鍛壓機(jī)自動上料機(jī)械手執(zhí)行系統(tǒng)設(shè)計
鍛壓機(jī)自動上料機(jī)械手執(zhí)行系統(tǒng)設(shè)計,鍛壓機(jī)自動上料機(jī)械手執(zhí)行系統(tǒng)設(shè)計,鍛壓,自動,機(jī)械手,執(zhí)行,履行,系統(tǒng),設(shè)計
Industrial Robots and Electric drive system
There are a variety of definitions of the term robot. Depending on the definition used, the number of robot installations worldwide varies widely. Numerous single-purpose machines are used in manufacturing plants that might appear to be robots. These machines are hardwired to perform a single function and cannot be reprogrammed to perform a different function. Such single-purpose machines do not fit the definition for industrial robots that is becoming widely accepted. This definition was developed by the Robot Institute of America:
A robot is a reprogrammable multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks.
Note that this definition contains the words reprogrammable and multifunctional. It is these two characteristics that separate the true industrial robot from the various single-purpose machines used in modern manufacturing firms. The term “reprogrammable” implies two things: The robot operates accommodate a variety of manufacturing tasks.
The term “multifunctional” means that the robot can, through reprogramming and the use of different end-effectors, perform a number of different manufacturing tasks. Definitions written around these two critical characteristics are becoming the accepted definitions among manufacturing professionals.
The first articulated arm came about in 1951 and was used by the U.S. Atomic Energy Commission. In 1954, the first programmable robot was designed by George Devil. It was based on two important technologies:
Numerical control (NC) technology.
Remote manipulator technology.
Numerical control technology provided a form of machine control ideally suited to robots. It allowed for the control of motion by stored programs. These programs contain data points to which the robot sequentially moves, timing signals to initiate action and to stop movement, and logic statements to allow for decision making.
Remote manipulator technology allowed a machine to be more than just another NC machine. It allowed such machines to become robots that can perform a variety of manufacturing tasks in both inaccessible and unsafe environments. By merging these two technologies, Devil developed the first industrial robot, an unsophisticated programmable materials handling machine.
The first commercially produced robot was developed in 1959. In 1962, the first industrial robot to be used on a production line was installed by General Motors Corporation. This robot was produced by Animation. A major step forward in robot control occurred in 1973 with the development of the T-3 industrial robot by Cincinnati Milacron. The T-3 robot was the first commercially produced industrial robot controlled by a minicomputer.
Numerical control and remote manipulator technology prompted the wide-scale development and use of industrial roots. But major technological developments do not take place simply because of such new capabilities. Something must provide the impetus for taking advantage of these capabilities. In the case of industrial robots, the impetus was economics.
The rapid inflation of wages experienced in the 1970s tremendously increased the personnel costs of manufacturing firms. At the same time, foreign competition became a serious problem for U.S. manufacturers. Foreign manufacturers who had undertaken automation on a wide-scale basis, such as those in Japan, began to gain an increasingly large share of the U.S. and world market for manufactured goods, particularly automobiles.
Through a variety of automation techniques, including robots, Japanese manufacturers, beginning in the 1970s, were able to produce better automobiles more cheaply than no automated U.S. manufacturers. Consequently, in order to survive, U.S. manufacturers were forced to consider any technological developments that could help improve productivity.
Though a variety of automation techniques, including robots, Japanese manufacturers, beginning in the 1970s, were able to produce better automobiles more cheaply than no automated U.S. manufacturers. Consequently, in order to survive, U.S. manufacturers were forced to consider any technological developments that could help improve productivity.
It became imperative to produce better products at lower costs in order to be competitive with foreign manufacturers. Other factors such as the need to find better ways of performing dangerous manufacturing tasks contributed to the development of industrial robots. However, the principal rationale has always been, and is still, improved productivity.
One of the principal advantages of robots is that they can be used in settings that are dangerous to humans. Welding and parting are examples of applications where robots can be used more safely than humans, Even though robots are closely associated with safety in the workplace, they can, in themselves, be dangerous.
Robots and robot cells must be carefully designed and configured so that they do not endanger human workers and other machines. Robot work envelopes should be accurately calculated and a danger zone surrounding the envelope clearly marked off. Red flooring strips and barriers can be used to keep human workers out of a robot’s work envelope.
Even with such precautions it is still a good idea to have an automatic shutdown system in situations where robots are used. Such a system should have the capacity to sense the need for an automatic shutdown of operations. Fault-tolerant computers and redundant systems can be installed to ensure proper shutdown of robotics systems to ensure a safe environment.
The robot electrically operated servo drive system sds is uses the moment of force and the strength which each kind of electric motor produces, directly or indirectly actuates the robot main body to obtain the robot each kind of movement implementing agency. The electric motor actuates which to the industry robot joint, the request has the maximum work rate quality compared to with the torque inertia compared to, rises up the dynamic torque, the is low inertia and broader also the smooth velocity modulation scope. Specially (hand fingernail) should use the volume, the quality as far as possible small electric motor like the robot terminal execution, when in particular requests the fast response, the servo motor must have a higher reliability and the stability, and has the bigger momentary overload ability. This is the servo motor in the industry robot the application precondition.
The robot actuates the electrical machinery to the joint overriding demand the gauge natrium as follows:
1) rapidity. The electric motor from obtains the command signal to complete the active status time which the instruction requests to be supposed to be short. Response command signal time shorter, the electricity servosystem sensitivity higher, the fast response performance is better, generally is explains the servo motor fast response by the servo motor mechanical and electrical time-constant size the performance.
2) the starting moment inertia is bigger than. In in the actuation load situation, requests the robot the servo motor starting moment in a big way, the rotation inertia is small.
3) the control characteristic continuity and the straight line, along with the control signal change, the electric motor rotational speed can continuously change, sometimes also needs the rotational speed and the control signal has the direct ratio or approximately has the direct ratio.
4) modulates velocity the scope to be wide. Can use to 1: 1,000 ~ 10,000 velocity modulation scopes.
5)the volume small, the quality small, the axial size is short.
6) can undergo the harsh movement condition, may carry on the extremely frequent pro and con to and adds and subtracts the fast movement, and can withstand the overload in the short time.
Industry robot direct motor drive principle like chart 1 shows. The industry robot electrically operated servosystem general structure is three closed-loops control, namely electric current link, speed ring and snap ring.
At present the overseas many electric motors produce the factory to develop the actuation product which suitably matches with the exchange servo motor, the user act according to oneself need the function stress to choose the different servo-control way differently, in the ordinary circumstances, exchanges the servo driver below, passable has carried on the artificial hypothesis to its internal function parameter to realize the function:
1) position control way;
2) speed control way;
3) torque control mode;
4) position, speed mixed mode;
5) position, torque mixed mode;
6)speed, torque mixed mode;
7) torque limitation;
8) the position deviation oversized reports to the police;
9) speed PID parameter establishment;
10) speed and acceleration forward feed parameter establishment;
11) zero floats compensates the parameter establishment;
12) adds and subtracts the fast time establishment and so on
1. direct current servo motor driver direct current servo motor driver to use the pulse-duration modulation (PWM) the servo driver, changes through the change pulse width adds in the motor armature beginnings and ends average voltage, thus changes the electric motor the rotational speed. The PWM servo driver has the velocity modulation scope width, the low-speed characteristic well, responds, the efficiency quickly high, the overload capacity is strong and so on the characteristic, often takes the direct current servo motor driver in the industry robot.
2. synchronized types exchange servo motor driver same direct current servo motor actuates the system to compare, the synchronized type exchange servo motor driver has the torque rotation inertia electronics brush and commutation spark merit and so on to be higher than, not to have, obtains the widespread application in the industry robot. The synchronized type exchange servo motor driver usually uses the electricity flow pattern pulse-duration modulation (PWM) the inversion and has the electric current link for the inner rim, the speed ring for the outer ring multi- closed-loop control system, realizes to the three-phase permanent magnetism synchronization servo motor electric current control. According to its principle of work, the actuation current waveform and the control mode difference, it may divide into two kind of servosystems:
1) rectangular wave electric current actuation permanent magnetism A.C. servomechanism.
2) sinusoidal current actuation permanent magnetism A.C. servomechanism. Uses the rectangular wave electric current actuation the permanent magnetism exchange servo motor to be called not brushes the direct current servo motor, uses he sinusoidal current actuation the permanent magnetism exchange servo motor to be called not brushes the exchange servo motor.
3. direct drives so-called direct drives (DD) the system, is the load conductive coupling which the electric motor if actuates in the same place, middle does not have any reduction gear. The same traditional electric motor servo actuates to compare, the DD actuation reduced the reduction gear, thus reduced the gap which in the system transmission process the reduction gear produces and becomes less crowded, enormously increased the robot precision, simultaneously also reduced because the reduction gear friction and the transmission torque pulsation creates the robot control precision reduces. But DD actuation because has above merit, therefore mechanical rigidity good, may the high speed high accuracy movement, also has the part few, the structure simple, is easy to service, the reliable higher characteristic, in the high accuracy, in the high speed industry robot application more and more brings to people's attention. As the DD actuation technology essential link is the DD electric motor and its the driver. Below it should have the characteristic:
1) outputs the torque in a big way: For tradition drive type in servo motor output torque 50 ~ 100 times.
2) torque pulsation small: The DD electric motor torque pulsation may suppress in the output torque 5% ~ in 10%.
3) efficiency: With uses the reasonable impedance matching the electric motor (under tradition drive type) to compare, the DD electric motor is works under the power conversion worse exploitation conditions. Therefore, the load is bigger, more favors to selects a bigger electric motor.
At present, the DD electric motor mainly divides into changes the magnetic resistance and changes the magnetic resistance mixed type, has following two kind of structures pattern:
1) the double stator structure changes the magnetic resistance DD electric motor;
2) the central stator structure changes the magnetic resistance mixed type DD electric motor.
5. special drivers
1)piezoelectricity driver. It is well known, has made using the piezoelectricity part electricity or the electrostriction phenomenon should the variant acceleration instrument and the ultrasonic sensor, the piezoelectricity driver use the site of electrical energy controls several microns to several hundred microns displacements in is higher than the micron level big strength, therefore the piezoelectricity driver generally uses in the special use miniature robot assembly system.
2) ultrasonic wave electric motor.
3) the vacuum electric motor, uses in the vacuum robot which under the ultra pure environment works, for example uses in to transport the semiconductor silicon chip the ultra vacuum robot and so on.
工業(yè)機(jī)器人及電動驅(qū)動系統(tǒng)
有許多關(guān)于機(jī)器人這個術(shù)語的定義。采用不同的定義,全世界各地機(jī)器人的數(shù)量就會發(fā)生很大的變化。 在制造工廠中使用的許多單用途機(jī)器可能會看起來像機(jī)器人。這些機(jī)器是硬連線的,不能通過重新編程的方式去完成不同的工作。這種單用途的機(jī)器不能滿足人們?nèi)找鎻V泛接受的關(guān)于工業(yè)機(jī)器人的定義。這個定義是由美國機(jī)器人協(xié)會提出的:
機(jī)器人是一個可以改變程序的多功能操作器,被設(shè)計用來按照預(yù)先編制的、能夠完成多種作業(yè)的運動程序運送材料、零件、工具或者專用設(shè)備。
注意在這個定義中包含有“可以改變程序”和“多功能”這兩個詞。正是這兩個詞將真正的機(jī)器人與現(xiàn)代制造工廠中使用的單一用途的機(jī)器區(qū)分開來?!翱梢愿木幊绦颉边@個術(shù)語意味著兩件事:機(jī)器人根據(jù)編寫的程序工作,以及可以通過重新編寫程序來適應(yīng)不同種類的制造工作的需要。
“多功能”這個詞意味著機(jī)器人能通過編程和使用不同的末端執(zhí)行機(jī)構(gòu),來完成不同的制造工作。圍繞著這兩個關(guān)鍵特征所撰寫的定義正在變成為制造業(yè)的專業(yè)人員所接受的定義。
第一個帶有活動關(guān)節(jié)的手臂于1951年被研制出來,由美國原子能委員會使用。在1954年,第一個可以編程的機(jī)器人有喬治.狄弗設(shè)計出來。它基于下面兩項重要技術(shù):
數(shù)字控制(NC)技術(shù)。
遠(yuǎn)程操作器技術(shù)。
數(shù)字控制技術(shù)提供了一種非常適合于機(jī)器人的機(jī)器控制技術(shù)。它可以通過儲存的程序?qū)\動進(jìn)行控制。這些程序包含機(jī)器人進(jìn)行順序運動的數(shù)據(jù),開始運動和停止運動的時間控制信號,以及做出決定所需要的邏輯語句。
遠(yuǎn)程操作器技術(shù)使得一臺機(jī)器的性能超出一臺數(shù)控機(jī)器。它可以使這種機(jī)器能夠在不容易進(jìn)入和不安全的環(huán)境中完成各種制造任務(wù)。通過融合了上述兩項技術(shù),狄弗研制出第一個機(jī)器人,它是一個不復(fù)雜的,可以編程的物料運送機(jī)器人。
第一臺商業(yè)化生產(chǎn)的機(jī)器人在1959年研制成功。通用汽車公司在1962年安裝了第一臺用于生產(chǎn)線上的工業(yè)機(jī)器人,它是尤尼梅森公司生產(chǎn)的。在1973年,辛辛那提.米蘭克朗公司研制出T-3工業(yè)機(jī)器人,在機(jī)器人的控制方面取得了較大的進(jìn)展。T-3機(jī)器人是第一臺商業(yè)化生產(chǎn)的采用計算機(jī)控制的機(jī)器人。
數(shù)字控制技術(shù)和遠(yuǎn)程操作器技術(shù)推動了大范圍的機(jī)器人研制和應(yīng)用。但是主要的技術(shù)進(jìn)步并不僅僅上由于這些新的應(yīng)用能力而產(chǎn)生的,而是必須由利用這些能力所得到的效益來提供動力。就工業(yè)機(jī)器人而言,這個動力是經(jīng)濟(jì)性。
在20世紀(jì)70年代中,工資的快速增長大大增加了制造業(yè)的企業(yè)中的人工費用。與此同時,來自國外的競爭成為美國制造業(yè)所面臨的一個嚴(yán)峻的考驗。諸如日本等外國的制造廠家在廣泛地應(yīng)用了自動化技術(shù)之后,其工業(yè)產(chǎn)品,特別是汽車,在美國和世界時常中占據(jù)了日益增大的分額。
通過采用包括機(jī)器人在內(nèi)的各種自動化技術(shù),從70年代開始,日本的制造廠家能夠比沒有采用自動化技術(shù)的美國制造廠家生產(chǎn)更好的和更便宜的汽車。隨后,為了生存,美國制造廠家被迫考慮采用任何能夠提高生產(chǎn)率的技術(shù)。
為了與國外制造廠家進(jìn)行競爭,必須以比較低的成本,生產(chǎn)出更好的產(chǎn)品。其他的因素,諸如尋找能夠更好地完成帶有危險性的制造工作的方式也促進(jìn)了工業(yè)機(jī)器人的發(fā)展。但是,主要的理由一直是,而且現(xiàn)在仍然是提高生產(chǎn)率。
機(jī)器人的一個主要優(yōu)點是它們可以在對于人類來說是危險的位置上工作。采用機(jī)器人進(jìn)行焊接和切斷工作上比由人工來完成這些工作更安全的例子。盡管機(jī)器人與工作地點的安全密切相關(guān),它們本身也可能是危險的。
應(yīng)該仔細(xì)地設(shè)計和配置機(jī)器人和機(jī)器人單元,使它們不會傷害人類和其他機(jī)器。應(yīng)該精確地計算出機(jī)器人的工作范圍,并且在這個范圍的四周清楚地標(biāo)出危險區(qū)域??梢圆捎迷诘孛嫔袭嫵黾t顏色的線和設(shè)置障礙物以阻止工人進(jìn)入機(jī)器人的工作范圍。
即使有了這些預(yù)防措施,在使用機(jī)器人的場地中設(shè)置一個自動停止工作的系統(tǒng)仍然上不失為一個好主意。機(jī)器人的這個系統(tǒng)應(yīng)該具有能夠檢測出是否有需要自動停止工作的要求的能力。為了保證能有一個安全的環(huán)境,應(yīng)當(dāng)安裝容錯計算機(jī)和冗余系統(tǒng)來保證在適當(dāng)?shù)臅r候停止機(jī)器人的工作。
機(jī)器人電動伺服驅(qū)動系統(tǒng)是利用各種電動機(jī)產(chǎn)生的力矩和力,直接或間接地驅(qū)動機(jī)器人本體以獲得機(jī)器人的各種運動的執(zhí)行機(jī)構(gòu)。
對工業(yè)機(jī)器人關(guān)節(jié)驅(qū)動的電動機(jī),要求有最大功率質(zhì)量比和扭矩慣量比、高起動轉(zhuǎn)矩、低慣量和較寬廣且平滑的調(diào)速范圍。特別是像機(jī)器人末端執(zhí)行器(手爪)應(yīng)采用體積、質(zhì)量盡可能小的電動機(jī),尤其是要求快速響應(yīng)時,伺服電動機(jī)必須具有較高的可靠性和穩(wěn)定性,并且具有較大的短時過載能力。這是伺服電動機(jī)在工業(yè)機(jī)器人中應(yīng)用的先決條件。
機(jī)器人對關(guān)節(jié)驅(qū)動電機(jī)的主要要求規(guī)納如下:
1)快速性。電動機(jī)從獲得指令信號到完成指令所要求的工作狀態(tài)的時間應(yīng)短。響應(yīng)指令信號的時間愈短,電伺服系統(tǒng)的靈敏性愈高,快速響應(yīng)性能愈好,一般是以伺服電動機(jī)的機(jī)電時間常數(shù)的大小來說明伺服電動機(jī)快速響應(yīng)的性能。
2)起動轉(zhuǎn)矩慣量比大。在驅(qū)動負(fù)載的情況下,要求機(jī)器人的伺服電動機(jī)的起動轉(zhuǎn)矩大,轉(zhuǎn)動慣量小。
3)控制特性的連續(xù)性和直線性,隨著控制信號的變化,電動機(jī)的轉(zhuǎn)速能連續(xù)變化,有時還需轉(zhuǎn)速與控制信號成正比或近似成正比。
4)調(diào)速范圍寬。能使用于1:1000~10000的調(diào)速范圍。
5)體積小、質(zhì)量小、軸向尺寸短。
6)能經(jīng)受得起苛刻的運行條件,可進(jìn)行十分頻繁的正反向和加減速運行,并能在短時間內(nèi)承受過載。
工業(yè)機(jī)器人電動伺服系統(tǒng)的一般結(jié)構(gòu)為三個閉環(huán)控制,即電流環(huán)、速度環(huán)和位置環(huán)。
目前國外許多電動機(jī)生產(chǎn)廠家均開發(fā)出與交流伺服電動機(jī)相適配的驅(qū)動產(chǎn)品,用戶根據(jù)自己所需功能側(cè)重不同而選擇不同的伺服控制方式,一般情況下,交流伺服驅(qū)動器,可通過對其內(nèi)部功能參數(shù)進(jìn)行人工設(shè)定而實現(xiàn)以下功能:
1)位置控制方式
2)速度控制方式;
3)轉(zhuǎn)矩控制方式;
4)位置、速度混合方式;
5)位置、轉(zhuǎn)矩混合方式;
6)速度、轉(zhuǎn)矩混合方式;
7)轉(zhuǎn)矩限制;
8)位置偏差過大報警;
9)速度PID參數(shù)設(shè)置;
10)速度及加速度前饋參數(shù)設(shè)置;
11)零漂補償參數(shù)設(shè)置;
12)加減速時間設(shè)置等
1.直流伺服電動機(jī)驅(qū)動器
直流伺服電動機(jī)驅(qū)動器多采用脈寬調(diào)制(PWM)伺服驅(qū)動器,通過改變脈沖寬度來改變加在電動機(jī)電樞兩端的平均電壓,從而改變電動機(jī)的轉(zhuǎn)速。
PWM伺服驅(qū)動器具有調(diào)速范圍寬、低速特性好、響應(yīng)快、效率高、過載能力強(qiáng)等特點,在工業(yè)機(jī)器人中常作為直流伺服電動機(jī)驅(qū)動器。
2.同步式交流伺服電動機(jī)驅(qū)動器
伺服電動機(jī)驅(qū)動系統(tǒng)相比,同步式交流伺服電動機(jī)驅(qū)動器具有轉(zhuǎn)矩轉(zhuǎn)動慣量比高、無電刷及換向火花等優(yōu)點,在工業(yè)機(jī)器人中得到廣泛應(yīng)用。
同步式交流伺服電動機(jī)驅(qū)動器通常采用電流型脈寬調(diào)制(PWM)相逆變器和具有電流環(huán)為內(nèi)環(huán)、速度環(huán)為外環(huán)的多閉環(huán)控制系統(tǒng),以實現(xiàn)對三相永磁同步伺服電動機(jī)的電流控制。根據(jù)其工作原理、驅(qū)動電流波形和控制方式的不同,它又可分為兩種伺服系統(tǒng):
1)矩形波電流驅(qū)動的永磁交流伺服系統(tǒng)。
2)正弦波電流驅(qū)動的永磁交流伺服系統(tǒng)。
矩形波電流驅(qū)動的永磁交流伺服電動機(jī)稱為無刷直流伺服電動機(jī),采用正弦波電流驅(qū)動的永磁交流伺服電動機(jī)稱為無刷交流伺服電動機(jī)。
3.直接驅(qū)動
驅(qū)動(DD)系統(tǒng),就是電動機(jī)與其所驅(qū)動的負(fù)載直接耦合在一起,中間不存在任何減速機(jī)構(gòu)。
同傳統(tǒng)的電動機(jī)伺服驅(qū)動相比, DD驅(qū)動減少了減速機(jī)構(gòu),從而減少了系統(tǒng)傳動過程中減速機(jī)構(gòu)所產(chǎn)生的間隙和松動,極大地提高了機(jī)器人的精度,同時也減少了由于減速機(jī)構(gòu)的摩擦及傳送轉(zhuǎn)矩脈動所造成的機(jī)器人控制精度降低。而DD驅(qū)動由于具有上述優(yōu)點,所以機(jī)械剛性好,可以高速高精度動作,且具有部件少、結(jié)構(gòu)簡單、容易維修、可靠性高等特點,在高精度、高速工業(yè)機(jī)器人應(yīng)用中越來越引起人們的重視。
作為DD驅(qū)動技術(shù)的關(guān)鍵環(huán)節(jié)是DD電動機(jī)及其驅(qū)動器。它應(yīng)具有以下特性:
1)輸出轉(zhuǎn)矩大:為傳統(tǒng)驅(qū)動方式中伺服電動機(jī)輸出轉(zhuǎn)矩的50~100倍。
2)轉(zhuǎn)矩脈動?。?DD電動機(jī)的轉(zhuǎn)矩脈動可抑制在輸出轉(zhuǎn)矩的5%~10%以內(nèi)。
3)效率:與采用合理阻抗匹配的電動機(jī)(傳統(tǒng)驅(qū)動方式下)相比, DD電動機(jī)是在功率轉(zhuǎn)換較差的使用條件下工作的。因此,負(fù)載越大,越傾向于選用較大的電動機(jī)。
目前,DD電動機(jī)主要分為變磁阻型和變磁阻混合型,有以下兩種結(jié)構(gòu)型式:
l)雙定子結(jié)構(gòu)變磁阻型DD電動機(jī);
2)中央定子型結(jié)構(gòu)的變磁阻混合型DD電動機(jī)。
5.特種驅(qū)動器
1)壓電驅(qū)動器。眾所周知,利用壓電元件的電或電致伸縮現(xiàn)象已制造出應(yīng)變式加速度傳感器和超聲波傳感器,壓電驅(qū)動器利用電場能把幾微米到幾百微米的位移控制在高于微米級大的力,所以壓電驅(qū)動器一般用于特殊用途的微型機(jī)器人系統(tǒng)中。
2)超聲波電動機(jī)。
3)真空電動機(jī),用于超潔凈環(huán)境下工作的真空機(jī)器人,例如用于搬運半導(dǎo)體硅片的超真空機(jī)器人等。
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