外，我們還必須考慮到若選

48、擇行走路徑（B），機器人有可能在剛剛清洗干凈的地方帶來二次污染。B 機械運動與機器人主體機器人通過兩個輪子在窗戶面上進行運動，而真空泵驅(qū)動真空吸盤使則得整個機器人能夠緊緊吸附在玻璃表面上不掉下來。整個機器最重要的就是吸盤以及輪胎和吸附面的摩擦系數(shù)，例如：輪胎與窗玻璃表面的高摩擦系數(shù)就會產(chǎn)生扭矩，而吸盤與玻璃表面較低的摩擦就能使得機器能緊貼在窗戶表面上。吸盤我們選擇的材料是PTFE (聚四氟乙烯)，而輪胎的材料則是硅橡膠。C 轉(zhuǎn)向機構(gòu)與機器人主體（b）新型轉(zhuǎn)向方法圖3 小型清洗機器人俯視圖（a）傳統(tǒng)轉(zhuǎn)向方法轉(zhuǎn)向機械裝置是機器能在窗戶轉(zhuǎn)角處能干凈清洗的關(guān)鍵部分。如圖3所示，顯示了機器在窗角處的運動

49、轉(zhuǎn)向情況。如圖3-（a）所示，采用的是一種常見的方法，機器人如同汽車一樣在窗角處轉(zhuǎn)向。在這種情況下，因為機器人是弧線形轉(zhuǎn)向，使得其并不能清洗到轉(zhuǎn)角的邊角處，機器人是不能按照這種運動軌跡運動的。因此，機器人并不能清洗整個玻璃表面而不留下一點漏洞，或許在轉(zhuǎn)向之前有可能會卡死在轉(zhuǎn)角處而不能繼續(xù)運動，如圖8所示。圖8 沒有姿態(tài)控制系統(tǒng)下的清洗動作情況似乎導(dǎo)致這樣的問題出現(xiàn)好像是因為重力的方向與行駛在窗戶表面的機器人的方的運動向相交所導(dǎo)致的。這個問題是機器人要能在垂直光滑的表面上（如玻璃窗）運動的一個典型的問題。為了解決這個問題，我們采用的一種加速度傳感器來調(diào)整機器人的行走姿勢。本章主要是解釋它的控制方

50、法和大致的電子控制系統(tǒng)組成。在此控制，輸入值是理想姿態(tài)角0，而輸出角的值是其與運動方向之間的夾角，它由加速度傳感器所測得，其值如表2所示。傳感器安裝在機器人的位置可見圖10。 為了能夠控制這個角度，機器人通過測量相關(guān)角度與重力方向的夾角來測得并給出正確的方向和角度。當(dāng)機器人在窗戶玻璃上移動的時候，安裝在機器人身上的傳感器就會隨時監(jiān)測機器人運動方向和其重力加速度方向錯綜復(fù)雜的值，但是，機器人的操作是很平穩(wěn)的，其運動的速度也是較低的。因此，機器人的運動加速度要比重力加速度小得多。所以，在這個控制，我們認為這種機器人要清洗拐角處并不需要考慮以下復(fù)雜的過程：首先，當(dāng)機器人到達一個角落的時候，在它移動一段距離的時候再轉(zhuǎn)過來，然后轉(zhuǎn)過一個弧線改變其前進的方向。這樣，機器人就能簡單快速的把拐角處清洗干凈。輪型機器人可以很容易地把角落處的污垢清洗干