Application of automatic flexible handling system

The application of robot automatic flexible handling system in the production of heavy-duty vehicles

automobile bridge box parts have the characteristics of high precision, many processing procedures, complex shape and heavy weight. In order to improve their processing accuracy and production efficiency, various heavy-duty vehicle manufacturers have adopted CNC machining centers to process such parts. When using the CNC machining center to process the workpiece, it is required that the workpiece has a very high positioning accuracy on the workbench, and the consistency of each feeding needs to be guaranteed

due to the shortcomings of manual feeding such workpieces, such as high labor intensity and poor control of feeding accuracy, they are now gradually being replaced by industrial robots or special machines

industrial robots have outstanding advantages of high precision of repeated positioning, high reliability, flexible production and high degree of automation: compared with manual work, they can greatly improve production efficiency and product quality; Compared with the special plane, it has the characteristics of flexible production and small investment scale

robot intelligent automatic handling system, as an important production link of reducer shell processing, has been successfully applied in domestic heavy-duty truck factories, but it is still not popularized. In the process of the rapid development of national economic construction, the production capacity and productivity level of heavy-duty trucks urgently need a qualitative leap, and industrial robots are the powerful propeller to improve the productivity level

layout of robot automatic flexible handling system

Figure 1 shows the site layout of robot automatic flexible handling system. The system includes 1 FANUC r-2000ib/165f robot, 1 robot gripper, 1 11m long walking axis, 2 loading and unloading slides, FANUC IR vision 2dV vision system, FANUC IR vision 3DL vision system, 5 sampling slides, and electrical control system. The system uses one robot to complete the loading and unloading of five machine tools

Figure 1 site layout of robot automatic flexible handling system

in this system, a FANUC r-2000ib/165f robot is installed on the walking shaft, which can realize the loading and unloading action of the whole system. The gripper developed based on the robot special gripper unit is very suitable for the use of poor workpiece consistency, and has high positioning accuracy and grasping stability

an industrial robot is installed on the guide rail of the walking shaft with a length of 11m. The maximum movement speed is 1.5 m/s. It is driven by FANUC servo motor. It has the characteristics of high repeated positioning accuracy, fast response speed, stable and reliable operation. In addition, the dust cover is specially designed to protect the moving parts such as guide rail, linear bearing and rack, which effectively improves the reliability and service life. In practical application, the guide rail is installed on the center line of the machine tools of the two production lines, and the motion range of the installed industrial robot completely covers the five machine tools and the loading and unloading slide area. Thus, one robot can serve five machine tools for loading and unloading

2 loading and unloading slides, each with 4 pallets, each of which can store one workpiece respectively. To realize the loading of the workpiece to be processed and the unloading of the workpiece after processing. In this system, due to the use of visual technology, the loading and unloading slide does not need the positioning device of the workpiece

fanuc IR vision 2dV vision system completes visual data acquisition by a 2D camera installed on the gripper. As a positioning method of accurately grasping the workpiece to be processed in the national billet market on the 6th, the vision system eliminates the mechanical pre positioning fixture that must be used to meet the accurate grasping of robots, and has high flexibility, making it very easy to realize the mixed production of multiple products on the machining center

FANUC IR vision 3DL vision system uses a 3D laser sensor installed on the ground to complete visual data acquisition. The vision system solves the problem of workpiece feeding position change when the positioning surface has deviation. Since the workpiece to be processed is a blank, after the robot grabs the workpiece, the position of the positioning hole for loading will change, and even the flatness of the workpiece when loading will change. This technology can automatically compensate the position change and realize high-precision feeding

5 random inspection slides are respectively for one machine tool, so as to realize the inspection of the workpiece quality processed by the machine tool at any time

the electrical control system uses human-machine interface to monitor the running state of the entire robot automatic flexible handling system. Mitsubishi q series PLC controller is adopted, and industrial fieldbus is used to realize the transmission of real-time and non real-time data in the system, which has high reliability and maintainability. The safety equipment adopts the door switch as the safety protection of the robot's working area, completely achieving man-machine isolation to ensure the safety of personnel in the automatic operation of the system

the application of this set of equipment has greatly improved the quality stability of products, saved a large number of labor, improved the automation level of enterprises, reduced the labor cost expenditure of enterprises, and improved the market competitiveness of products. The system flow is shown in Figure 2

Figure 2 flow chart of robot automatic flexible handling system

2d vision technology: automatic flexible handling of workpiece without fixture positioning

the working principle of robot automatic flexible handling system of workpiece without positioning is to use high-definition camera (vision system) to realize accurate position judgment of workpiece without positioning. After the robot receives the signal, the robot is equipped with special claws customized for the workpiece to grasp the workpiece reliably, After receiving the loading request through communication with the machine tool, the loading and unloading of the machine tool is finally completed. The system is widely used in various machining industries

the automatic flexible handling system using robots to locate workpieces without fixtures can make the production line simpler and easier to maintain, and greatly reduce the labor intensity of workers, with high efficiency and flexibility. The system is simple in structure, safe, civilized, and pollution-free. It can be applied in various machining occasions, and meets the production requirements of high efficiency and low energy consumption

fanuc IR vision 2dV vision system mainly establishes the corresponding relationship between the point position on the visual picture and the robot position through the software setting of the vision system. The workpiece is visually imaged and compared with the calibrated workpiece to obtain the deviation value, that is, the compensation value of the robot's grasp position, so as to realize the robot's automatic grasp. This means that the semiconductor module made of ultradur b4450 G5 can avoid current short circuit and destructive discharge. This technology realizes the automatic flexible handling of the robot without fixture positioning workpiece

in this loading and unloading system, the shape of the workpiece to be processed is complex, and positioning with a fixture is very complex, which is also detrimental to the expansion of similar new products in the future. After using FANUC IR vision 2dV vision system, the workpiece to be processed only needs to be placed on the pallet without positioning device on the loading and unloading slide. The actual situation is that the workpiece to be processed can move plus or minus 2 cm and rotate plus or minus 30 degrees on the pallet. This greatly reduces the design work on the loading and unloading slide and ensures the expansion function of the system

the principle of FANUC IR vision 2dV vision system is to select a workpiece to be processed as the initial workpiece, calibrate the relationship between the picture point position of the workpiece in the camera and the robot teaching point position through 2dV vision software, and complete the feature calibration of the initial workpiece at the same time. The grasping program completed by teaching is the grasping position of the initial position of the initial workpiece, and the workpiece grasping deviation value is zero at this time. When the workpiece is translated or rotated, the position changes with the position of the initial workpiece. Through 2dV software, the robot can calculate the position changes x, y, R. The robot stores the deviation value in the position register [pr]. At this time, the robot can realize the grasping of the workpiece by compensating the deviation value [pr] to the initial grasping position. The operation flow of 2dV vision system is shown in Figure 3

Figure 3 2dV vision system operation process

there is only one kind of workpiece in the application of loading and unloading. When there are many kinds of workpieces, 2dV vision system can carry out multiple feature calibration according to different workpieces to realize the switching and calling between various workpieces. It greatly improves the scalability and flexibility of the system

3d visual positioning technology helps robots load materials accurately

3d visual positioning technology is applied to robot loading to machine tools. The camera is installed and fixed on the 3DL visual support

this technology solves the problem of workpiece feeding position change with deviation of positioning surface. Because the workpiece is a blank, after the robot grabs the workpiece, the position of the positioning hole for loading will change, and even the flatness of the workpiece when loading will change. For this reason, without 3DL vision system, the robot is unable to accurately load the workpiece

its principle is: select a blank part as the initial workpiece, calibrate the relationship between the picture point position in the image head and the robot teaching point position in the MCU control system circuit as shown in the photography of the workpiece through 3DL vision software, and complete the feature calibration of the initial workpiece at the same time. The feeding procedure completed by the teaching is the feeding position of the initial position of the initial workpiece, and the workpiece feeding deviation value is zero at this time. When grasping other blank parts, the location of the positioning hole and the flatness of the workpiece change. Through 3DL software, the robot can calculate the position changes x, y, Z, W, P, R. The robot stores the deviation value in the position register [pr]. At this time, the robot can realize workpiece loading by compensating the deviation value [pr] to the initial feeding position

2dv is to calculate the plane change through the camera, and 3DL is to calculate the spatial change through the camera and laser. In fact, 3DL is a comprehensive application of 2dV and laser technology, which greatly increases the feasibility of system design, especially in the case of workpiece design with deviation of positioning surface

soft float function: compensate the position deviation of the robot gripper when grasping the workpiece

soft float function is applied to the workpiece grasping and the loading and unloading steps of the robot machine tool

in this project, the robot gripper is located on the workpiece to be processed, and the position of each workpiece is different from the position of the positioning hole, and the foaming ratio is 10-30 times different. The change of the position of the blank surface and the locating hole will cause a series of problems, including: when the workpiece is in the pallet and the robot grabs it, the deviation caused by the blank surface will cause the workpiece to move when grabbing with the gripper, and friction will occur with the pallet when the deviation is large; When the robot cuts materials from the machine tool, due to the deviation brought by the blank surface, the hand grip cannot fully fit the blank surface. Even if it fits hard, there will be serious friction when the workpiece is separated from the positioning pin, resulting in a collision alarm

although there is 2dV visual compensation, the blank surface cannot be used as a feature quantity, resulting in the constant change of the position of the workpiece grasped by the robot claw, and the robot cannot compensate for this deviation

when the soft floating function is enabled, the robot can change its posture by external force, and the size can be changed through parameter setting. The gripper can change its posture according to the blank surface when grasping the blank, so as to achieve a complete fit and avoid collision and friction

in this project, the fitting accuracy between the workpiece positioning hole and the machine tool positioning pin (conical) reaches 0.01 mm. The repetition accuracy of the robot itself is greater than 0.01 mm, resulting in the workpiece feeding position deviation. At this time, by applying the soft floating function, the robot first grabs the workpiece and runs to the taper part of the positioning pin, which is clamped by the machine fixture. The robot moves to the upper feeding position through the soft floating, so as to realize feeding