【正文】 ved with System B.Fig. 8. Experimental setup for the measurement of the relation of the maximum measurabledistance to the width of a reflected object.Fig. 9. The change of the maximum measurable distance to the width of a reflected object.Fig. 10. The directivity of ultrasonic sensor for the obstacle detection. The obstacles cannot bedetected by the narrow directivity. In many cases, ultrasonic sensors are attached to a horn to increase the intensity of waves on the transducer lineofsight, so the directivity bees narrow. A narrow directivity is better in order to know the exact direction which obstacles exist. However, only obstacles which face perpendicularly the transducers lineofsight can be detected with a narrow directivity. It is important for mobile robots’ obstacle detection to know whether obstacles exist or not, and how far there are. So, a wide directivity is also required for obstacle detection as shown in Fig. 10. With System B, more sensitivity can be obtained without a horn than with System A. Therefore the directivity of System B can be wide as is verified in next section, and it is more available for obstacle detection.IV. Sonar Map UnderstandingWe investigate environment map making using two ultrasonic ranging systems. The method of making maps was for the range data to be placed along the transducer orientation at a measured range. There were flat walls and rightangle corners (convex and concave). System A used a horn to increase its intensity. Each system is mounted on our mobile robot “YAMABICO”[5] (Fig. 11), and the orientation of the system was changed by rotating the robot. The experimental environment is shown in Fig. 12, the experimental results of System A and B are shown in Fig. 13 and 14, respectively. The sensors were put on the origin (0, 0).Fig. 11. System B mounted on our mobile robot “YAMABICO”. The right side is a transmit and receive circuit for one direction (70mm 163。Ⅴ 結(jié)論從上述結(jié)果可以得到以下結(jié)論：●障礙物檢測的性能隨著不同傳感器系統(tǒng)變化。作為一個(gè)結(jié)果，看來這個(gè)系統(tǒng)有一個(gè)狹窄的方向性。實(shí)驗(yàn)環(huán)境如圖12，系統(tǒng)A和B的實(shí)驗(yàn)結(jié)果分別顯示在圖13和14中。了解障礙物存在與否及有多遠(yuǎn)對于移動(dòng)機(jī)器人的障礙物檢測很重要。在圖9，系統(tǒng)A的結(jié)果在圖形下方，系統(tǒng)B在圖形上方。圖7顯示了B系統(tǒng)中的放大接收信號和閾值水平。為了以一個(gè)簡單的電路解決這個(gè)問題，而不是放大因素，閾值水平應(yīng)隨時(shí)間變化。其次，通過利用高電壓超聲波脈沖發(fā)射，發(fā)射波上升時(shí)間縮短了。然而，它使方向性狹窄。但是，這種系統(tǒng)存在一些問題。隨著一個(gè)超聲波的衰減和傳播，反射回波幅度越遠(yuǎn)，對象就較?。ㄉ踔羴碜酝粚ο螅Ｆ渲衏是超聲波在空氣中的傳播速度，t是往返飛行時(shí)間（圖1）。綜上所述，系統(tǒng)開發(fā)是完全可行的。因此，在技術(shù)上，此課題是完全可行的。(2) 諧振帶寬、波束角可以通過制作工藝控制得很窄, 有利于抗聲波干擾設(shè)計(jì)。另外，在實(shí)際駕駛環(huán)境中，倒車的環(huán)境不如實(shí)驗(yàn)設(shè)計(jì)的理想，如車后的物質(zhì)會影響超聲波判斷確切距離。淮海工學(xué)院畢業(yè)設(shè)計(jì)開題報(bào)告，可能遇到的困難，提出解決問題的方法和措施此系統(tǒng)是在單片機(jī)的控制下, 利用超聲波測距原理, 測量汽車在倒車過程中與障礙物之間的距離。在整個(gè)停車過程中，當(dāng)駕駛員切換到倒檔后，導(dǎo)航系統(tǒng)會由始至終地監(jiān)測汽車的位置和角度。但是此類產(chǎn)品在輔助倒車方面也只能提供車后的視頻圖像信息，對距離信息仍然無法感知。汽車已經(jīng)成為很多人日常生活中必不可少的一部分，我國汽車的數(shù)量逐年增加,但是隨著汽車數(shù)量和駕駛員的逐漸增加也引發(fā)了一系列問題。 汽車輔助倒車系統(tǒng)國內(nèi)外現(xiàn)狀目前在國內(nèi)，汽車倒車輔助系統(tǒng)大多數(shù)仍停留在語音報(bào)警或圖像顯示的階段上，還沒有智能可視倒車輔助系統(tǒng)出現(xiàn)。梅賽德斯車廠已經(jīng)在使用雷達(dá)探測技術(shù)來幫助駕駛者更快更安全地停車。從這里開始，停車過程便由配備了超聲波雷達(dá)和攝像頭的停車導(dǎo)航系統(tǒng)全權(quán)接手。這樣就可以大大提高倒車和泊車的效率和安全性。通過上網(wǎng)查詢資料及學(xué)習(xí)相關(guān)的書籍，請教指導(dǎo)教師等有效途徑來進(jìn)行硬件設(shè)計(jì)和軟件設(shè)計(jì)。當(dāng)它的兩級外加脈沖信號, 其頻率等于壓電晶片的固有振蕩頻率時(shí), 壓電晶片將會發(fā)生振,動(dòng) 并帶動(dòng)共振板振動(dòng), 便產(chǎn)生超聲波。利用超聲波制作汽車防撞雷達(dá)可以幫助駕駛員及時(shí)了解車周圍阻礙情況, 防止汽車在轉(zhuǎn)彎、倒車等情況下撞傷、劃傷。至于射程傳感器，可以測量與物體間的距離，超聲波傳感器普遍用于移動(dòng)機(jī)器人中，因?yàn)樗w積小，價(jià)格低廉，更易于距離的計(jì)算。其障礙物檢測的可用性在第三節(jié)驗(yàn)證，聲納地圖制作使用在第四部分。一個(gè)范圍值的計(jì)算方式是使用擴(kuò)增回聲飛行時(shí)間和閾值法水平。當(dāng)級別設(shè)置較高時(shí)，不可能檢測遠(yuǎn)距離物體。這種方法有以下好處。寶麗來超聲波測距定位傳感器解決了隨時(shí)間變化的放大系數(shù)這個(gè)問題。此外，由于超聲波緩慢上升造成測量誤差。傳統(tǒng)的系統(tǒng)連接到角，以增加回波強(qiáng)度。在許多情況下，超聲波傳感器連接到一個(gè)喇叭，以增加換能器視線內(nèi)波的強(qiáng)度，所以方向性變窄。其有圍墻和直角彎道（凸，凹）。圖12實(shí)驗(yàn)環(huán)境。從這個(gè)圖形可以看到，該系統(tǒng)B指向性寬，由于距離數(shù)據(jù)躺在一個(gè)傳感器與圓的弧線上且其中心在傳感器上。不幸的是，幾乎大多數(shù)的電流傳感器并沒有那么聰明，而且能力是有限的。 The shape of the resultant sonar map changes drastically according to the characteristics of the sensor such as sensitivity, directivity and so on.178。圖13 系統(tǒng)A 的合成聲納地圖 圖14 系統(tǒng)B 的合成聲納地圖Obstacle Detectability of Ultrasonic Ranging Systemand Sonar Map UnderstandingAbstractInformation obtained by the ultrasonic sensor is influenced by the characteristics of the sensing system such as sensitivity, directivity and so on. In order to investigate its influence, we constructed two ultrasonic ranging