某彈體尺寸自動(dòng)測(cè)量設(shè)備開(kāi)發(fā)控制系統(tǒng)設(shè)計(jì)【說(shuō)明書(shū)+CAD】

購(gòu)買(mǎi)設(shè)計(jì)請(qǐng)充值后下載，資源目錄下的文件所見(jiàn)即所得，都可以點(diǎn)開(kāi)預(yù)覽，資料完整，充值下載可得到資源目錄里的所有文件?！咀ⅰ浚篸wg后綴為CAD圖紙，doc,docx為WORD文檔，原稿無(wú)水印，可編輯。具體請(qǐng)見(jiàn)文件預(yù)覽，有不明白之處，可咨詢(xún)QQ:12401814 Novel Design and 3-D Printing of Nonassembly Controllable Pneumatic RobotsAbstractAdditive manufacturing (known as 3-D print-ing to the public) technologies are capable of fabricating mechanical parts without the limitation of geometric complexity. If properly designed, a mechanism can also be automatically fabricated without the need of assembly. Considering these capabilities of 3-D printing, this paper presents a novel pneumatic robot design that can be fabricated by 3-D printing processes without the need of assembly. The key element of the proposed robot is the innovative design of a pneumatic stepper motor that allows control of multi motion pattern modes. The proposed pneumatic stepper design is based on a fan motor, thus, having a low requirement on airtightness, which makes it possible for 3-D printing fabrication. For angular motion control, a roller valve is added to the fan motor design. By controlling the air pressure of the roller valve, continuous motion and stepping motion can be obtained. Experiments have shown that the angular velocity can also be controlled by varying the roller-valve air pressure. The effectiveness of the proposed concepts has been demonstrated by a 3-D printed nonassembly pneumatic robot. The printed robot, when connected with air tubes and a pneumatic controller, can perform simple pick and place operations. It is argued that the future functional nonassembly pneumatic robotic systems could be 3-D printed for relevant industries.Neumatic actuation is widely used in industrial application for its low cost, compact size, high power to weight ratio, reliability and security. In some cases, pneumatic actuation is even preferable to electric ones, especially in medical applications, such as magnetic resonance medical imaging equipment and high-risk environments like inflammable gas vessels or pipes. Some classic pneumatic actuatious, rotary or linear, have been fully developed . However, such classic actuations have high requirement on air impermeability and precision of fabrication and assembly, which increase the production time and cost. In addition, the error resulted from fabrication and assembly process may lead to a reduced precision in controlled.One of the key pneumatic actuators in pneumatic systems is the pneumatic stepper motor. Recent effort has been concentrating on developing more accurate pneumatic stepping motors, or stepper motor that is compliant to magnetic resonance imaging (MRI) environment. From the literature, four types of pneumatic stepper motors have been proposed. Stoianovici et al., developed a MRI compliant stepper motor called PneuStep, whose resulting step size could reach 3.33 (angular) and 0.055 mm (linear). The working principle of PneuStep . The main structures are composed of three diaphragm cylinders, a set of internal gears, and output cranks. The ring gear is fixed, while the outer gear is connected to an output shaft. The motor is able to act in stepper mode by sequentially actuating the three diaphragm cylinders. another type of stepper motor developed by Masamune et al. The motor is composed of three pistons within their respective syringes and two types of gears: a rotational gear and three direct acting gears. There is a certain stagger angle be-tween the rotational gear and the direct acting gear. Every time the acting gear moves up and contacts the rotational gear, the rotational gear will rotate a certain stepper angle to couple with the acting gear. Therefore, the motor could constantly output stepper motion by sequenced cooperation of the three acting gears. The stepper developed by Chen et al. adopts similar principles, but has the smallest size among all these pneumatic stepper motors with only 10 mm in diameter. However, these reported stepping motors rely on either the inter meshing inter-action of different sets of gears, or the cooperation of the linear motion of piston crank and linkage mechanism to realize the stepping motion, which requires precision manufacturing and assembly. Another novel design proposed by Chen et al.refers to the principle of two stroke engine. The use of crank transforms the linear motion of the two coupled pistons to rotational motion of the output shaft. The actuation system can rotate 3.6 in each step. Compared with the previous designs, this concept greatly simplifies the working principle and mechanical design of conventional pneumatic stepper motor. However, the main disadvantage of these stepping motors is speed discontinuity and vibration. In many cases, it is desirable if a motor can switch motion patterns between continuous mode and stepping mode. The latest design proposed by Chen et al. is able to output continuous rotation according to its working principle, which is similar to a vehicle engine. But it requires a precise control on the cooperation of two pistons and the design is quite complicated. An unsuccessful control strategy may result in a very large torsional torque on the crank which may cause great damage. All the above stepper motor designs have complex mechanisms, making them unsuitable for 3-D printing.Additive manufacturing, known as 3-D printing to the public, is a fabrication method where physical objects are constructed layer by layer , As opposed to conventional method, 3-D printing can fabricate parts and mechanisms directly from the computer-aided design model, regardless of the shape complexity. Due to this property, 3-D printing technologies can greatly shorten the product design circle, save time and cost, and provide access to early verification of product designs,. In traditional manufacturing processes, individual parts have to be fabricated first, and then, assembled into final mechanisms which are time and money consuming. Moreover, the assembly process requires high accuracy. Otherwise, the final mechanism can easily get stuck and fail to work due to inappropriate positions and match-up of move able parts. On the contrary, 3-D printing allows one-step fabrication of complex mechanisms, such as multi links and multi articulated mechanisms without the need of any assembly of components. It has a great potential to change the way how mechanisms and robotic systems are currently designed and built.Three-Dimensional printing of nonassembly mechanisms and robotic systems has been researched for quite a long time. Many different 3-D printing processes are applied to fabricate robotic mechanisms. Fused deposition modeling was used by Gosselin et al., to build several mechanisms, such as parallel manipulator. These rapidly printed mechanisms required further assembly of mechanism parts. Cutkosky et al., at Stanford University used shape deposition manufacturing , to develop a flexible joint with embedded components. These components were inserted to the mechanism during its fabrication as an integrated process rather than post fabrication assembly. However, such process is challenging, because it requires high surface quality and geometric accuracy of the contact areas, and precise positioning and fix turing of embedded components. These requirements brought extra complexities and difficulties into the design and fabrication process. Mavroidis et al., had contributed to building nonassembly robotic system with embedded parts, such as robotic hand and radio-controlled vehicle.Their works advance the development of one-step fabrication of fully functional, multi articulated mechanism with embedded components. However, the requirement of accurate insertion of the embedded components is still a tough problem that makes AM less cost-effective, and is only applicable to selected applications. Chen et al., at the University of Hong Kong focus on the shape optimization and analysis of nonassembly joint mechanisms using different 3-D printing techniques . These works provide alternative ideas of 3-D printing tolerance-tight mechanisms. They also contributed to the novel design of nonassembly mechanisms and systems. However, they did not take mechanism actuation into consideration. The automated fabrication of nonassembly, fully functional mechanism is by now still the dream of researchers in the 3-D printing community. New AM processes or AM compatible processes that support 3-D printing of functional materials is under active research, because functional materials may potentially be designed to function as actuators. Such actuators might be printed through layered manufacturing during fabrication. However, such multi material 3-D printers are still under research. Overall, it is highly desirable to print the actuators in situ the robotic mechanism printing process.To the best knowledge of the authors, the proposed research reported in this paper is the first automatically 3-D printed robotic mechanisms without the need of assembly, or embedding other actuating components. The 3-D printed robot can plug (to a controller) and play (pick and place). This paper demonstrates a new effort to fabricate a fully functional nonassembly robot without any inserts, such as mechanical connecting pins and electronic actuators. The proposed effort is based on pneumatic actuation. The usage of a pneumatic actuator as the prime mover can effectively eliminate the insertion of circuits and electronic parts for robotic actuation. Since the proposed pneumatic robot is entirely made of polymer material that is nonmagnetic and dielectric, it has great potential in applications where electricity is not allowed or preferred, such as working in MRI equipment or working in high risk environments like inflammable gas vessels or pipes. Because previous pneumatic stepper mo-tors are designed with a large amount of assembly and material combination in mind, they cannot be used in this research. In this research, an innovative roller-valve-based pneumatic step-per motor design is proposed. The proposed design can be easily integrated into a robotic mechanism and fabricated without the need of assembly. In addition, unlike previously reported pneumatic stepper motors that have speed limitation and speed discontinuity problems, the proposed pneumatic stepper motor design allows velocity control, and the switch between continuous motion mode and stepping mode. Even though only a simple robotic mechanism is presented in this paper, it is hoped that this early research might arouse interest in 3-D printing of nonassembly and fully functional pneumatic robots. Furthermore, we are confident that the proposed concept of the nonassembly robotic design and fabrication based on 3-D printing can bring new in-sight into design innovation of various robots, such as household robots, industrial robots, and so on.Three-dimensional printing technology has many advantages. The simple articulated joint requires at least three parts: link 1, link 2, and the hinge pin. These three parts have to be manufactured individually with different machine tools, and an extra assembly process is required. On the contrary, 3-D printing needs only digital assembly by making provision of a clearance between parts with relative motion. The digitally assembled model is constructed layer by layer. This 3-D printed nonassembly joint clearly shows the reduction in the component number and the elimination of post assembly. Such reduction and simplification not only save cost and raise efficiency, but also improve the stability and reliability of the mechanism. Three-dimensional printing has made great improvements in terms of manufacturing accuracy, material property, surface quality, hardness, toughness, and part durability over the years. These improved features make 3-D printing of nonassembly fully functional devices more and more attractive.The design and development of functional mechanisms and robotic systems that can be fabricated without the need of assembly is very attractive .conceptual diagram of PneuStep, the first pneumatic stepper designed by Stoianovici et al. It consists of four main parts that are represented by different colors in Fig. 3. The step motion is achieved by sequentially pressurizing three diaphragm cylinders as D1D2D3. Al-though PneuStep has great performance, its design complexity leads to a high manufacturing cost and long development cycle time. The motor design has more than 25 different parts. The assembly of the individual parts together with fasteners, bearings, and connectors is not an easy task. The application of three crank mechanisms to produce planetary motion requires precise fabrication and assembly. Otherwise, it is more likely to result in interference between moving parts, which can lead to motor failure.非組裝機(jī)制可控氣動(dòng)機(jī)器人新穎的設(shè)計(jì)和三維印刷摘要：增材制造業(yè)(稱(chēng)為三維打印技術(shù))技術(shù)能夠制造機(jī)械零件，沒(méi)有幾何復(fù)雜性的限制。如果設(shè)計(jì)得當(dāng),也可以自動(dòng)的機(jī)制不需要組裝制造。考慮到這些三維打印的功能,本文提出一種新穎的氣動(dòng)機(jī)器人設(shè)計(jì)可以通過(guò)三維印刷制作過(guò)程不需要組裝的關(guān)鍵要素,提出了機(jī)器人創(chuàng)新設(shè)計(jì)的氣動(dòng)控制步進(jìn)電機(jī),使多運(yùn)動(dòng)模式的模式。該氣動(dòng)步進(jìn)設(shè)計(jì)是基于一個(gè)風(fēng)扇電機(jī),因此,在密封性要求較低,這使得有可能3 d印刷制作。角運(yùn)動(dòng)控制輥閥被添加到風(fēng)扇電機(jī)的設(shè)計(jì)。通過(guò)控制輥的空氣壓力閥,可以獲得連續(xù)運(yùn)動(dòng)和步進(jìn)運(yùn)動(dòng)。實(shí)驗(yàn)表明,角速度也可以由不同滾動(dòng)閥空氣壓力。提出了概念并證明了三維打印氣動(dòng)機(jī)器人有效性。印刷的機(jī)器人,當(dāng)與空氣管和氣動(dòng)控制器,可以執(zhí)行簡(jiǎn)單的選擇和地點(diǎn)操作。認(rèn)為未來(lái)氣動(dòng)機(jī)器人系統(tǒng)3 d印刷可以應(yīng)用于相關(guān)行業(yè)。氣動(dòng)驅(qū)動(dòng)廣泛用于工業(yè)，低成本、小體積、高功率,可靠性和安全性。在某些情況下,氣動(dòng)驅(qū)動(dòng)甚至比電動(dòng)的也多,特別是在醫(yī)學(xué)應(yīng)用,如核磁共振醫(yī)療成像設(shè)備和高風(fēng)險(xiǎn)環(huán)境如易燃?xì)怏w容器或管道。一些經(jīng)典的氣動(dòng)驅(qū)動(dòng)、旋轉(zhuǎn)或直線(xiàn),已經(jīng)發(fā)育完全。然而,這樣的經(jīng)典動(dòng)作要求高氣密性和制造和裝配精度,增加了生產(chǎn)時(shí)間和成本。此外,由于制造和裝配過(guò)程可能導(dǎo)致控制精度降低。在氣動(dòng)系統(tǒng)的關(guān)鍵是氣動(dòng)執(zhí)行機(jī)構(gòu)，就是氣動(dòng)步進(jìn)電機(jī)。最近集中精力發(fā)展更精確的氣動(dòng)步進(jìn)電機(jī)或步進(jìn)電機(jī)用于磁共振成像的環(huán)境。從一些文獻(xiàn)中看到提出了氣動(dòng)步進(jìn)電機(jī)的四種類(lèi)型。一種叫做PneuStep核磁共振兼容的步進(jìn)電機(jī),其步長(zhǎng)可以達(dá)到3.33(角)和0.055毫米(線(xiàn)性)。PneuStep的的主要結(jié)構(gòu)是由三個(gè)氣缸膜片,一組內(nèi)部齒輪和輸出曲柄。外齒輪齒圈固定,而連接到一個(gè)輸出軸。電機(jī)能夠在步進(jìn)順序模式驅(qū)動(dòng)三個(gè)氣缸膜片。另一種類(lèi)型的步進(jìn)電機(jī)馬達(dá)由三個(gè)活塞在各自的注射器和兩種類(lèi)型的齒輪:一個(gè)旋轉(zhuǎn)裝置和三個(gè)直接傳動(dòng)的齒輪。有一定的交錯(cuò)角之間的轉(zhuǎn)動(dòng)齒輪直接傳動(dòng)的齒輪。每次齒輪移動(dòng)和接觸轉(zhuǎn)動(dòng)齒輪,轉(zhuǎn)動(dòng)齒輪會(huì)轉(zhuǎn)動(dòng)一個(gè)步進(jìn)角。因此,電動(dòng)機(jī)可以通過(guò)測(cè)序不斷輸出步進(jìn)運(yùn)動(dòng)的三個(gè)齒輪。開(kāi)發(fā)的步進(jìn)電機(jī)采用相似的原理,但最小的大小在所有這些氣動(dòng)步進(jìn)電機(jī)只有10毫米直徑。然而,這些報(bào)道步進(jìn)電動(dòng)機(jī)依靠不同的齒輪互相嚙合的相互作用,或合作的線(xiàn)性運(yùn)動(dòng)活塞曲柄和連桿機(jī)制實(shí)現(xiàn)步進(jìn)運(yùn)動(dòng),這需要精密制造和組裝。陳等人提出的另一個(gè)新穎的設(shè)計(jì)指的是二沖程發(fā)動(dòng)機(jī)。使用曲柄將兩個(gè)耦合的活塞的直線(xiàn)運(yùn)動(dòng)轉(zhuǎn)換為輸出軸的旋轉(zhuǎn)運(yùn)動(dòng)。驅(qū)動(dòng)系統(tǒng)可以每一步旋轉(zhuǎn)3.6。與前面的設(shè)計(jì)相比,這個(gè)概念極大地簡(jiǎn)化了傳統(tǒng)氣動(dòng)工作原理和機(jī)械設(shè)計(jì)的步進(jìn)電機(jī)。然而,這些步進(jìn)電機(jī)的主要缺點(diǎn)是速度不連續(xù)和振動(dòng)。在許多情況下,它是可取的,如果電機(jī)開(kāi)關(guān)運(yùn)動(dòng)模式之間的連續(xù)模式和步進(jìn)模式。陳等人提出的最新設(shè)計(jì)是能夠輸出連續(xù)旋轉(zhuǎn)根據(jù)其工作原理,這是類(lèi)似于一個(gè)汽車(chē)引擎。但它需要一個(gè)精確的控制兩個(gè)活塞和設(shè)計(jì)上的合作相當(dāng)復(fù)雜。一次不成功的控制策略可能會(huì)導(dǎo)致一個(gè)非常大的扭轉(zhuǎn)力矩的曲柄可能會(huì)導(dǎo)致巨大的損失。上述所有步進(jìn)電機(jī)設(shè)計(jì)復(fù)雜的機(jī)制,使他們不適合三維印刷。增材制造,稱(chēng)為三維印刷,是一種制造方法,在物理對(duì)象是一層一層地建造。與傳統(tǒng)方法,三維打印可以制造部分直接從計(jì)算機(jī)輔助設(shè)計(jì)模型和機(jī)制,無(wú)論形狀的復(fù)雜性。由于這個(gè)屬性,三維打印技術(shù)可以大大縮短產(chǎn)品設(shè)計(jì)圈,節(jié)省時(shí)間和成本,并提供訪(fǎng)問(wèn)驗(yàn)證產(chǎn)品設(shè)計(jì)的早期,在傳統(tǒng)的生產(chǎn)過(guò)程中,各個(gè)部分必須的第一,然后組裝成最終的機(jī)制是耗費(fèi)時(shí)間和金錢(qián)。此外,裝配工藝要求精度高。否則,最后機(jī)制很容易卡住,不能工作由于不恰當(dāng)?shù)奈恢煤拖嗯涞目梢苿?dòng)的部分。相反,3 d印刷允許一步制造復(fù)雜的機(jī)制,如多鏈路和多鉸接機(jī)制不需要任何組件的裝配。它有一個(gè)巨大的潛力,改變目前機(jī)制和機(jī)器人系統(tǒng)是如何設(shè)計(jì)和建造。三維打印非組裝機(jī)制和機(jī)器人系統(tǒng)已經(jīng)被研究了很長(zhǎng)一段時(shí)間。許多不同的三維印刷過(guò)程應(yīng)用于制造機(jī)器人機(jī)制。用熔融沉積造型技術(shù),建立幾種機(jī)制,如并聯(lián)機(jī)械手。這些快速印刷機(jī)制需要進(jìn)一步組裝機(jī)制部分。斯坦福大學(xué)使用形狀沉積制造,開(kāi)發(fā)一個(gè)靈活的關(guān)節(jié)與嵌入式組件。這些組件被插入到機(jī)制在其制造作為一個(gè)集成的過(guò)程而不是制造裝配。然而,這樣的過(guò)程是具有挑戰(zhàn)性的,因?yàn)樗枰^高的表面質(zhì)量和幾何精度的接觸區(qū)域,嵌入式組件的精確定位和夾具。這些需求帶來(lái)額外的復(fù)雜性和困難在設(shè)計(jì)和制造過(guò)程。Mavroidis 等人設(shè)計(jì)非組裝機(jī)制機(jī)器人系統(tǒng)預(yù)埋件,如機(jī)械手和無(wú)線(xiàn)電控制車(chē)輛。他們的工作推進(jìn)一步法制造的全功能的發(fā)展,多與嵌入式組件的機(jī)制。然而,準(zhǔn)確的插入嵌入式組件的需求仍然是一個(gè)棘手的問(wèn)題,讓我更少的成本效益,并只適用于選定的應(yīng)用程序。香港大學(xué)的關(guān)注非組裝機(jī)制聯(lián)合機(jī)制的形狀優(yōu)化和分析使用不同的三維打印技術(shù)。這些作品提供替代的想法三維印刷公差緊機(jī)制。他們也促成了非組裝機(jī)制機(jī)制和系統(tǒng)的設(shè)計(jì)。然而,他們并沒(méi)有考慮驅(qū)動(dòng)機(jī)制。非組裝機(jī)制自動(dòng)化制造,功能齊全的機(jī)制現(xiàn)在仍然在三維印刷人員的夢(mèng)想社區(qū)。新是過(guò)程還是兼容的過(guò)程支持3 d打印功能材料的研究很活躍,因?yàn)楣δ懿牧峡赡鼙挥脕?lái)作為執(zhí)行機(jī)構(gòu)。這種執(zhí)行機(jī)構(gòu)可能通過(guò)分層印刷生產(chǎn)制造期間。然而,這樣的復(fù)合材料3 - d打印機(jī)仍在研究中?？偟膩?lái)說(shuō),這是非常可取的打印驅(qū)動(dòng)器原位機(jī)器人印刷過(guò)程的機(jī)制。針對(duì)知名的設(shè)計(jì)師,本文提出研究報(bào)告是自動(dòng)三維印刷機(jī)械機(jī)制不需要組裝,或嵌入其他驅(qū)動(dòng)組件。3 d印制機(jī)器人可以插頭(控制器)和播放(選擇和地點(diǎn))。本文演示了一種新的努力制造一個(gè)功能齊全的非組裝機(jī)制機(jī)器人沒(méi)有插入,如機(jī)械連接插腳和電子執(zhí)行器。擬議的工作是基于氣動(dòng)驅(qū)動(dòng)。氣壓傳動(dòng)裝置作為原動(dòng)力的使用可以有效地消除電路和電子零件的插入機(jī)械驅(qū)動(dòng)。自提出氣動(dòng)機(jī)器人完全是由非磁性的高分子材料和介質(zhì),它有巨大的潛力在電力的應(yīng)用程序是不允許或首選,如在MRI設(shè)備或在高危環(huán)境下工作,如易燃?xì)怏w容器或管道。因?yàn)橹暗臍鈩?dòng)設(shè)計(jì)步進(jìn)電機(jī)與大量的組裝和材料組合,他們不能被用于這項(xiàng)研究。在本研究中,基于創(chuàng)新的滾子閥的氣動(dòng)設(shè)計(jì)提出了步進(jìn)電機(jī)。提出設(shè)計(jì)可以很容易地集成到一個(gè)機(jī)器人機(jī)制和捏造不需要組裝。此外,與之前報(bào)道的氣動(dòng)步進(jìn)電機(jī)的速度限制和速度不連續(xù)問(wèn)題,提出氣動(dòng)步進(jìn)電機(jī)設(shè)計(jì)允許速度控制和連續(xù)動(dòng)作模式和步進(jìn)模式之間切換。盡管只有一個(gè)簡(jiǎn)單的機(jī)器人機(jī)制提出了,希望這個(gè)早期研究可能引起興趣非組裝機(jī)制和功能齊全的氣動(dòng)機(jī)器人的三維印刷。此外,我們相信,非組裝機(jī)制機(jī)械設(shè)計(jì)和制造的概念提出基于三維印刷設(shè)計(jì)創(chuàng)新可以帶來(lái)新的見(jiàn)解不同的機(jī)器人,如家用機(jī)器人、工業(yè)機(jī)器人等。三維印刷技術(shù)有許多優(yōu)點(diǎn)。簡(jiǎn)單的鉸接接頭至少需要三個(gè)部分:鏈接,鏈接2,鉸鏈銷(xiāo)。這三個(gè)部分分別與不同的機(jī)床制造,和一個(gè)額外的裝配過(guò)程是必需的。相反,3 d印刷只需要數(shù)字大會(huì)通過(guò)提供與相對(duì)運(yùn)動(dòng)部件之間的間隙。數(shù)字化裝配模型是一層一層地建造。這個(gè)3 d印刷非組裝機(jī)制聯(lián)合清楚地顯示了減少組件數(shù)量和消除后組裝。減少和簡(jiǎn)化不僅節(jié)省成本和提高效率,也提高了穩(wěn)定性和可靠性的機(jī)制。三維印刷有了很大改進(jìn)的制造精度,材料屬性、表面質(zhì)量、硬度、韌性,和持久性。這些改進(jìn)的功能使三維印刷非組裝機(jī)制功能齊全的設(shè)備越來(lái)越有吸引力。功能機(jī)制和機(jī)器人系統(tǒng)的設(shè)計(jì)和開(kāi)發(fā),可以設(shè)計(jì)不需要組裝是很有吸引力的。Stoianovici等人設(shè)計(jì)的第一個(gè)氣動(dòng)步進(jìn)機(jī)由四個(gè)主要部分組成,步驟順序運(yùn)動(dòng)是通過(guò)加壓D1-D2-D3三個(gè)氣缸膜片。盡管PneuStep強(qiáng)大的性能,它的設(shè)計(jì)復(fù)雜性導(dǎo)致生產(chǎn)成本高,開(kāi)發(fā)周期長(zhǎng)。電機(jī)設(shè)計(jì)有超過(guò)25個(gè)不同的部分。組裝各個(gè)部分的緊固件,軸承,連接器不是一項(xiàng)容易的任務(wù)。三曲柄的應(yīng)用機(jī)制產(chǎn)生行星運(yùn)動(dòng)需要精確的制造和裝配。否則,它更有可能導(dǎo)致移動(dòng)部件之間的干擾,從而導(dǎo)致發(fā)動(dòng)機(jī)故障。