畢 業(yè) 設(shè) 計(jì) 論 文 開(kāi) 題 報(bào) 告 設(shè)計(jì) 論文 題目 三自由度 Delta 并聯(lián)機(jī)器人的設(shè)計(jì)與仿真 學(xué)生姓名 專 業(yè) 所在學(xué)院 指導(dǎo)教師 職 稱 年 月 日 開(kāi)題報(bào)告填寫要求 1 開(kāi)題報(bào)告 含 文獻(xiàn)綜述 作為畢業(yè)設(shè)計(jì) 論 文 答辯委員會(huì)對(duì)學(xué)生答辯資格審查的依據(jù)材料之一 此 報(bào)告應(yīng)在指導(dǎo)教師指導(dǎo)下 由學(xué)生在畢業(yè)設(shè)計(jì) 論文 工 作前期內(nèi)完成 經(jīng)指導(dǎo)教師簽署意見(jiàn)及所在專業(yè)審查后生 效 2 開(kāi)題報(bào)告內(nèi)容必須用黑墨水筆工整書寫或按教務(wù) 處統(tǒng)一設(shè)計(jì)的電子文檔標(biāo)準(zhǔn)格式打印 禁止打印在其它紙 上后剪貼 完成后應(yīng)及時(shí)交給指導(dǎo)教師簽署意見(jiàn) 3 文獻(xiàn)綜述 應(yīng)按論文的框架成文 并直接書寫 或打印 在本開(kāi)題報(bào)告第一欄目?jī)?nèi) 學(xué)生寫文獻(xiàn)綜述的 參考文獻(xiàn)應(yīng)不少于 15 篇 不包括辭典 手冊(cè) 4 有關(guān)年月日等日期的填寫 應(yīng)當(dāng)按照國(guó)標(biāo) GB T 7408 94 數(shù)據(jù)元和交換格式 信息交換 日期和時(shí)間表 示法 規(guī)定的要求 一律用阿拉伯?dāng)?shù)字書寫 如 2004 年 4 月 26 日 或 2004 04 26 5 開(kāi)題報(bào)告 文獻(xiàn)綜述 字體請(qǐng)按宋體 小四號(hào)書 寫 行間距 1 5 倍 畢 業(yè) 設(shè) 計(jì) 論文 開(kāi) 題 報(bào) 告 1 結(jié)合畢業(yè)設(shè)計(jì) 論文 課題情況 根據(jù)所查閱的文獻(xiàn)資料 每人撰寫不少于 1000 字左右的文獻(xiàn)綜述 自從 1961 年美國(guó) Unimation 公司推出第一臺(tái)工業(yè)機(jī)器人以來(lái) 機(jī)器人得到了十 分迅速的發(fā)展 如今機(jī)器人已經(jīng)廣泛應(yīng)用于工業(yè)生產(chǎn)中 如噴氣 焊接 搬運(yùn) 裝配等工作 在汽車工業(yè) 電子工業(yè) 核工業(yè) 服務(wù)業(yè)和醫(yī)療衛(wèi)生等許多方面 都有應(yīng)用 現(xiàn)在所說(shuō)的機(jī)器人多指串聯(lián)機(jī)器人 1965 年 英國(guó)高級(jí)工程師 Stewart 首先提出了一種 6 自由度的并聯(lián)機(jī)構(gòu)作為飛行模擬器用于訓(xùn)練飛行員 到 1978 年 澳大利亞的 Hunt 教授指出這種機(jī)構(gòu)更接近于人體的結(jié)構(gòu) 可以將 此平臺(tái)作為機(jī)器人機(jī)構(gòu) 80 年代中期 國(guó)際上研究并聯(lián)機(jī)器人的學(xué)者還寥寥無(wú) 幾 出的成果也不多 到 80 年代末期特別是 90 年代以來(lái) 并聯(lián)機(jī)器人才被廣 為關(guān)注 并成為新的熱點(diǎn) 許多大型會(huì)議都設(shè)有專題進(jìn)行討論 1985 年 Clavel 提出了一種成為 Delta 的三維移動(dòng)機(jī)構(gòu) Delta 機(jī)器人是最經(jīng)典的空間 三自由度移動(dòng)的并聯(lián)機(jī)構(gòu) 大多數(shù)空間三自由度并聯(lián)機(jī)構(gòu)都是從 Delta 機(jī)構(gòu)衍 生的 Delta 機(jī)器人是一種具有 3 個(gè)平動(dòng)自由度的告訴并聯(lián)機(jī)器人 也是目前 商業(yè)應(yīng)用最成功的并聯(lián)機(jī)器人之一 目前 國(guó)內(nèi)外對(duì)于并聯(lián)機(jī)器人的研究主要集中于機(jī)構(gòu)學(xué) 運(yùn)動(dòng)學(xué) 動(dòng)力學(xué)和控 制策略等幾個(gè)領(lǐng)域 其中機(jī)構(gòu)學(xué)和運(yùn)動(dòng)學(xué)分析主要研究并聯(lián)機(jī)器人的運(yùn)動(dòng)學(xué) 奇異形位 工作空間和靈巧度分析等方面 這些研究是實(shí)現(xiàn)并聯(lián)機(jī)器人控制和 應(yīng)用的基礎(chǔ) 動(dòng)力學(xué)和控制策略的研究主要是對(duì)并聯(lián)機(jī)器人進(jìn)行動(dòng)力學(xué)分析和 建模 研究各種可能的控制算法 對(duì)并聯(lián)機(jī)器人實(shí)時(shí)控制 以達(dá)到預(yù)期的控制 效果 隨著微電子和計(jì)算機(jī)技術(shù)的發(fā)展 并聯(lián)機(jī)器人得到了越來(lái)越廣泛的應(yīng)用 工業(yè) 上 并聯(lián)機(jī)器人可以用在汽車總裝線上安裝輪胎 汽車發(fā)動(dòng)機(jī) 還可以用作飛 船對(duì)接器 潛艇救援中的對(duì)接器 飛行模擬器 空間飛行器對(duì)接機(jī)構(gòu)及其地面 試驗(yàn)設(shè)備 天文望遠(yuǎn)鏡跟蹤元位系統(tǒng)等 其中 Delta 機(jī)器人被廣泛應(yīng)用于食品 與藥品的包裝與機(jī)械自動(dòng)生產(chǎn)線上 對(duì)于困難的地下工程 也可以利用并聯(lián)機(jī) 構(gòu) 并聯(lián)機(jī)器人的一個(gè)重要應(yīng)用就是被稱為 21 世紀(jì)的機(jī)床 的虛擬軸機(jī)床 并聯(lián)機(jī)床的中心結(jié)構(gòu)簡(jiǎn)單 傳動(dòng)鏈極短 剛度大 質(zhì)量輕 切削效率高 成本 低 很容易實(shí)現(xiàn) 6 軸聯(lián)動(dòng) 因而可以加工非常復(fù)雜的三維曲面 1994 年美國(guó)芝 加哥 IMTS 博覽會(huì)上 GIDDING LEWIS 公司推出了新開(kāi)發(fā)的并聯(lián)式 VARJAX 虛擬 軸機(jī)床 硬氣廣泛關(guān)注 并聯(lián)機(jī)器人的另一個(gè)重要的應(yīng)用方面是作為微動(dòng)機(jī)構(gòu)或微型機(jī)構(gòu) 這種機(jī)構(gòu)充 分發(fā)揮了并聯(lián)機(jī)構(gòu)空間不大 精度和分辨率高的特點(diǎn) 在三維空間內(nèi)微小移動(dòng) 在 2 20 微米之間 如在眼科手術(shù) 微細(xì)外科手術(shù)中的細(xì)胞操作 心臟冠狀動(dòng)脈 移植等中都得到了很好的應(yīng)用 參考文獻(xiàn) 1 蔡自興 機(jī)器人學(xué)基礎(chǔ) M 北京 機(jī)械工業(yè)出版社 2009 2 叢爽 尚偉偉 并聯(lián)機(jī)器人 建模 控制優(yōu)化與應(yīng)用 M 北京 電子工業(yè) 出版社 2010 3 張利敏 梅江平 趙學(xué)滿 等 一種二平動(dòng)自由度并聯(lián)機(jī)械手動(dòng)力尺度綜合 J 天津大學(xué)學(xué)報(bào) 2010 43 8 661 666 4 Bouri M Clavel R The linear Delta Developments and applications C The 41st International Symposium on Robotics Frankfurt Germany VDE 2010 1198 1205 5 Milutinovic D Slavkovic N Kokotovic B et al Kinematic modeling of reconfigurable parallel robots based on Delta concept J Journal of Production Engineering 2012 15 2 71 74 6 Rey L Clavel R The Delta parallel robot M Parallel Kinematic Machines London UK Springer 1999 401 417 7 Pierrot F Dauchez P Fournier A Fast parallel robots J Journal of Robotic Systems 1991 8 6 829 840 8 徐龍祥 歐陽(yáng)祖行 機(jī)械設(shè)計(jì) M 第二版 北京 航空工業(yè)出版社 1999 9 李柱 互換性與技術(shù)測(cè)量 M 北京 高等教育出版社 2004 10 哈爾濱工業(yè)大學(xué)理論力學(xué)教研室 理論力學(xué) M 北京 高等教育出版社 2009 11 王全景 張慶余 48 小時(shí)精通 CREO PARAMETRIC 3 0 中文版零組件設(shè)計(jì)技巧 M 北京 電子工業(yè)出版 2013 12 范欽珊 材料力學(xué) M 北京 清華大學(xué)出版社 2008 13 Kosinska A Galicki M Kedzior K Designing and optimization of parameters of Delta 4 parallel manipulator for a given workspace J Journal of Robotic Systems 2003 20 9 539 548 14 楊斌久 蔡光起 羅繼曼 等 少自由度并聯(lián)機(jī)器人的研究現(xiàn)狀 J 機(jī)床 與液壓 2006 34 5 202 205 15 黃真 孔令富 方躍法 并聯(lián)機(jī)器人機(jī)構(gòu)學(xué)理論及控制 M 北京 機(jī)械工 業(yè)出版社 1997 16 付萌 少自由度并聯(lián)機(jī)構(gòu)尺度參數(shù)的多目標(biāo)優(yōu)化研究 D 電子科技大學(xué) 2013 畢 業(yè) 設(shè) 計(jì) 論文 開(kāi) 題 報(bào) 告 2 本課題要研究或解決的問(wèn)題和擬采用的研究手段 途徑 主要研究?jī)?nèi)容 1 基座的設(shè)計(jì) 2 末端執(zhí)行器的設(shè)計(jì) 3 臂桿的設(shè)計(jì) 4 電動(dòng)機(jī)的選型 5 傳動(dòng)鏈的選擇 6 Delta 型并聯(lián)機(jī)器人的布置形式及基本參數(shù)的確定 擬采用的研究手段 設(shè)計(jì)一種直線型 Delta 并聯(lián)機(jī)器人 動(dòng)平臺(tái)與靜平臺(tái)之間通過(guò)三條支鏈連 接 通過(guò)安裝在固定框架上的三個(gè)直流電機(jī)結(jié)合滾珠絲杠副產(chǎn)生的直線運(yùn) 動(dòng) 使動(dòng)平臺(tái)具有一個(gè)平動(dòng)自由度和兩個(gè)轉(zhuǎn)動(dòng)自由度 每個(gè)電機(jī)安裝有編 碼器用于檢測(cè)其轉(zhuǎn)角 通過(guò)機(jī)構(gòu)運(yùn)動(dòng)學(xué)建?？捎?jì)算出動(dòng)平臺(tái)的位姿信息 并用于實(shí)現(xiàn)對(duì)機(jī)器人的控制 在完成設(shè)計(jì)工作的同時(shí) 針對(duì) Delta 型并聯(lián) 機(jī)器人的設(shè)計(jì)進(jìn)行分析研究 以便確定其合理的結(jié)構(gòu)和性能參數(shù) 畢 業(yè) 設(shè) 計(jì) 論文 開(kāi) 題 報(bào) 告 指導(dǎo)教師意見(jiàn) 1 對(duì) 文獻(xiàn)綜述 的評(píng)語(yǔ) 對(duì)并聯(lián)機(jī)器人應(yīng)用于工業(yè)領(lǐng)域的研究現(xiàn)狀 發(fā)展趨勢(shì) 設(shè)計(jì)原則 存在問(wèn)題 未來(lái)發(fā)展方向作了較豐富的綜述 內(nèi)容充實(shí) 條理清晰 表述清楚 2 對(duì)本課題的深度 廣度及工作量的意見(jiàn)和對(duì)設(shè)計(jì) 論文 結(jié)果的 預(yù)測(cè) 本課題涉及一種三自由度 Delta 并聯(lián)機(jī)器人設(shè)計(jì) 具有非常現(xiàn)實(shí)的應(yīng)用背景 本設(shè)計(jì)主要包括三自由度 Delta 并聯(lián)機(jī)器人結(jié)構(gòu)設(shè)計(jì) 要求設(shè)計(jì)者不僅掌握較 扎實(shí)的機(jī)電一體化設(shè)計(jì)能力 還應(yīng)掌握較深的機(jī)器人專業(yè)理論基礎(chǔ) 因此本課 題較難 工作量較大 本設(shè)計(jì)的成果應(yīng)包括三自由度 Delta 并聯(lián)機(jī)器人結(jié)構(gòu)模 型 裝配圖 零件圖 運(yùn)動(dòng)仿真等內(nèi)容 3 是否同意開(kāi)題 同意 不同意 指導(dǎo)教師 2016 年 03 月 17 日 所在專業(yè)審查意見(jiàn) 同意 負(fù)責(zé)人 2016 年 03 月 17 日 畢 業(yè) 設(shè) 計(jì) 論 文 任 務(wù) 書 設(shè)計(jì) 論文 題目 三自由度 Delta 并聯(lián)機(jī)器人的設(shè)計(jì)與仿真 學(xué)生姓名 專 業(yè) 所在學(xué)院 指導(dǎo)教師 職 稱 發(fā)任務(wù)書日期 年月日 任務(wù)書填寫要求 1 畢業(yè)設(shè)計(jì) 論文 任務(wù)書由指導(dǎo)教師根據(jù)各課題的具 體情況填寫 經(jīng)學(xué)生所在專業(yè)的負(fù)責(zé)人審查 系 院 領(lǐng)導(dǎo)簽 字后生效 此任務(wù)書應(yīng)在畢業(yè)設(shè)計(jì) 論文 開(kāi)始前一周內(nèi)填好 并發(fā)給學(xué)生 2 任務(wù)書內(nèi)容必須用黑墨水筆工整書寫 不得涂改或潦 草書寫 或者按教務(wù)處統(tǒng)一設(shè)計(jì)的電子文檔標(biāo)準(zhǔn)格式 可從教 務(wù)處網(wǎng)頁(yè)上下載 打印 要求正文小 4 號(hào)宋體 1 5 倍行距 禁止打印在其它紙上剪貼 3 任務(wù)書內(nèi)填寫的內(nèi)容 必須和學(xué)生畢業(yè)設(shè)計(jì) 論文 完成的情況相一致 若有變更 應(yīng)當(dāng)經(jīng)過(guò)所在專業(yè)及系 院 主管領(lǐng)導(dǎo)審批后方可重新填寫 4 任務(wù)書內(nèi)有關(guān) 學(xué)院 專業(yè) 等名稱的填寫 應(yīng) 寫中文全稱 不能寫數(shù)字代碼 學(xué)生的 學(xué)號(hào) 要寫全號(hào) 不 能只寫最后 2 位或 1 位數(shù)字 5 任務(wù)書內(nèi) 主要參考文獻(xiàn) 的填寫 應(yīng)按照 金陵科 技學(xué)院本科畢業(yè)設(shè)計(jì) 論文 撰寫規(guī)范 的要求書寫 6 有關(guān)年月日等日期的填寫 應(yīng)當(dāng)按照國(guó)標(biāo) GB T 7408 94 數(shù)據(jù)元和交換格式 信息交換 日期和時(shí)間表示法 規(guī)定的要求 一律用阿拉伯?dāng)?shù)字書寫 如 2002 年 4 月 2 日 或 2002 04 02 畢 業(yè) 設(shè) 計(jì) 論 文 任 務(wù) 書 1 本畢業(yè)設(shè)計(jì) 論文 課題應(yīng)達(dá)到的目的 本畢業(yè)設(shè)計(jì)課題的主要目的是培養(yǎng)學(xué)生綜合運(yùn)用所學(xué)的基礎(chǔ)理論 專業(yè)知識(shí)和 專業(yè)基本技能分析和解決實(shí)際問(wèn)題 訓(xùn)練初步工程設(shè)計(jì)的能力 根據(jù)機(jī)械設(shè)計(jì)制 造及其自動(dòng)化專業(yè)的特點(diǎn) 著重培養(yǎng)以下幾方面能力 1 調(diào)查研究 中外文獻(xiàn) 檢索 閱讀與翻譯的能力 2 綜合運(yùn)用基礎(chǔ)理論 專業(yè)理論和知識(shí)分析解決實(shí) 際問(wèn)題的能力 3 查閱和使用專業(yè)設(shè)計(jì)手冊(cè)的能力 4 設(shè)計(jì) 計(jì)算與繪圖的 能力 包括使用計(jì)算機(jī)進(jìn)行繪圖的能力 5 撰寫設(shè)計(jì)說(shuō)明書 論文 的能力 2 本畢業(yè)設(shè)計(jì) 論文 課題任務(wù)的內(nèi)容和要求 包括原始數(shù)據(jù) 技術(shù) 要求 工作要求等 一 課題任務(wù)內(nèi)容 設(shè)計(jì)一種直線型 Delta 并聯(lián)機(jī)器人 動(dòng)平臺(tái)與靜平臺(tái)之間 通過(guò)三條支鏈連接 通過(guò)安裝在固定框架上的三個(gè)直流電機(jī)結(jié)合滾珠絲杠副產(chǎn)生 的直線運(yùn)動(dòng) 使動(dòng)平臺(tái)具有一個(gè)平動(dòng)自由度和兩個(gè)轉(zhuǎn)動(dòng)自由度 每個(gè)電機(jī)安裝有 編碼器用于檢測(cè)其轉(zhuǎn)角 通過(guò)機(jī)構(gòu)運(yùn)動(dòng)學(xué)建?？捎?jì)算出動(dòng)平臺(tái)的位姿信息 并用 于實(shí)現(xiàn)對(duì)機(jī)器人的控制 二 設(shè)計(jì)要求 1 外形尺寸 600 x600 x800 2 豎直方向 平移范圍 100mm 水平方向轉(zhuǎn)動(dòng)范圍 15 3 動(dòng)平臺(tái)最大承載 5kg 畢 業(yè) 設(shè) 計(jì) 論 文 任 務(wù) 書 3 對(duì)本畢業(yè)設(shè)計(jì) 論文 課題成果的要求 包括圖表 實(shí)物等硬件要 求 1 外文專業(yè)文獻(xiàn)翻譯 原文和譯文 譯文 3000 漢字以上 2 畢業(yè)設(shè)計(jì)開(kāi)題報(bào)告 一份 3 編寫設(shè)計(jì)說(shuō)明書一份 4 完整的設(shè)計(jì)圖紙一套 運(yùn)動(dòng)仿真結(jié)果數(shù)據(jù)以及 動(dòng)畫一套 4 主要參考文獻(xiàn) 1 蔡自興 機(jī)器人學(xué)基礎(chǔ) M 北京 機(jī)械工業(yè)出版社 2009 2 叢爽 尚偉 偉 并聯(lián)機(jī)器人 建模 控制優(yōu)化與應(yīng)用 M 北京 電子工業(yè)出版社 2010 3 張利敏 梅江平 趙學(xué)滿 等 一種二平動(dòng)自由度并聯(lián)機(jī)械手動(dòng)力尺度綜合 J 天津大學(xué)學(xué)報(bào) 2010 43 8 661 666 4 Bouri M Clavel R The linear Delta Developments and applications C The 41st International Symposium on Robotics Frankfurt Germany VDE 2010 1198 1205 5 Milutinovic D Slavkovic N Kokotovic B et al Kinematic modeling of reconfigurable parallel robots based on Delta concept J Journal of Production Engineering 2012 15 2 71 74 6 Rey L Clavel R The Delta parallel robot M Parallel Kinematic Machines London UK Springer 1999 401 417 7 Pierrot F Dauchez P Fournier A Fast parallel robots J Journal of Robotic Systems 1991 8 6 829 840 8 徐龍祥 歐陽(yáng)祖行 機(jī)械設(shè)計(jì) M 第二版 北京 航空工業(yè)出版社 1999 9 李柱 互換性與技術(shù)測(cè)量 M 北京 高等教育出版社 2004 10 哈爾濱工業(yè) 大學(xué)理論力學(xué)教研室 理論力學(xué) M 北京 高等教育出版社 2009 11 王全景 張 慶余 48 小時(shí)精通 CREO PARAMETRIC 3 0 中文版零組件設(shè)計(jì)技巧 M 北京 電子工 業(yè)出版 2013 12 范欽珊 材料力學(xué) M 北京 清華大學(xué)出版社 2008 13 Kosinska A Galicki M Kedzior K Designing and optimization of parameters of Delta 4 parallel manipulator for a given workspace J Journal of Robotic Systems 2003 20 9 539 548 14 楊斌久 蔡光起 羅繼曼 等 少自由度并聯(lián)機(jī)器人的研究現(xiàn)狀 J 機(jī)床與液壓 2006 34 5 202 205 15 黃真 孔令富 方躍法 并聯(lián)機(jī)器人機(jī)構(gòu)學(xué)理論及控制 M 北京 機(jī)械工業(yè)出版社 1997 16 付萌 少自由度并聯(lián)機(jī)構(gòu)尺度參數(shù)的多目標(biāo)優(yōu)化研 究 D 電子科技大學(xué) 2013 畢 業(yè) 設(shè) 計(jì) 論 文 任 務(wù) 書 5 本畢業(yè)設(shè)計(jì) 論文 課題工作進(jìn)度計(jì)劃 15 11 20 15 12 20 學(xué)生明確選題 15 12 20 16 01 15 學(xué)生完成開(kāi)題 報(bào)告 16 01 15 16 03 18 學(xué)生完成設(shè)計(jì)草圖階段 明確設(shè)計(jì)方案 16 03 18 16 04 08 學(xué)生完善設(shè)計(jì)正稿 撰寫畢業(yè)設(shè)計(jì)論文初稿 16 04 08 16 04 30 學(xué)生畢業(yè)設(shè)計(jì)完成階段 提交畢業(yè)論文正稿 完成期 中檢查 16 05 01 16 05 10 學(xué)生提交畢業(yè)設(shè)計(jì)論文 布置畢業(yè)設(shè)計(jì)展 16 05 10 16 05 15 布展 畢業(yè)答辯準(zhǔn)備 所在專業(yè)審查意見(jiàn) 同意 負(fù)責(zé)人 2016 年 1 月 18 日 畢 業(yè) 設(shè) 計(jì) 論 文 外 文 參 考 資 料 及 譯 文 譯文題目 由表面應(yīng)力引起的納米多孔金 懸臂梁的宏觀彎曲 學(xué)生姓名 專 業(yè) 所在學(xué)院 指導(dǎo)教師 職 稱 Surface Stress Induce d Macros copic Bendi ng of Nano porou s Gold Cantilevers Dominik Kramer Raghavan Nadar Viswanath and Jo1rg Weissmu1ller Institut fu r Nanotechnologie Forschungszentrum Karlsruhe GmbH 76021 Karlsruhe Germany and Fachrichtung Technische Physik UniVersita t des Saarlandes 66041 Saarbru cken Germany Received January 13 2004 ABSTRACT NANO LETTERS 2004 Vol 4 No 5 793 796 We report the preparation of composite foils consisting of two layers one solid gold and one nanoporous gold Tip displacements of several millimeters are observed when the foils are immersed in aqueous electrolytes and the electrochemical potential varied This suggests that nanoporous metals could be used as the active component in actors and it demonstrates for the first time that changes in the surface stress f of the metal electrolyte interface can induce a macroscopic strain orders of magnitude larger than the amplitudes which are reached in conventional cantilever bending experiments used to measure f Changes of the shape of liquid mercury electrodes in response to changes of the electrical potential have been observed as early as the 19th century In 1872 Gabriel Lippmann invented his capillary electrometer in which small voltage differences can be measured by observation of the displacement of a mercury meniscus The Lippmann equation relates the surface tension of a liquid electrode to the electrode potential and it is also a good approximation for solids 1 However the surface stress f of a solid is not even approximately equal to its surface tension and it exhibits a different generally stronger 2 dependence on the potential 1 Furthermore due to the stiffness of solids potential dependent changes in the position or shape of solid surfaces are much smaller than those of liquid electrodes Highly sensitive extensometers3 were used to monitor the strain and in the past decade surface stress changes have been measured using atomic force microscope type techniques thin metal films on the cantilevers are used as electrodes and techniques as for instance laser beam deflection allow the tip displacement in the lower nanometer range e g in ref 4 induced by changes in the surface stress to be measured 5 10 Because the surface stress in solids could hitherto only be detected in a laboratory environment using sophisticated equipment it might be considered as an exotic phenomenon of little practical relevance Even in thin film growth where the Corresponding author E mail Dominik Kramer int fzk de Ad dress Dr Dominik Kramer Forschungszentrum Karlsruhe GmbH Institut fu r Nanotechnologie PO Box 3640 D 76021 Karlsruhe Germany Tel 49 0 7247 82 6379 Fax 49 0 7247 82 6369 Forschungszentrum Karlsruhe Universita t des Saarlandes 10 1021 nl049927d CCC 27 50 2004 American Chemical Society interface induced stress may be large its importance remains the subject to current research 11 More recently surface stress induced length changes of 1 5 m have been observed in nanoporous mm sized platinum cubes an indication that the capillary effects can be enhanced by increasing the surface to volume ratio 12 which takes on exceptionally large values in porous nano structures Since the pressure in the bulk required to balance the surface stress scales with independent of the geometry of the microstructure 13 large volume changes and a considerable mechanical work density result from changes in the surface stress of the nanoporous metal 12 Therefore it has been suggested that such materials may be attractive for use as actuators 14 However integration of the porous metal into a device requires that it can be precisely and reproducibly shaped and that it can be bonded to the parts of the device that transmit displacement and load It has not been demonstrated so far how this can be achieved using nano powder compacts furthermore while powder compacts support a considerable hydrostatic pressure their resistance to shear stress may be poor Here we show that nanoporous metals prepared by dealloying a bulk solid solution exhibit similarly large strain amplitudes as nanopowder compacts and that the porous material can be joined to solid metal foils to form a composite cantilever beam actuator The charge induced expansion or contraction of the porous metal gives rise to a biaxial stress component that results in a large bending of the foil In this way the effect of the interface induced stress is amplified so that the deflection becomes visible to the naked eye the tip moves by 3 mm an increase Published on Web 03 31 2004 Figure 1 Scanning electron micrograph of the nanoporous gold structure obtained by etching silver gold alloy in perchloric acid by the factor 106 compared to previous cantilever bending experiments using a planar surface This demonstrates that changes in the surface stress of nanoporous metals can be exploited to do work in cantilever bending analogously to what was recently reported for carbon nanotubes 15 vanadium oxide nanofibers 16 and conducting polymers 17 Dealloying the selective dissolution of the less noble component from a solid solution is well known to result in nanoporous structures 18 Dealloying is attractive as a tech nique for preparing nanoporous solids since it can be applied irrespective of the shape of the active part of a device including conceivably lithographically shaped miniaturized components Our samples were obtained by the dealloying of Ag75Au25 master alloy sheets see Methods Figure 1 shows a scanning electron microscopy image of the nano porous gold microstructure The ligament size is ca 20 nm Cuboids of porous gold of dimension 1 2 1 2 1 mm3 were investigated in a commercial dilatometer equipped with an in situ electrochemical cell Figure 2A is the cyclic voltammogram current vs potential curve of a nanoporous gold sample immersed in 50 mM sulfuric acid recorded in situ in the dilatometer cell The potential limits are given by the onset of hydrogen evolution ca 0 25 V and gold oxidation above 1 V The voltammogram in Figure 2A is typical of a polycrystalline gold surface The current is almost constant over the entire potential range indicating a continuous capacitive double layer charging and discharging in agreement with the known tendency of SO4 anions to interact only weakly with Au 19 Figure 2B shows the change L in sample length versus the time as the potential is cycled between 0 26 and 1 05 V in 50 mM H2SO4 The length changes periodically and reversibly with the potential with a small irreversible shrinking superimposed to that When the reversible part of L is plotted versus the potential Figure 2C it is apparent that the length of the sample can be changed reproducibly by controlling the potential with a small hysteresis of 0 1 V or 0 02 m The charge was obtained by integration of the current of Figure 2A and by setting the potential of zero charge pzc to 0 25 V compare ref 20 The graph of strain versus charge Figure 2E is highly reversible and linear both Figure 2 In situ dilatometry using 15 succesive cycles of the potential of a cuboid nanoporous gold sample in 50 mM sulfuric acid A Cyclic voltammogram current I versus the electrochemical potential E B Length change L versus time t during the 15 cycles of A C Reversible part of L versus E obtained by subtraction of an constant arbitrary value for each cycle D Total charge Q versus E E L L0 versus Q A and C E display results of all 15 cycles superimposed 794 Nano Lett Vol 4 No 5 2004 in the negatively and positively charged regimes it exhibits a change in slope near the pzc A similar linear correlation has been observed for a Au 111 surface by STM 21 22 but the break near the pzc of Figure 2E was not resolved there It is a matter of debate in how far the potential dependence of the surface stress reflects the details of the bonding of adsorbates to the surface see ref 10 and references therein We have carried out experiments using perchloric acid as the electrolyte and found the results to be in qualitative agreement with Figure 2 see Supporting Information Since the ClO4 ion adsorbs even more weakly than SO4 this finding is compatible with the notion that the potential induced strain does not intrinsically require the formation of the chemical bonds involved in specific adsorption this would imply that the change in surface stress reflects the modified bonding in the space charge layer within the metal surface 2 12 Two further observations in support of this notion are i whereas we find Au to contract at negative potential carbon nanotubes show the opposite effect expansion upon negative charging 15 which indicates that the change in surface stress is strongly related to the nature of the bonding in the solid and ii in situ X ray adsorption near edge spectroscopy XANES data show a significant change in d band occupancy in Pt nanoparticles as the Pt electrolyte interface is charged confirming that the superficial electronic structure of the solid can be changed 23 If the change in surface stress and the surface induced strain in our samples are indeed a consequence of the modified bonding in the metal then the results provide support for a more general concept 24 by controlling the net charge in space charge layers at metal surfaces one can modify the electronic density of states and thereby the local properties of the matter at the surface In nanomaterials which have a large surface to volume ratio this will result in changes of the overall properties opening a way for tuning all those materials properties that depend on the density of states The action of the surface stress can be amplified by use of bilayer foils Each of the foils consists of a layer of porous Au bonded to a layer of solid Au see the cross sections in Figure 3A When the foil is immersed in an electrolyte and its potential varied then the porous layer will tend to expand or contract whereas the solid layer will tend to maintain its dimensions This will result in shear stress at the interface between the two layers and in a bending of the foil quite analogous to the effect of the differential thermal expansion used in bimetal thermometers A similar arrangement has also been used to produce carbon nanotube actuators 15 To make the bilayer foils a 2 mm thick sheet of silver gold alloy was cold welded to a 0 5 mm thick sheet of pure gold by rolling After reducing the thickness of the stack to 30 m by further rolling the resulting foil was annealed for stress relief and strips 35 40 mm long and 2 mm wide cut from it Dealloying resulted in a composite foil consisting of a 6 m thick layer of solid Au covered with 24 m of porous Au Two foils were immersed in 1 M HClO4 and wired as the working and the counter electrodes respectively Figures 3A and 3B show a schematic drawing and a photograph of the experimental setup Both foils undergo a Nano Lett Vol 4 No 5 2004 Figure 3 Illustration of the operation of the composite foils A schematic cross section through an electrochemical cell comprising two identical foils that serve interchangeably as working electrode and counter electrode B D photographs of an electrochemical cell with two bimetallic stripes nanoporous gold on gold similar to the schematic in A The electrolyte is 1 M perchloric acid The lower scale of the ruler is calibrated in mm C D Two enlarged views of the cell in B showing the tip of one of the foils with two different voltages applied between the two foils 1 V C and 1 V D It is seen that when the voltage is inversed the tip moves by ca 3 mm The arrows serve as reference markers emphasizing the tip displacement reversible bending as the voltage is changed Figures 3C D show enlarged views of the tip of one of the foils before and after inverting the applied voltage When the potential difference between the electrodes is switched from 1 V to 1 V the tip moves by as much as 3 mm Thus compared to cantilever bending experiments using planar surfaces the displacement resulting from surface stress changes has increased from few nanometers to the millimeter regime that is by about a factor of 106 A video clip showing the actuator operation is displayed as Supporting Information For the first time the effects potential induced changes of the interface stress which had previously required sophisticated experimental equipment have become visible to the naked eye For actuator applications the response time is important Figure 4A shows the time dependent L during a series of 795 Figure 4 A Length change L of the sample in 50 mM sulfuric acid versus time measured in the dilatometer during a series of potential jumps from 0 2 to 1 V and back dashed line potential B Frequency dependence of the amplitude during potential jumps rectangular wave in sulfuric acid Large squares Amplitude of the charge curve Small circles Amplitude of the length change as measured in the dilatometer The dilatometers maximum sampling rate of 10 s 1 limits the experimental strain amplitude at high frequency potential jumps from 0 2 V to 1 V and back The half times of the jumps in current and strain are 220 and 270 ms Because of the limited sampling rate 10 s 1 of the dilatometer the time constant obtained from the charging curves is considered more accurate The strain amplitude at a frequency of 0 3 Hz is almost identical to that during slower switching Figure 4B which is consistent with the response time given above The bilayer foils react similarly fast despite the drag of the electrolyte The intrinsic time scale is given by the time constant of the charging current which was determined as 25 ms considerably faster than in the thicker dilatometer samples This agrees qualitatively with the expectation that the drift of ions into the pores will be accelerated as the path is shortened The large mechanical response induced by changes in the surface stress predestines porous gold as an active component in sensors especially if its surface is modified by adsorption e g of molecules functionalized by thiol groups These can be chosen to react selectively with specific molecules for instance antibodies the reaction changes the surface stress e g by steric repulsion of the product and sensors detecting these changes have been proposed and tested 8 25 27 Their sensitivity may be significantly enhanced by using nano porous layers instead of planar surfaces In addition to its performance as a simple actor producing reversible strain controlled by an applied voltage the device shown in Figure 3 can also be regarded as a primitive voltmeter If the tip displacement was observed with an optical microscope as in Lippmann s device it would be suited to measure small voltage differences Thus Lipp mann s 19th century voltmeter based on changes of the surface tension of liquid mercury interface has found a modern equivalent based on changes in the surface stress of a solid metal Acknowledgment Stimulating discussions with H Gle iter and support by DFG Center for Functional Nanostruc tures are gratefully acknowledged Supporting Information Available Experimental de tails two additional Figures S1 S2 and a video showing the movement of the bilayer foils This material is available free of charge via the Internet at http pubs acs org References 1 Lipkowski J 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K Langmuir 2000 16 9694 9696 NL049927D 796 Nano Lett Vol 4 No 5 2004 本文研究了一種雙層復(fù)合材料箔的制備 其中一層為固體金 另一層為納米多孔金 當(dāng)箔浸入電解質(zhì)水溶液中 并改變?nèi)芤旱碾娀瘜W(xué)勢(shì) 可以觀察到數(shù)毫米大小的端部位移 這一現(xiàn)象表明納米多孔金屬可以作為作動(dòng)器中的應(yīng) 激組件 還首次揭露了金屬 電解液界面上表面應(yīng)力 f 的改變將引起宏觀應(yīng)變 該應(yīng)變的大小比用于測(cè)量表面應(yīng)力 f 的傳統(tǒng)懸臂梁彎曲實(shí)驗(yàn)中所能達(dá)到的振幅要高幾個(gè)數(shù)量級(jí) 早在 19 世紀(jì) 人們就已觀察到 在電勢(shì)改變時(shí)液態(tài)汞電極將會(huì)產(chǎn)生形狀改變 1872 年 Gabriel Lippmann 加布 里埃爾 李普曼 外國(guó)人的名字不必翻譯 發(fā)明了毛細(xì)靜電計(jì) 可通過(guò)觀察一個(gè)水銀彎曲面的位移來(lái)測(cè)得微小的 電壓改變 李普曼方程建立了液態(tài)電極的表面張力和電極電勢(shì)的相關(guān)關(guān)系 而且對(duì)固體電極也可以獲得令人滿意 的近似結(jié)果 1 然而 固體的表面應(yīng)力 f 并不近似等于其表面張力 并表現(xiàn)出對(duì)電勢(shì)的不同依賴性 1 一般而 言依賴性更強(qiáng) 2 進(jìn)一步講 由于固體具有一定的剛度 其表面依賴于電勢(shì)的位置和形狀改變遠(yuǎn)小于液體電極 高敏延展計(jì) 3 用于監(jiān)測(cè)應(yīng)變 在過(guò)去的十年間 利用原子力顯微鏡技術(shù)已可測(cè)量表面應(yīng)力的改變 將薄金屬片置 于懸臂梁上作為電極 然后采取激光束偏轉(zhuǎn)分析技術(shù) 就可以得到由表面應(yīng)力改變引起的懸臂梁末端位移 可達(dá) 到納米級(jí) 如參 4 5 10 然而由于目前僅能在實(shí)驗(yàn)室環(huán)境內(nèi)依托精密儀器檢測(cè)到固體的表面應(yīng)力 所以這一發(fā) 現(xiàn)還只被視作一種缺少實(shí)用價(jià)值的 獨(dú)特 現(xiàn)象 即使在界面導(dǎo)致應(yīng)力較大的薄膜生長(zhǎng)方面 其重要性也有待進(jìn) 一步研究 11 最近 在具有毫米量級(jí)尺寸的納米多孔鉑立方體上觀測(cè)到了由于表面應(yīng)力引起的長(zhǎng)度變化 達(dá)到 1 5 m 這說(shuō)明 提高表體比 能夠放大毛細(xì)管效應(yīng) 12 而多孔納米結(jié)構(gòu)的表體比非常大 由于塊體材料中平衡表面應(yīng)力所需的 體積應(yīng)力會(huì)隨 變化 而 不依賴于微觀結(jié)構(gòu)的幾何特性 所以納米多孔金屬的表面應(yīng)力變化將引起可觀的機(jī) 械功密度及大的體積改變 12 因此 這類金屬被認(rèn)為在作動(dòng)器制造方面前景誘人 14 然而 將多孔金屬集成在設(shè) 備上需要精確且可重復(fù)化的多空金屬成型工藝 并且能與設(shè)備上傳遞位移和荷載的部分緊密聯(lián)結(jié) 目前為止 使 用納米粉末一體化壓實(shí)技術(shù)還不能達(dá)到這些要求 因?yàn)殡m然一體化納米粉末抗壓能力優(yōu)良 但其抗剪能力很差 本文中展示了利用固熔塊體脫合金法制備的納米多孔金屬不僅具有與一體化納米粉末壓實(shí)相近的大應(yīng)變幅值 并 可與固體金屬箔有效粘結(jié) 制造出一種復(fù)合懸臂梁作動(dòng)器 通電后 多孔金屬發(fā)生延展或收縮 產(chǎn)生雙軸平面應(yīng) 力分量 從而引起箔的大幅度彎曲 這樣一來(lái) 界面導(dǎo)致應(yīng)力所產(chǎn)生的效應(yīng)被放大至肉眼可見(jiàn)的撓度 梁末端移 動(dòng)了 3mm 比之前使用光滑平面的懸臂梁彎曲實(shí)驗(yàn)提高了 106 倍 這說(shuō)明納米多孔金屬中表面應(yīng)力的變化可被用 于懸臂梁彎曲實(shí)驗(yàn) 類似于最近報(bào)導(dǎo)的碳納米管 15 釩氧化物納米纖維 16 和導(dǎo)電高分子 17 眾所周知 將固溶物中占比較小的組分通過(guò)脫合金法選擇性溶解 能夠獲得納米多孔結(jié)構(gòu) 18 脫合金法作為一種 制備納米多孔固體的技術(shù) 其優(yōu)點(diǎn)在于應(yīng)用時(shí)不受設(shè)備應(yīng)激部件形狀的限制 包括刻蝕技術(shù)成型的微型組件 本文所使用的試樣是通過(guò)對(duì) Ag75Au25 母合金片進(jìn)行脫合金腐蝕制備的 詳見(jiàn) 方法 一章 圖 1 為納米多孔 金微觀結(jié)構(gòu)的掃描電子顯微鏡照片 系帶尺寸約為 20nm 使用配備有原位電化學(xué)電池的商業(yè)膨脹計(jì) 對(duì)尺寸為 1 2 1 2 1mm3 的多孔金長(zhǎng)方體進(jìn)行了研究 圖 2A 是浸入 0 05mol L 硫酸的納米多孔金樣本的循環(huán)伏安圖 電流 電勢(shì)曲線 曲線數(shù)據(jù)原位記錄于膨脹計(jì)電池中 電勢(shì)極 限對(duì)應(yīng)于氫開(kāi)始析出 約 0 25 V 和金開(kāi)始氧化 高于 1V 圖 2A 是多晶金表面典型的伏安圖 整個(gè)電勢(shì)值域 內(nèi) 電流值幾乎保持恒定 表示了一種連續(xù)式電容性雙層充放電現(xiàn)象 與 SO4 離子僅能與金發(fā)生微弱的反應(yīng)的已 知結(jié)論相一致 19 圖 2B 為電勢(shì)在 0 26V 至 1 05V 之間循環(huán)時(shí) 浸在 0 05mol L 硫酸溶液中的試樣長(zhǎng)度改變量 L 隨時(shí)間的變化曲 線 長(zhǎng)度隨電壓作周期性 往復(fù)變化 并伴隨微量的不可逆疊加收縮 當(dāng)建立長(zhǎng)度改變量 L 的可逆部分隨電 勢(shì)變化的曲線 圖 2C 時(shí) 可以清晰地得出如下結(jié)論 通過(guò)調(diào)控電勢(shì)便能重復(fù)化地改變樣本長(zhǎng)度 約有 0 1V 或 0 2 m 的微量滯后 其中 將零勢(shì)能點(diǎn) pzc 設(shè)為 0 25V 與參 20 對(duì)比 并對(duì)圖 2A 中的電流進(jìn) 行積分 就可以計(jì)算出電量 應(yīng)變 電量曲線如圖 2E 所示 無(wú)論在正電荷還是負(fù)電荷環(huán)境下 曲線都具有高度的 可逆性和線性性質(zhì) 并在零勢(shì)能點(diǎn)附近出現(xiàn)了斜率變化 使用掃描隧道顯微鏡 可在金 111 的表面觀察到相似 的線性相關(guān)性 21 22 但沒(méi)有給出圖 2E 中零勢(shì)能點(diǎn)附近的中斷 表面應(yīng)力的電勢(shì)依賴性能在多大程度上反映被吸附物與表面之間的結(jié)合細(xì)節(jié) 是有待于討論的問(wèn)題 見(jiàn)參 10 及其參考文獻(xiàn) 使用高氯酸作為電解液 我們發(fā)現(xiàn)了與圖 2 定性一致的實(shí)驗(yàn)結(jié)果 見(jiàn)支持信息 由于 ClO4 離子吸附力比 SO4 還弱 這一發(fā)現(xiàn)與如下概念一致 電勢(shì)誘導(dǎo)產(chǎn)生的應(yīng)變本質(zhì)上并不要求在特定吸附中形成化學(xué) 鍵 這也意味著表面應(yīng)力的變化反映了金屬表面空間電荷層中結(jié)合鍵的修正 2 12 另外兩個(gè)深入觀察結(jié)果也支持 了這一概念 i 負(fù)電位下 金將收縮 而碳納米管卻相反地展現(xiàn)出延展效應(yīng) 15 這表明表面應(yīng)力變化與固體 成鍵本質(zhì)密切相關(guān) ii 原位 X 射線吸收近邊結(jié)構(gòu)譜數(shù)據(jù)顯示 對(duì)鉑 電解質(zhì)交界面通電時(shí) 鉑納米粒子的 d 帶 占有情況會(huì)發(fā)生顯著變化 證實(shí)了固體的表面電子結(jié)構(gòu)可以改變 23 如果我們的試樣中表面應(yīng)力的變化和表面誘 導(dǎo)應(yīng)變確實(shí)是由金屬中結(jié)合鍵的修正引起的 那么該結(jié)果將支持一個(gè)更一般層面的概念 24 通過(guò)控制金屬表面空 間電荷層中的凈電荷 可以調(diào)整物質(zhì)表面的電子態(tài)密度從而改變其表面局部特性 對(duì)于有著大表體比的納米材料 來(lái)說(shuō) 這將導(dǎo)致一系列整體性能變化 并為調(diào)控所有基于電子態(tài)密度的材料性能提供了一種新的方法 用雙層箔可以放大表面應(yīng)力作用 每層箔都由一層多孔金和一層固體金結(jié)合而成 橫截面如圖 3A 所示 將箔浸 入電解液 并改變其電勢(shì) 多孔金層