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精选优质文档-倾情为你奉上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 robots 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 peoples 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.专心-专注-专业
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