Computer numerical control systems (Computer Numerical Control, CNC) is controlled by computer processing, digital control system, which consists of hardware and software components, with the versatility, high reliability, feature-rich, mechatronics, etc., to achieve control, interpolation, feed and other basic functions and compensation, image editing and display options. Currently has interoperability, portability, etc. secondary development of open CNC system is an advanced manufacturing technology is an important research fields.
计算机数控系统(Computer Numerical Control,CNC)是用计算机控制加工过程,实现数字控制的系统,其由硬件和软件组成,具有通用性强、可靠性高、功能丰富、机电一体化等特点,能实现控制、插补、进给等基本功能及补偿、图形编辑和显示等选择功能。目前具有可互操作性、可移植性、可二次开发性等优点的开放式数控系统是先进制造技术的重要研究领域。
1. The role of electric bending machine
1.电动折弯机的作用分析
Bending sheet metal manufacturing and processing machine plays a very important role. Bending machine is used to manufacture large size, shape accuracy are higher, relatively large bending radius of curvature becomes profiles, sheet metal bending molding has developed into an important industry technology carrier. Therefore, the bending machine control system research is constantly evolving. Currently in the domestic hydraulic type CNC bending machine occupy absolute advantage, but it and all hydraulic systems, are easy to pollute the environment, the hydraulic cylinder slow response, low productivity, the structure is more complex, higher maintenance costs and other shortcomings, and Since the last century since the eighties no significant technical improvements. Based on direct drive servo motor CNC bending machine technology is an emerging technology. There is a PC-based open CNC bending machine is designed based on the location of the control card CPLD to implement digital - Pulse servo interface and other I / O interface feature, but the material is bent by the hydraulic system to achieve complete.
折弯机在钣金制造加工中起着十分重要的作用。折弯机是用于制造尺寸大、外形准确度要求较高,相对弯曲半径大的变曲率型材,已发展成为板料折弯成型行业的重要技术载体。因此,对折弯机控制系统的研究也在不断发展中。目前在国内液压型折弯机数控系统占据着绝对的优势,但其和所有的液压系统一样,具有易污染环境、液压缸响应慢、生产效率低、结构较为复杂、维修成本较高等缺点,且自上世纪八十年代以来再无重大技术改进。基于伺服电机直接驱动的折弯机数控技术则是一门新兴的技术。还有一种基于PC机的开放式折弯机数控系统,设计了基于CPLD的位置控制卡来实现数字-脉冲伺服接口和其他I/O接口功能,但对材料的折弯实现是由液压系统来完成。
This paper presents a PC-based open-electric bending machine CNC system, which uses servo motor direct drive slider, the slider control on both ends of the parallel structure of synchronous mode, meanwhile, it uses a PC-based motion control interfaces boards, servo system hardware architecture and real-time Linux operating systems, professional CNC software EMC2 software architecture. Experiments show that the system is low cost and high reliability; bend in the material on, X-axis and Y-axis positioning accuracy can be well positioned to meet the practical requirements of industry.
本文提出一种基于PC机的开放式电动折弯机数控系统,它采用伺服电机直接驱动滑块,在滑块两端的同步控制上采用并行结构方式,同时,它采用基于PC机、运动控制接口板卡、伺服系统的硬件结构和实时Linux操作系统、专业数控软件EMC2的软件结构。实验证明,该系统具有成本低、可靠性高等优点;在对材料的折弯上,X轴和Y轴的定位精度都能很好地满足工业实际要求。
2. Electric bending machine CNC system design
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The system hardware consists of a PC, motion control interface board, servo drives, servo motors and feedback devices composed of five parts. PC, the whole system management functions, the choice of operating system software as a platform for RTLinux by EMC2 CNC software for system man-machine interface and task allocation, real-time display position of each axis data and various status information, and through this interface to Motion control board to send control commands to drive the servo system to achieve control in sheet metal bending.
Motion control interface board master chip FPGA (Field Programmable Gate Array, a field programmable gate array), the board via the PCI bus is connected with the PC, the PC hair down while receiving a command, the other real-time feedback to the PC position of each axis data and system status information. Fed back to the grating with a given axis position information to compare the location information, to achieve closed-loop control system, the position, and then through the servo interface to constantly adjust the displacement of each axis, so as to ensure the implementation of control precision bending. Servo drives and servo motors to achieve the X-axis backgauge plate, Y-axis slider drive, servo motor encoder comes with closed-loop control of the motor speed; grating as a feedback device, the y-axis slider position data in real time feedback with motion control interface board for processing, constitute the slider position closed-loop control system. 3. Profile bending machine works
Bending machine main achieve free movement in both directions, respectively, the horizontal movement of backgauge (i.e., controlled by the servo motor in this article the X-axis) and the vertical movement of the slider (i.e., controlled by the servo motor in this article Y- axis movement). The use of a common mold, by controlling the X-axis and Y-axis position, can be folded into a variety of shapes of parts. Specific implementation process: after the first move to a blocking plate to determine the location of the workpiece bend limiting side bending and bending position, the slider according to the desired bending angle down to a certain depth under the bending mold, and then return Repeat the process until the finished workpiece bending.
CNC bending machine advantage is largely determined by its control accuracy, mainly reflected in the slider on both ends of the synchronization issues. Based on the servo motor direct drive electric bending machine synchronization control on both ends of the slider, the general structure and the use of master-slave parallel structure in two ways. As way of parallel structures are not prone to accumulate positioning errors, but also less prone to resonance phenomena, makes the system has strong anti-interference ability. Since the system is designed to bend power system, a long slide beam, in order to effectively prevent the slide beam in a downward bowing when bending force and to improve the parallelism of the slider, so that better control precision bending, using the three support columns and three servo motors driven by slide bending, were placed in the left slider (Y1-axis), the end (Y2-axis) and right (Y3 axis), wherein, Y1 and Y2 axes mainly from mutual, Y2 and Y3 axis also from each other mainly. Three servo motors to obtain the same location at the same instruction coordinated synchronized movement, so as not to slide down tilt caused by bending accuracy even mechanical damage. This is different from the general CNC bending machine CNC differences and difficulties. To ensure the position error at any time axis are controlled in a predetermined range, in order to achieve synchronized movement of the slider.
4. Conclusion
Electric bending machine bending machine is the development trend, and open CNC system is the main direction of the development of numerical control system, to combine the two, can not only overcome the traditional shortcomings inherent hydraulic bending machine, and can reduce the system well costs, the system has a higher cost. This design of open-high-power electric bending machine CNC system, using PC, interface board and servo motion control system structure, the Y-axis parallel structure way, using == servo motor to drive the slider joint The campaign to make the system more stable, more accurate control, but also openness, hardware and software-rich, portability, ease of human-computer interaction. Experiments, the system in the X-axis and Y-axis positioning accuracy are good to meet the actual requirements of the industry. On the other hand, the system needs to be further improved GUI, a GUI with more simple and beautiful; adopt more cost-effective equipment to improve the system of feedback data processing power, you can further reduce system cost and improve the control precision bending, which is expected in the next study phase implementation.