Now electrical automation has been applied to the field of robots. The following is my thesis about electric automation robot. Welcome to read the reference!
Abstract: With the development trend of economic globalization and modernization, industrial equipment is becoming more and more intelligent and automated. Automation industry is to popularize welding robots. In order to improve the welding quality and work efficiency, improve the labor intensity and working environment of workers, actively reduce the traditional operation process, change the production process, shorten the production cycle of products and save costs.
Keywords: electrical automation; Robots; Matching welding; work station
In the process of industrial modernization and inter-factory automation development, only by combining the welding positioner with the welding robot can the fully automatic operation of the welding robot be guaranteed. At the same time, welding in automobile, electronics and other fields can also reduce the disadvantages brought by traditional manual operation. Thereby further improving the product quality and production efficiency and the assembly line operation level between factories.
1 technical scheme
Welding robot belongs to modern products in industrial robots. Multi-purpose operation can be realized. Among them, repetitive programmable automatic control equipment promotes the wide application of welding robots in the field of industrial automation. Flexibility means that the automatic operation of CNC machine tools and equipment is controlled by information technology such as computer system or material storage and transportation system. The so-called robot flexible welding workstation is controlled by computer information control system, and the welding robot is combined with welding positioner to realize auto production line operation. This small operation process can weld all kinds of products with workpiece standards below 2.5 meters. It not only integrates the application functions of automatic feeding, semi-automatic positioning and clamping, automatic welding and automatic unloading in equipment operation, but also adopts a unified assembly line technical scheme, which consists of workpiece positioning fixture, intelligent carrier, positioner, component turnover frame, palletizing frame and feeding mechanism, in which electrical and pneumatic systems are used as production procedures. From the two-way innovation of equipment and procedures, we can improve production efficiency and reduce work intensity.
The system uses special shielded cable to connect Siemens S7-300, S7-200, ET200, robot adapter card, touch screen and other control devices, forming a network design scheme of PROFIBUS-DP communication link. In the later stage, the network communication status is monitored and processed in real time to avoid downtime caused by communication failure.
2. The design of locator
The locator is special. Welding auxiliary equipment. The working principle is applied to welding displacement in rotating work, and the accuracy of machining position and welding speed is realized again. It has two systems: turning and turning. Through the lifting and turning of the workbench, it can complete the automatic operation of angle assembly and stepless speed regulation, and can be used in conjunction with welding machines and manipulators to form an automatic welding center. The welder of the workbench requires high accuracy and time efficiency, which is a difficult problem for manual operation. The rotary application of positioner brings stepless speed regulation of frequency converter with high speed regulation accuracy and remote control box equipment that can complete remote operation of workbench to welding equipment. The design of these positioner not only connects the manipulator with the operating system of the welding machine, but also realizes the linkage operation of the whole welding work and achieves the ideal welding speed.
The locator mentioned here belongs to the core component of the robot flexible welding workstation. Including steel structure, rotating shaft, turnover shaft, guide rail, quick snap ring and other workpiece equipment, each with different functions. The precision of positioner determines the welding effect of robot flexible welding workstation. If the welding accuracy of the robot flexible welding workstation is less than 0.5 mm, it is required that the positioner must take the turntable with a diameter of 3.8 meters as the core equipment, and the positioning accuracy and overturning positioning accuracy of rotating it 180 degrees should be less than 0.5 mm.
3 design of intelligent carrier
Intelligent truck refers to the unloading machinery that uses motor equipment to realize the lifting and transverse movement of goods. include
Lifting frame, transverse frame, guide sleeve, transverse wheel, telescopic fork arm and other main components. Its main function in the robot flexible welding workstation is to improve the stacking efficiency, and use the guide rail to transport the workpiece clamped by the welding positioner to the designated stacking frame. The use of intelligent carrier constitutes the operation of automatic production line, which greatly reduces the labor intensity and improves the overall production efficiency.
4 Design of workpiece positioning fixture
Workpiece positioning fixture means that in order to realize the rapid clamping of different workpieces, the spring of the air cylinder and the hook or quick snap ring of the positioner are used to simultaneously realize the positioning and clamping of workpieces. The positioner is installed on the universal fixture bracket, and the positioner is used to realize the quick connection between the positioner and the workpiece positioning fixture.
5 robot action design
As the protagonist of the flexible welding workstation, the installation position of the robot is particularly important, and it is located by computer simulation. According to the actual working situation, with the cooperation of other linkage equipment, after repeated teaching on site, the robot's movements, postures, trajectories and speeds gradually reached high-speed coordination and unification, and finally met the design requirements of the system's working rhythm and operating accuracy.
6 control system design
The control system not only semantically integrates the main automatic control elements such as man-machine interface, servo closed-loop drive and PLC positioning module, but also ensures the accuracy and maintainability during operation.
6. 1PLC master control and robot controller signal
(1) robot position information
When it returns to the origin or enters the non-interference zone, the welding robot will send a signal to inform the PLC master controller. The welding robot will complete the signal interlocking and the use of control points in the first time. For example, in the welding process, in order to avoid the collision accident caused by the accidental turntable of the welding robot, PLC will strictly shield the turntable rotation and fixture action.
(2) Description of fixture control
Fixture control instruction refers to the control instruction that the welding robot may not be able to weld some solder joints in the welding work, and it is necessary to repair the welding operation of a clamping unit or control the rotation of the fixture when designing the fixture, so as to promote the welding robot to weld completely. The welding robot sends instructions to the fixture control in the middle of welding and transmits them to the fixture control unit through the bus, so as to keep the repair welding work of the fixture unit started in time during the repair welding operation, ensure the system operation and avoid mistakes.
(3) System signal
System signal means that it can be displayed on the touch screen of the system through PLC master control. This is conducive to the supervision and inquiry behavior of operators. Including system initialization information, fault information, program execution progress, etc.
6.2PLC main control and welding fixture control unit signal
The welding fixture is provided with a fixture control unit. The fixing device consists of ET200 bus terminal, I/O terminal and bus power supply. The working principle is that the input and output signals on the fixture, including the workpiece arrival signal, the cylinder clamping opening signal and the fixture operation button, must be connected to the I/O terminal, and then the I/O signal is converted into a bus signal through the ET200M bus terminal, which is transmitted to the PLC main control system in a bus way to complete the control instruction for the fixture.
6.3PLC master control and touch screen signal
Selection and display of production products
The workstation is equipped with a touch screen. Touch screen displays control instructions. When the product needs to be replaced, the product type can be selected on the touch screen before production, and the system execution button can be determined when it is consistent with the system identification fixture. Otherwise, there will be early warning information to ensure the accuracy of production. Among them, the production information such as the type of products produced and the selection of the working state of the robot can be operated according to the display on the homepage of the touch screen.
Manual control and its fault handling
Touch screen operation display can realize independent control of all input and output points of the workstation. This simple and easy-to-operate manual system realizes integrated debugging, maintenance and fault handling. Through the automatic query function of the system, the control points with logical relationship are ensured to act. When the system has early warning and fault, you can check the fault information according to the pop-up window, and the system will put forward treatment suggestions. When the fault is eliminated, manual operation is needed to complete the reset behavior to ensure that the fault is handled.
7 safety loop design
The security configuration of workstations is particularly important. In the actual design, the safety loops of robots, area gratings, control systems, field operations and other equipment should be integrated into a whole, and wiring and programming should be carried out according to the dual locking mode of hardware and software, so that when there is a problem at the safety monitoring point, the related moving equipment can be stopped immediately and reliably, and an audible and visual alarm can be given in time, and the reasons for the safety alarm can be displayed on the touch screen.
label
Starting with the technical scheme of robot flexible welding workstation, this paper briefly discusses the specific design of key components of welding robot system such as positioner, intelligent carrier, robot body and workpiece positioning. It not only shows that this design scheme has far-reaching influence on solving the problems of positioner accuracy, communication, carrier picking and placing and robot action, but also gives a reasonable explanation to the technical problems of rapid positioning and clamping of workpieces.
References:
[1] Wu. Analysis of intelligent robot welding technology [J] Journal of Langfang Teachers College (Natural Science Edition), 2008( 10)
Li Xiaohui, Wang Su. Intelligent development of welding robot [J]. Electric welding machine, 2005(06)
Huo Wenfeng. Flexible control system of welding robot based on PLC [J]. Agricultural Network Information, 20 12(07)
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