【正文】 持結(jié)構(gòu)主要由以下 分系統(tǒng) 夠成： ? Translation stage 移動臺 ? Rotation stage 旋轉(zhuǎn)臂 ? Sustaining arm 支撐臂 ? Protective box保護箱 The optical head consists of a long working distance objective with the following characteristics: 光學探頭具有長工作 距離 物鏡，其特性如下 : Parameter 參數(shù) Unit 單位 Value 數(shù)值 Field of view 視場 mm Resolution 分辨率 mm Depth of Field 景深 mm Working Distance 工作距離 mm 175 北京和德宇航技術(shù)有限公司 China Head Aerospace Technology Co. Page： 5/31 The measurement system allows the inspection of the acceleration grid (measurement of the hole diameter variation across a diameter of the grid). 系統(tǒng)也可進行加速極檢測（通過一個網(wǎng)格的直徑測量孔徑的差異）。C 2) 150 800 176。C * Interface: Fast Ether (realtime 50Hz max) * 4 I/O digital ports: digital inputs (trigger), digital output (alarm) * Power Input : 10…36Vcc, 5VA * Weight : about kg * Dimensions (mm) : 85 x 175 x 107 mm * Protection : IP54 以下性能較高的相機作為可選項目提供： ? 傳感器：微測輻射熱 非冷卻 382x288pixels ? 光譜范圍： 8…14 微米 ? 測量范圍： 1) 0 200 176。C ? 接口：快速以太網(wǎng)（最大值實時 50Hz） ? 種 I/O 數(shù)字分類：數(shù)字輸入（觸發(fā)），數(shù)字輸出（警報） ? 電源輸入： 10…36Vcc, 5VA ? 重量：約 ? 外形尺寸（ mm）： 85 x 175 x 107 mm ? 保護： IP54 In Figure 3 a scheme of the infraredcamera system is displayed. The camera is contained in a sealed box, where atmospheric pressure is maintained (since the camera cannot operate in vacuum). 圖 3 為紅外相機系統(tǒng)示意圖，相機處于密封箱內(nèi)，可保持大氣壓強（相機不能再真空環(huán)境工作）。 R02 – Primary erosion measurement 初始腐蝕測量 The primary erosion measurement will be concerned with the hole erosion on the external grid (a dimension change of few percentage points should be considered as target for the minimum detectable erosion). 初始腐蝕測量主要涉及的是外部柵極的孔腐蝕（最小可測腐蝕應考慮到幾個百分點的外形變化）。C； 濕度： 1060 %； 可用電源： 220V AC R08 – Vacuum chamber requirements 真空罐要求 The EMS should be used in a new vacuum chamber, 2 m in diameter for about 5 m in length, described in the scheme of Figure 5 and Figure 6. 真空罐直徑 2m，長約 5m，見圖 5， 6。 ? 程序高度自動化。 與 510 所協(xié)商確認一組基本的失效模式，如可能，將其正確的處理方式和警報嵌入控制軟件中。 4 Technical Implementation 技術(shù)實現(xiàn) In order to positively answer to all the previous requirements by LIP, the following technical implementation will be used. Additional interaction with the Customer might be required. Important elements are presented inside boxes within the text. 以下的技術(shù)實現(xiàn)將對 510 所上述的所有要求做出正面解答。 4） 建議在所分析區(qū)域確認幾個參考點，以抵消因環(huán)境條件而造成的圖像采集位置的細微變化。 ? 缺少可測量 亞毫米級 的窄光線。 Secondary grid erosion measurement (option) 二次網(wǎng)格腐蝕測量（可選） An additional feature that could be implemented in Alta present system is the hole erosion measurement of the internal grid. If the grid position is patible with the camera focus regulation it should be possible to obtain focused images of the back grid holes and therefore retrieve their erosion. Of course in this case only hole diameter could be measured. Alta 現(xiàn)有系統(tǒng)可執(zhí)行的附加功能有 內(nèi)部 網(wǎng)格孔腐蝕的測量。 注釋： 510 所應盡快向 Alta 提供推進器機械接口和其它放置在真空罐內(nèi)部部件的詳細信息，以正確設(shè)計系統(tǒng)，避免在 運動過程中與真空罐內(nèi)的結(jié)構(gòu)碰撞，并將相機正確安放在可精確測量的位置。 Figure 12: Example of mercial feedthroughs to insert in a flange circular hole 圖 12 商用饋入裝置插入凸緣圓孔實例 Preliminary Calibration procedure 初步校準程序 The preliminary calibration will be based on the following setup and procedure: ? The EMS will be mounted inside the vacuum chamber with the thruster (with known dimensions taken by direct measuring before installing it) already installed. ? A set of pictures with all the cameras in known positions will be taken. It is suggested to take more pictures than the ones that will be used in the actual test to have better results. ? The picture procedure will be repeated when the system has reached the primary vacuum level (a first level of structure deformation will be caused by the pressure decrease). ? The picture procedure will be repeated again if cryogenic cooling is used (a second level of structure deformation will be caused by temperature change inside the vacuum vessel). ? The procedure will be repeated with inversed steps when the chamber is brought back to atmospheric pressure. The aim of this secondary calibration is to verify the relative positioning of the system after long use in vacuum. 根據(jù)以下安裝程序進行初步校準： ? EMS 同已安裝的推進器一起固定于真空罐內(nèi)部（安裝前直接測量已知外形尺寸）。 3） 每次校準約最多持續(xù) 1520分鐘。 ? 當真空罐恢復大氣壓強時，程序逆轉(zhuǎn)，重復拍攝。結(jié)構(gòu)必須足夠的強度確保 TMS 的正確定位。整體結(jié)構(gòu)外殼，含在安全區(qū)定位： ? 寬 750mm（當處于安全停放位置并采用最長水平參考線時的最大值 ） ? 高 550mm ? 深 600mm（當處于測量位置時的最大值） 注釋： 需注意的是在 可移動的機械臂上一次只能安裝 2個相機 ，如果 510所安裝 3個相機（兩個影像，一個 IR 熱譜）則其中一個需固定在真空罐的合適位置，如圖 8 所示。 An alternative interesting feature could be the use of stereoscopy, . to take two entire pictures with a slightly different exposure angle (or two different cameras) and then reconstruct by software the whole image. Also in this case a dedicated feasibility campaign is underway。 Pit/groove erosion 坑 /槽 腐 蝕 Pit/groove erosion is a phenomenon typical of GIE, that is typically detected and measured by microscope after the test end. As shown in Figure 7, it is an erosion pattern of the material surrounding the external grid holes that typically has a depth in the submillimeter range. At present stage Alta’s EMS has not been tested and used to measure such kind of erosion. A dedicated feasibility study is underway, with the main difficulties being: the reflective properties of the metallic grid that sometimes make it difficult to clearly detect the pit/groove profile. line to be able to measure something in the sub millimeter range. The present laser beams are too wide, so other possibilities are 北京和德宇航技術(shù)有限公司 China Head Aerospace Technology Co. Page： 17/31 un