公園湖泊水面垃圾清掃船設(shè)計-垃圾打撈收集作業(yè)（含6張CAD圖紙）
公園湖泊水面垃圾清掃船設(shè)計-垃圾打撈收集作業(yè)（含6張CAD圖紙）,公園,湖泊,水面,垃圾,清掃,設(shè)計,打撈,收集,作業(yè),CAD,圖紙
附錄一：
自動清掃湖面漂浮物船
摘要---在許多國家水面漂浮物的污染越來越嚴重，有人提議可以設(shè)計一艘自動清掃湖面漂浮物的船，這艘船是由太陽能電池供電。電池系統(tǒng)的過多充放電保護回路已被使用。超聲波檢測系統(tǒng)已被安裝在船上并且能檢測到船到湖邊的距離。船的方向和位置是由在兩次連續(xù)控制船的行駛方向使其在離岸邊不遠的環(huán)形區(qū)域內(nèi)自動行駛的時間，船到岸邊的距離確定。船上已經(jīng)安裝一個可以識別障礙物并自動避開檢測到的障礙物的系統(tǒng)。在船的兩側(cè)安裝螺旋槳來驅(qū)動船舶，可以使船舶靈活的改變方向。光敏電阻是用來確定它是在白天還是黑夜，船舶只有在夜晚環(huán)繞湖中一次就可以節(jié)省能量。無線遙控器是有用的，因為它可以使用船者更靈活方便的控制船。實驗證明了設(shè)計的適用性。
關(guān)鍵詞：自動的，漂浮物，超聲波，清掃船，污染
I. 介紹
自然湖泊和所有的人工湖泊可以使人們的生活環(huán)境變得很美?，F(xiàn)在人們的生活水平越來越高，很多人逢年過節(jié)或者在假期間，都會選擇去一些景區(qū)游玩，但是有的人素質(zhì)略顯低，在公共場所亂丟垃圾。在一些河道以及湖泊的水面上我們可以看到許多漂浮物，這些漂浮物就會使水里的空氣供應(yīng)不足，從而導(dǎo)致水里的魚最終也是漂浮在水面上，最終形成惡性循環(huán)。然而，隨著人類活動的增加，湖面上漂浮物的污染越來越嚴重。對湖面上垃圾物的污染治理越來越迫切。[1]
由此可見湖泊里的水流速度很低，有時幾乎為零，大部分漂浮物垃圾分布在湖邊的一個區(qū)域。[2]目前，所有漂浮物垃圾經(jīng)常是人工清理。[3]工作量大，花費時間久，成本貴，工作效率低。為了解決以上問題，我們已經(jīng)設(shè)計了一艘自動清掃湖面漂浮物垃圾船。如圖片1所示，一個模型船已經(jīng)被研制出來了，已進行的實驗證明了實驗的適用性。
II. 清掃船的設(shè)計
清掃船主要由太陽能電池供電，這非常經(jīng)濟性，能夠節(jié)約能源和保護環(huán)境。清掃船決定它自己的方向和位置可以以湖岸為參考系。清掃船主要是通過控制船在離湖邊不遠預(yù)設(shè)的區(qū)域內(nèi)繞著湖邊運轉(zhuǎn)。同時，清掃船可以自動清掃垃圾。當(dāng)超聲波探測到前方有障礙物，清掃船就會自動變更方向。也設(shè)計了識別白天還是黑夜的電路。清掃船只有在夜晚環(huán)繞湖面一圈就可以節(jié)省能量了。通過實際環(huán)境確定在白天清掃漂浮物垃圾循環(huán)時間。遙控電路的設(shè)計，手動控制船舶的使用，這個在一些特殊的環(huán)境下極其有用，從而可以提高船舶的實用性。一種用于收集漂浮垃圾的機械設(shè)計，實現(xiàn)自動收集漂浮垃圾。
為了實現(xiàn)以上提到的功能，垃圾清掃船需要通過微處理器來控制。它需要能源供應(yīng)系統(tǒng)，鍵盤和顯示器，障礙物檢測系統(tǒng)，船舶定位檢測系統(tǒng)，運動控制系統(tǒng)，用于識別白天和夜晚的電路，遠程控制系統(tǒng)，在圖2中可以看出，
圖2：清掃船的結(jié)構(gòu)
A：單片機微處理系統(tǒng)設(shè)計
清掃船主要SCM系統(tǒng)是由一個SCM，晶體振蕩器和一個監(jiān)視時鐘組成。SCM是AT89S52單片機，是愛特梅爾公司生產(chǎn)。它具有8K字節(jié)的芯片閃存，和256字節(jié)的RAM，兩個16位定時器/計數(shù)器，兩個外部中斷，一個全雙工UART。SCM的振蕩頻率是12MHZ，監(jiān)視時鐘在通電，斷電等其它故障時會清零。監(jiān)視時鐘是MAX813，是MAXIM公司生產(chǎn)的，這家公司專門生產(chǎn)集成電路的功率檢測和監(jiān)視時鐘定時器。
B：鍵盤和顯示組件的設(shè)計
在清掃船中，ZLG7289已應(yīng)用在鍵盤電路和顯示組件電路，這兩種電路是坐落在廣州的一家公司生產(chǎn)的。一個ZLG7289芯片可以驅(qū)動7段LED管最高顯示8為數(shù)字，條形圖顯示，或64個發(fā)光二極管和64鍵的鍵盤。它通過串行外接口[SPI]與單片機通信，并且只需要三個I/O引腳的單片機可以節(jié)約有限的資源。當(dāng)按鍵被按時，ZLG7289的鍵栓就會變低。當(dāng)讀取低電平信號時，SCM可以通過SPI總線確定鍵盤的按鍵數(shù)量。將會有八個LED數(shù)碼管顯示和六個按鍵。系統(tǒng)可以獲取LED數(shù)碼管顯示的距離值的距離檢測。六個功能鍵主要用于設(shè)置的清掃船的控制參數(shù)。
C：運動控制系統(tǒng)設(shè)計
運動控制系統(tǒng)控制清掃船在湖泊里運動。從屬系統(tǒng)可以探測到清掃船距離湖邊的距離，并通過異步串行口發(fā)送到主控制系統(tǒng)上。通過兩清掃船距離值主控制系統(tǒng)可以確定清掃船的位置和方向。在系統(tǒng)中超聲波是用來測量距離的。超聲波測距是利用反射式測距方法[5]，要測量的距離是根據(jù)在系統(tǒng)發(fā)出的超聲波和系統(tǒng)接收到回波的時間計算的。每一個測距系統(tǒng)是是由一個獨立的單片機控制發(fā)射超聲波和接收超聲波[6]。專用集成電路LM1812完成了超聲波發(fā)送任務(wù)。當(dāng)接收回波的任務(wù)由紅外接收模塊CX20106完成。當(dāng)超聲波的傳輸控制信號，單片機內(nèi)部定時器被同時啟動。集成電路CX20106在接收到回波時，外部中斷器將會停止讀取時間信號，此時會發(fā)送一個低電平信號，清掃船和物體之間的距離可以通過定時器的數(shù)據(jù)計算。清掃船上設(shè)有兩個超聲波測距系統(tǒng)，其中一個安裝在船的前面，被記為A，另一個是放置在船的右側(cè)，被標(biāo)記為B。
這兩個傳感器每隔兩秒就會測量一次船和湖邊的距離，根據(jù)兩個連續(xù)時間段內(nèi)的距離可以確定清掃船的位置和方向。有幾種不同的情況如下所述：
第一種情況是：通過A傳感器第一次和第二次測量的距離超出了額定范圍，也就是說超過3m以上，和用傳感器B所測結(jié)果是一樣的，約60厘米，此時此刻，清掃船被認為是和湖邊是平行的。
第二種情況是：通過A傳感器第一次和第二次測量的距離超出了額定范圍，因此，說明前面沒有障礙物，然而，用傳感器B測量時，第一次測量距離比第二次測量距離小，這就表明向右轉(zhuǎn)才能到達湖岸。
第三種情況是：通過A傳感器第一次和第二次測量的距離超出了額定范圍，而采用B傳感器測量時，第一次測量距離要大于第二次測量距離，這時候表明向左轉(zhuǎn)就可以抵達湖岸邊，（參見圖3 time4）。最后一種情況是：采用傳感器A的測量值不到2m，但是采用傳感器B測量時，測量值是相同的。在這種情況下，障礙可能存在于清掃船前或者湖岸邊直角方向向左。（參見圖3 time5）電機將控制相應(yīng)的功能使船在湖岸邊移動。
圖3 清掃船運動控制策略
D：避開障礙物系統(tǒng)設(shè)計
當(dāng)清掃船在湖泊上行駛時，清掃船可能會遇到障礙物，因此有可能它就會自動地避開障礙物，然后回到原來的行駛軌道。是否存在障礙在兩次超聲波測量的距離之內(nèi)，遇到障礙物或者在清掃船前面選擇靠近湖岸邊在方法上是與決定直角向左轉(zhuǎn)的方法是相似的。這也就是說通過傳感器A測量的距離是2m和通過傳感器B測得的距離是一樣的。在這種情況下，遇到障礙或者靠岸這兩種情況應(yīng)該事先被考慮，所以這艘清掃船應(yīng)該被控制直角左轉(zhuǎn)（參見圖4 time1）。當(dāng)使用傳感器A測得的距離值大于3米并且采用傳感器B測得的距離值是60厘米時，船舶開始直線行走。如果清掃船從直角向左轉(zhuǎn)時，用傳感器B測得的距離值不會改變的(參見圖4 time 5)，如果清掃船遇到障礙，采用傳感器B測得的距離會比之前測得的距離大，因為障礙是長方形的或者是弧形的。因此船會向右轉(zhuǎn)（請見圖4 time3）。直到采用傳感器B測得的距離是60厘米，這個時候清掃船會直著行駛。當(dāng)探測到要靠近湖岸邊的時候，清掃船將會在直角區(qū)域內(nèi)向左轉(zhuǎn)（請見圖4 time3）。最后由于用傳感器A測得的距離值大于3米并且采用傳感器B測得的距離值是60厘米，清掃船回到自己的特定軌道。
圖4 ：避開障礙物船的戰(zhàn)略設(shè)計
E: 辨別白天或者黑夜的電路設(shè)計
使用一個在不同的關(guān)照強度條件下，有不同的電阻值的光敏電阻，該系統(tǒng)能夠識別白天或者黑夜。當(dāng)光線較強時，電阻值較小。相反，在光線較弱時，電阻值反而很大。在辨別電路中，固定電阻器和光敏電阻器是用來區(qū)分固定電壓和被采用的參考電壓的。電壓比較器是用來確定輸出電壓的，如果被劃分的電壓比參考電壓小時，白天和夜間的識別系統(tǒng)會會決定它是在夜間，否則被認為在白天。在白天時，可以設(shè)置清洗循環(huán)頻率，而在夜間清掃船只循環(huán)一次。
F：電機控制系統(tǒng)設(shè)計
清掃船的動力包括垃圾收集傳送帶和傳動裝置，傳輸裝置和垃圾存儲裝置都具有一定的獨特設(shè)計。還有驅(qū)使清掃船行駛和靈活地變更方向的兩個螺旋槳。這些裝置全都是直流電機供能的。兩高速直流電機用于驅(qū)動兩個螺旋槳，并且編號為TA8050P專用集成電路用于控制驅(qū)動齒輪箱皮帶傳動的電機。五種控制方案的設(shè)計包括：直走，左轉(zhuǎn)彎，右轉(zhuǎn)彎，直角彎左轉(zhuǎn)，直角彎右轉(zhuǎn)。當(dāng)兩個高速電機速度控制以同樣的速度運轉(zhuǎn)時，清掃船要直線行駛。當(dāng)右邊電機加速時，清掃船將會左轉(zhuǎn)。當(dāng)左邊電機的速度保持不變時，這時清掃船會向右轉(zhuǎn)，而且會有較大的轉(zhuǎn)彎半徑。當(dāng)左側(cè)電機停止轉(zhuǎn)動，右側(cè)電機保持原來速度行駛，這時清掃船在直角轉(zhuǎn)彎時將會向左轉(zhuǎn)。相反的情況下，清掃船將會在直角轉(zhuǎn)彎向右轉(zhuǎn)。
G：遙控系統(tǒng)設(shè)計
除了鍵盤和顯示電路，遙控系統(tǒng)的設(shè)計也實現(xiàn)了手動控制清掃船的效果。無線電頻信號可以輻射四周并且中間不可有障礙物抵擋，是作為航空公司運輸遠程控制消息。遙控器可以控制距離達到500米的船，它有8個按鍵，手動模式和自動模式之間的切換鍵、控制移動方向鍵、控制驅(qū)動傳送帶的電機鍵。
H：供電系統(tǒng)設(shè)計
控制系統(tǒng)需要一個12伏電源，主要用來驅(qū)動超聲波發(fā)射器和直流電機。它還需要一個用于供電的單片機控制系統(tǒng)的5伏電源。動力來自太陽能輸出的額定功率15瓦，用來收取一個12伏/7AH免維護鉛酸蓄電池。后者是用于電力系統(tǒng)。充電過程中，電池電壓是被電力系統(tǒng)監(jiān)控的避免過放電和過充電。對于單片機的5伏的電源由一三穩(wěn)壓器穩(wěn)壓，為了避免電動機起動停止操作影響控制電路，直流與直流功率電路的設(shè)計是為了提供電源隔離。
I:程序設(shè)計
根據(jù)清掃船的工作過程，主要的SCM系統(tǒng)的程序和距離測量系統(tǒng)是模塊化結(jié)構(gòu)設(shè)計。供應(yīng)鏈管理系統(tǒng)的程序的主要包含以下模塊:項目管理電力系統(tǒng),遠程控制的程序,距離測量程序交流，控制移動方向程序，控制電機程序。圖5可以顯示供應(yīng)鏈管理系統(tǒng)流程圖，這兩個從動裝置的單片機系統(tǒng)的主要工作是實現(xiàn)超聲波測距和發(fā)送到主機的測量距離串行通信。
圖5：掌握單片機的流程圖
工作過程如下：首先是電池能量的檢測，如果電壓低于閥值，這時候船將會停下來，一個低能信號將通過LED閃過燈發(fā)出信號，如果電源電壓是正常的，它會檢查是否有按鍵被按下。被設(shè)計的鍵盤可以設(shè)定清掃船的清洗循環(huán)頻率，如果工作模式是自動的，相應(yīng)的LED燈也會自動顯示工作狀態(tài)。之后，系統(tǒng)會檢查是否有從動裝置的單片機系統(tǒng)發(fā)出數(shù)據(jù)和接受數(shù)據(jù)。接收到的數(shù)據(jù)將會有主計算機系統(tǒng)計算控制。如果這艘船在手動模式下工作，它將顯示手動狀態(tài)，并執(zhí)行控制清掃船按照鍵盤的按鍵的遙控器。
III. 清掃船的試驗性研究
我們已經(jīng)進行了試驗，包括超聲波測距，手動操作和自動操作測試。與標(biāo)準(zhǔn)的機械測量表相比，超聲波的測量精度約為1厘米時，測量距離則在25厘米和300厘米之間，自船舶運行路徑周圍形成的基礎(chǔ)上測量距離,船不能離開遠離湖的岸邊。實驗表明,該傳感器實現(xiàn)清掃船的運行過程。對于清掃船的運行不需要跟高精度。此外，這艘清掃船可以通過手動或自動方式實現(xiàn)向左轉(zhuǎn)，向右轉(zhuǎn)，直行，直角彎左轉(zhuǎn)，直角彎右轉(zhuǎn)。并且能夠成功執(zhí)行檢測障礙物和避開障礙物這種功能。然而，仍存在一些不足之處。一方面，這艘船的功能比較先進。另一方面，如果湖的岸邊曲率半徑較大時，船首先還是會慢慢地向左轉(zhuǎn)彎，然后再慢慢地直角向左轉(zhuǎn)。這時就有可能這艘船會撞到岸邊。因此，清掃船行駛的道路可能不是一帆風(fēng)順。
IV. 結(jié)束語
在這篇文章中，主要是根據(jù)湖面漂浮物垃圾的結(jié)構(gòu)和工作原理提出了垃圾清掃船。而且清掃垃圾船既可以通過手動方式來實現(xiàn)運動又可以通過自動方式達到目的。同時也提出了超聲波測距的方法。通過對湖面上的漂浮物垃圾的分布特征進行分析，提出一種方法清掃湖岸周圍的湖面漂浮垃圾。兩個超聲波測距系統(tǒng)主要是用來獲取定位的，第一定位是清掃船的方向，第二定位是清掃船的位置定位。只有在五種情況下才被編程，這艘船的運動路徑不是很順利。在更多的情況基礎(chǔ)上分析，以上五種情況可以使船的行駛情況更完美，更平行于湖岸邊。實驗已經(jīng)證明，自動清掃湖面上漂浮物垃圾船的設(shè)計是非常適用的。經(jīng)過這樣的分析設(shè)計我們將會得到一艘可以自動避開障礙物，并且能夠打撈湖面上的漂浮垃圾。這樣在效率上，就會比以前的人工打撈既省力又省時。另外，我們可以在一些惡劣天氣下照?？梢酝瓿刹僮鳎驗檫@艘垃圾清掃船不僅可以通過手動方式完成清掃情況，而且也可以通過自動方式達到目的。這艘船的到來，在今后應(yīng)該會給我們帶來很多方面，我們就能引用干凈的水源，以及我們的水源得到良好的保護。一些動植物也能很好地生存下來。今后，應(yīng)該會有個翻天覆地的變化，會讓我們看不到成片成片的垃圾漂浮在湖泊以及河道的水面上。
主要參考資料
[1] 黎啟柏，肖長周;水面垃圾打撈機械手及其液壓驅(qū)動系統(tǒng);華南理工大學(xué)學(xué)報(自然科學(xué)版);1996年02期
[2]天津海河漂浮物調(diào)查
[3] 賈秀杰;多功能全自動抓取器的應(yīng)用; 新技術(shù)新工藝;1999年04期
[4] 張玉新;王帥;水面垃圾清理船的仿真設(shè)計與研究; ];機械設(shè)計與制造;2011年04期
[5]浸水裝置，水力學(xué)以及氣體力學(xué)
[6]袁勝發(fā);許德昌;譚桂斌;王柏雨;氣動式水面垃圾清理裝置的研究;液壓與氣動;2008年12期
附錄二：An Autonomous Ship for Cleaning the Garbage Floating on a Lake
Abstract—Water pollution with floating garbage is getting more and more serious in many countries. The design of an autonomous ship for cleaning the garbage floating on a lake has been proposed. The ship is powered by a solar battery. Circuit for protection of the excessive charge and discharge of the battery system has been used. Ultrasonic sensors have been equipped to detect the distance between the ship and the bank of the lake. The position and the orientation of the ship can be determined by measuring the distance between the ship and the bank at two successive time, which is used for controlling the running direction of the ship to make the ship autonomously run in an annular zone of a short distance away from the bank. The ship has also been equipped with a system to detect the occurrence of obstacles and to bypass the detected obstacles. Two screw propellers have been installed at the two sides of the ship to drive the ship, which makes the ship change its direction nimbly. A photo-resistance has been used to determine if it is in daytime or nighttime. The ship circulates the lake only one time at nighttime to save power energy. Wireless remote control is also available, which makes the ship
user friendly. Experiments have demonstrated the applicability of the design。
Keywords: autonomous; floating garbage; ultrasonic; cleaning ship; pollution
I. INTRODUCTION
Natural lakes and all kinds of artificial lakes make the living environment beautiful. However, with the increase of the activities of human being, the pollution of the floating garbage on the surface of the lake is more and more serious. Governing the pollution of the floating garbage on the surface of the lake is more and more urgent [1]. It can be seen by observation that the velocity of the water flow in the lake is very low. Sometimes it is almost zero. Most of the floating garbage distribute over an area near the bank of the lake [2]. At present, almost all these floating garbage is cleaned manually [3], which is time consuming, expensive in cost, and low in efficiency. To solve the abovementioned problem, we have designed an autonomous ship for cleaning the garbage floating on a lake. As shown in Fig.1, a model ship has been developed. Experiments have been conducted to demonstrate the applicability of the design.
II. DESIGN OF THE CLEANING SHIP
The cleaning ship is powered by solar battery, which is economic, and can save energy and protect environment. The cleaning ship determines the position and the direction of it’s own by taking the lake bank as the frame of reference. The ship runs around the lake bank by controlling itself running in a predefined distance away from the lake bank. At the
same time, it automatically cleans the floating garbage. The ship can change direction if the equipped ultrasonic sensors have detected obstacles. Circuits for recognizing the daytime and the nighttime are designed too. The ship runs only once at nighttime to save electric energy. The circulating times of cleaning floating garbage at daytime can be determined according to the practical environment. A remote control circuit is designed, which makes manual control of the ship applicable. This is useful in some special circumstances, and thus can increase the practicability of the ship. A mechanism for collecting floating garbage is designed to realize automatic collecting floating garbage.
To realize the functions mentioned above, the designed cleaning ship should be controlled by a microprocessor. It should also have power supply system, keyboard and
display, obstacles detecting system, ship position and orientation detection system, motion controlling system, circuit for recognizing daytime and nighttime, and remote
control system, as can be seen in Fig.2.
Figure 2. The structure of the cleaning ship
A. Design of the single-chip microcomputer (SCM) system
The main SCM system of the cleaning ship is made up of a SCM, a crystal oscillator, a watchdog timer. The SCM is
AT89S52, produced by Atmel Corporation. It features 8k bytes of on-chip flash memory, 256 Bytes of on-chip RAM, two 16-bit timers/counters, two external interrupt, and one
full duplex UART .The oscillating frequency of the SCM is 12 MHz. The Watchdog timer reset the computer system on power up, power failure, and other abnormity. The
Watchdog circuit is MAX813, produced by Maxim Corporation, which is dedicated to production of integrated circuits for power-detection and Watchdog timer
B. Design of the keyboard and display module
ZLG7289 has been applied in both the keyboard circuit and the display circuit in our cleaning ship, which was produced by Zhouligong Corporation situated in Guangzhou.
A ZLG7289 chip can drive 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDS, and a keyboard of up to 64 keys. It communicates with the SCM through the serial peripheral interface (SPI) [4], which takes only three I/O pins of the SCM to save its limited resources. The key pin of the ZLG7289 becomes low when a
key is pressed. The SCM identifies the number of the keystroke by SPI bus when reading the low level signal. There are eight 7-segment numeric LED displays and six keys. 7-segment numeric LED display the distance value obtained from the distance-detection system. Six function keys are used for setting the control parameters of the
cleaning ship.
C. Design of the motion control system
The motion control system controls the cleaning ship to move in a lake. Two slave systems detect the distances between the bank and the cleaning ship, and sent the distance values to the main control system through the asynchronous serial port. The main control system determines the position and orientation of the cleaning ship according to the two distance values. Ultrasonic range sensors are used to measure
the distance in the system. Ultrasonic ranging is a method that uses reflective ranging method [5]. The distances to be measured are calculated according to the time period
between the time at which the system transmits ultrasound waves and that at which the system receives the echo. Every ranging system is controlled by an independent SCM to
transmit the ultrasound and to receive its echo [6]. The dedicated integrated circuit LM1812 fulfills the task of transmitting ultrasound waves. While the task of receiving the echo is fulfilled by the infrared receiver module CX20106. When the control signal of the transmission of the ultrasound is sent, the internal timer of the SCM is being started at the same time. The integrated circuit CX20106 will send a low-level signal through which the external interrupt of the SCM is triggered to stop the timer when the echo is received. The distance between the ship and objects can be calculated from the data in the timer. The ship is equipped with two ultrasonic ranging systems. One of which is at the front of the ship, marked as “A”. Another is placed at the ship’s right side, marked as “B”.
The two sensors measure the distance between the ship and the bank of the lake once every two seconds. The position and orientation of the ship relates to the bank of the
lake are determined according to the distances at two successive times. There are several different situations as described in the following
The first situation is that the distances measured by A at both the first and the second times are over range. That is to say that the distance is more than 3 meters. And the distances measured by B are the same, about 60 centimeters, at this time, the ship is considered to be parallel to the bank of the lake, (see Fig. 3 time 2).
The second situation is that the distances measured by A at both the first and the second times are over range. Therefore, there are no obstacles in front. However, the first
distance measured by B is smaller than the second one, which suggests that the bank turns to the right, (see Fig.3 time 3).
The third situation is that the distances measured by A at both the first and the second times are over range. While the first distance measured by B is lager than the second, which suggests that the bank turns to the left, (see Fig.3 time 4). The last situation is that the distances measured by A are less than two meters while the distances measured by B are the same. In this situation, obstacles may exist in front of the ship or the bank takes a right-angle turn to the left (see Fig.3 time 5). The motors will be controlled correspondingly to make the ship move around the bank of the lake.
Figure 3. Ship motion control strategy
D. Design of the bypassing obstacles system
When moving in the lake, the cleaning ship may encounter obstacles. Therefore, it should be able to automatically bypass obstacles, and then return to its original orbit. Whether there exist obstacles or not is determined based on the data the two ultrasonic sensors measured. The preliminary decision of an obstacle or a turning of the bank in front of the ship is similar to the method for deciding the right-angle turn to the left. That is to say that the distances measured by A are two meters, and the distances measured by B are the same. In this situation, an obstacle or a turning of the bank is considered to be in the front, and therefore the ship should be controlled to make a right-angle left turn (see Fig.4 time 1). When the distances measured by A are larger than 3 meters and the distances measured by B are 60 centimeters, the ship starts to go straightly. If the ship has made a right-angle turn to the left, the distances measured by B will not change (see Fig.4 time 5).If the ship has encountered an obstacle, the distances measured by B will become bigger than the distances measured before. The reason is that obstacles are arc-shaped or rectangular-shaped. The ship will turn to right accordingly (see Fig.4 time 3). Not until that the distances measured by B are 60 centimeters, will the ship go straight. The ship will turn left at right angles after the bank of the lake is detected (see Fig.4 time 3). Finally, the ship will go back to the confined orbit as the distances measured by A are lager than 3 meters and the distances measured by B are 60 centimeters.
Figure 4. Strategy for the ship to bypass an obstacle
E. Design of the circuit for recognizing daytime/nighttime
Using a photosensitive resistance, which will have different resistance values under different light intensity, the system is able to recognize daytime and nighttime. When light is strong, its resistance value is small. On the contrary, resistance value will increase at low light. In the recognizing circuit, fixed resistors and photosensitive resistor are used to divide up the fixed voltage, and referenced voltage has been adopted. A voltage comparator is used to determine the output voltage. If the voltage divided up is smaller than the referenced voltage, the recognizing daytime and nighttime system determines it is at nighttime, otherwise it is considered at daytime. During the daytime, the frequency of the cleaning circulation can be set. While at nighttime, the cleaning ship circulates only one time.
F. Design of the motor control system
The power of the cleaning ship, including the conveyor belt of the refuse collection and transmission, and the two propellers which drive the ship and change its direction nimbly, are all powered by DC motors. The two high speed DC motors used to drive two propellers, and the motor used to drive the conveyor belt with gear case, are all controlled
by special ICs Numbered TA8050P. Five controlling scenarios are designed which include going straight, turning to the left, turning to the right, turning to the left at rightangle
and turning to the right at right-angle. The speeds of the two high-speed motors are controlled running at the same speed when the ship is going straight. The ship is turning left when the right side motor speeds up while the speed of the left side motor remains unchanged The left side motor speeds up while the speed of the right side motor keeps
unchanged will lead to the ship turning right, which can result to a larger turning radius. The ship is turning left at right angle when the left side motor stops while the right side
motor runs at the original speed. In the opposite situation, the ship is turning right at right angle.
G. Design of the remote control system
Besides the keyboard and display circuit, the remote control system is also designed to achieve manual control of the cleaning ship. Radio frequency signal, which can be
radiated around and cannot be warded off by obstacles, is used as carriers to transport the remote control message. The remote controller can control the ship in a distance of up to 500 meters. It has 8 keys, including the key to switch between the manual mode and automatic mode, the keys to control the moving directions, and the key to control the
motor that drives the conveyor belt.
H. Design of the power supply systems
The control system needs a 12-volt power supply, which is used for powering the ultrasonic transmitter and the DC motors. It also needs a 5-volt power supply used for
powering the single-chip control system. The power comes from a solar battery of 15Watts rated output, which is used to charge a 12V/7AH maintenance-free lead acid battery. The latter is then used to power the system. During charge process, the battery voltage is monitored by the power system to avoid overcharge and over-discharge. The 5-volt power supply for the SCM is stabilized by a three-terminal voltage regulator. In order to avoid the motor starting/stopping operations influencing the control circuit, a DC-DC power conversion circuit is designed for power supply isolation.
I. Design of programs
According to the process of the work of the cleaning ship, the programs of the main SCM system and distance measurement systems are designed in a modular structure. The programs of the main SCM system consist of the following modules: the program for managing the power system, the program for the remote control, the program for communicating with slave distance measurement systems, the program for controlling the moving directions, and the program for controlling the motors. The flow chart of the main
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