Robot-based curve welding system

At present, most of the small workpieces with curved structure Sierra Leone Sugar mostly use manual welding methods, which require high skills and labor intensity of the welder. In large cases, the quality of welding tools is difficult to guarantee. Therefore, it is very necessary to introduce welding automation equipment, and welding robots and welding machines are two important ways to realize welding automation. The special welding machine is a special equipment designed for the welding of one or several workpieces. It has no obvious advantages in welding small workpieces with curved structures; while the welding robot is a flexible welding equipment that can achieve curved structures by changing the programSierra Leoneans SugardaddyWelding of small workpieces[. With Sierra Leone Sugar with the continuous development of computer technology, information control technology and artificial intelligence technology, more and more robots are used Giving birth to children in the industry not only ensures the quality of welding tools but also reduces the labor intensity of workers and the cost of giving birth. For the welding of complex workpieces, due to the limitations of the welding robot’s arm length and unrestrained degree, it is difficult for the welding gun to reach certain welds. A welding positioner is required to pull the workpiece apart so that the corresponding welds are in the ideal welding position to facilitate the machine. People perform welding operations. This research Sierra Leoneans Escort designed a robot-based curve welding system, using a combination of robots and PLC to control the rotation and flipping of the positioner , so that the curved seam to be welded is in the best welding position, and then the robot starts welding automatically.
1 Overall design of the system The arc-shaped structural member is shown in Figure 1, which is a type of curved structural member. It has 4 arc welds on different surfaces (semi-Sierra Leoneans EscortV groove). In order to facilitate robot welding, it adopts The baseSierra Leoneans Escort type positioner adjusts the spatial position of the weld. SL EscortsIn order to improve the efficiency of welding to have children, set up 3Sierra Leoneans Sugardaddy stations. Station 1 and station 3 are fixed stations, both operated by Sierra Leone Sugar Daddy is composed of a flexible platform, used for the assembly of curvedSierra Leone Sugar linear structural components; Position 2 consists of a positioner, which is used for welding curved structure workpieces. Simply change the welding tooling or fixture and change the robot program. The workstation layout is shown in Figure 2.
2 Electrical. Control system design The welding system consists of the KUKA robot body, robot controller, welding machine, PLC, touch screen, contact sensor and arc sensor. The frame is shown in Figure 3. The touch screen of Siemens TP700 Comfort is used as the human-computer interaction interface. , through Sierra Leone SugarCheng DSierra Leone SugareviceNet bus realizes real-time communication between the robot and the welding machine, and the displacement is jointly controlled by the PLC and the robot. The machine turns and rotates to ensure that the welding seam is in a flat welding position or a ship-shaped welding position. Consider the welding characteristics and production of curved structure workpieces. Cost, use PLC to control the turning of the positioner, and change the turning speed of the positioner by controlling the input frequency of the frequency converter. The turning control method of the positioner is divided into two types: manual and automatic control. In order to make the space complex curve welding. The seam is always in the best welding position, and the positioner and the robot need to move synchronously and harmoniously during the welding process. That is, the positioner needs to keep rotating during the welding process to keep the weld seam in the best welding position. At the same time, the machine The person adjusts the position and posture of the welding gun to weld the weld seam. In order to facilitate workers’ on-site operation, tracking movement control is set on the teaching function, that is, when the positioner moves, the robot follows the movement and maintains a relative relationship with the positioner. .Through teaching control of internal axes and robotsThrough the teaching control, the internal axis action program 1 and the robot action program 2 are generated. Activate French 1 and French 2 SL Escorts at the same time to achieve harmonious movement of the robot and the internal axis. 3 System control process Geometric dimensions and position errors as well as deformation caused by heating of the workpiece during the welding process will cause the actual weld position to deviate from the teaching trajectory. In order to ensure the reliability of the quality of welding tools, the system uses contact sensors and arc sensors for accurate positioning and real-time modification of the teaching trajectory. The working principle of the contact sensor is shown in Figure 4. When the welding wire does not contact the position of the workpiece to be inspected, Sierra Leone Sugar weldingSierra Leone Sugar DaddyCircuit A consisting of power supply, relay wire and workpiece is in a disconnected state, the relay is not energized, and the mechanical Circuit B connecting the DC power supply in the Sierra Leone Sugar Daddy control cabinet to the normally open contact of the relay is also not connected. When the welding wire comes into contact with the workpiece to be detected and a short circuit occurs, circuit A is closed to energize the relay, and its normally open contact is closed, causing circuit B to be connected to generate a voltage electronic signal. The robot control cabinet detects this voltage electronic signal. At this time, record the spatial position and angle of the welding gun. When teaching, first bring the welding wire into contact with the designated welding starting point on the workpiece, and the robot control system records this starting position as the reference position through the contact sensing function. In actual welding, when looking for the starting position of the corresponding weld seam, the contact sensor detects a new position, and the robot control system compares this position with the reference position to obtain the error amount, and then calculates the compensation amount based on the error amount, and The amount of compensation is reflected in the actual welding starting position. During the welding process, uneven heating of the workpiece causes thermal deformation, causing the teaching trajectory to deviate from the actual position of the weld. This seminar SL Escorts uses KUKA Arc Sense manifold box Basic to modify the welding trajectory. The diverter box contains arc sensors that Sierra Leoneans Sugardaddy rely on during swing welding.Find the center of the weld according to the change in the welding current response value, and modify the teaching trajectory error in real time. Since the length of the welding arc is inversely proportional to the dry elongation of the welding wire, and the dry elongation of the welding wire Sierra Leoneans Escort is directly proportional to the current, therefore, the welding current The change of can reflect the offset between the swing center and the groove center, as shown in Figure 5. If the actual welding seam position does not deviate from the teaching trajectory, the welding current when the welding gun swings to the left and right limit positions is the same, and there is no need to modify the robot teaching trajectory; if the actual welding seam position tilts to the left of the teaching trajectory, the welding current at the left extreme position becomes larger, this time the robot trajectory Sierra Leone Sugar needs to be modified to the right; if the actual weld position tends to the right side of the teaching trajectory, Then the welding current at the extreme position on the right side becomes larger, and at this time the robot trajectory needs to be modified to the left. When teaching, first turn on the main power supply to power up the robot. After the system initialization is completed, select the SL Escorts teaching mode, and then Sierra Leone Sugar Daddy and then create a new program and select the appropriate coordinate system according to Sierra Leone Sugar Teaching criteria, for arc welds, 3 attribute points are usually required to determine the teaching trajectory using arc interpolation method, as shown in Figure 6. Use the contact sensor to find the starting point P1, the center point P2 and the stop point P3 of the weld, and then use the arc interpolation method to determine the weld SL EscortsStatus. Through the flipping and rotating of the positioner, each welding seam is Sierra Leoneans Escort in the best welding position, and then follow the above method Complete the teaching of all welds. The teaching process is shown in Figure 7. After completing the assembly task of station 2, call up the welding program corresponding to the workpiece through the teaching pendant, press the start button, the robot finds the welding start point through the contact sensor, and performs welding according to the teaching program. In the welding experienceSierra Leone Sugar During the process, the arc sensor detects the weld seam in real time and adjusts the teaching trajectory according to the error amount to complete the welding task. At the same time, the operator can work at station 1 or station 3 Assembling curved structure workpieces.
4 Conclusion Design’s robot-based curve welding system has been used in practice, and its operating conditions are good, the welding position is accurate, and all objectives meet the design requirements: (1) ) The level of automation Sierra Leoneans Sugardaddy is high, and workers only need to load and unload workpieces, which reduces the labor intensity of workers. (2) Use robots. Welding, by replacing tooling or fixtures and calling the welding program corresponding to the workpiece, welding of curved structural parts can be achieved, which improves the production efficiency. (3) The use of contact sensors and arc sensors can accurately locate and modify the teaching trajectory in real time. , ensuring the quality of welding tools