机械专业毕业设计（论文）外文翻译-基于PLC的加工中心刀库换刀控制系统设计.doc

陕西理工学院毕业设计论文Based on the PLC machining center tool change control system designRan Longjun ( Shaanxi Institute of Mechanical Engineering College of mechanical engineering and automation professional machine from class 082, Shaanxi Hanzhoung 723003)Teacher: Hou HonglingIn the machining of the workpiece, the tool magazine of the CNC machining center to be based on processing requirements tool automatic tool changer, tool changer CNC machine tools in general has two control methods, that is, fixed access to the tool changer control and random access tool changer control.Fixed access to the tool changer control, the location of each tool in the tool magazine is fixed.Tool (CNC to the T code) instruction is based on the pocket number of the access address to control the knife kept the knife action.Ie, where the original knives, knife set number after use, still the return of that knife sets.In the control of the random tool change, but also the location of the knife is the random tool selection (CNC T-code) instruction has nothing to do with the pocket number is random changes in instruction only tool direct number.This tool change the way in the new knife after removing the tool magazine without rotation, immediately randomly deposit originally used tool, tool changer, kept the knife at once, reducing tool change time.T-function based on the pocket coding processing diagram.T code of numerical control system sends instructions to the FLC PLC after decoding to retrieve the data in the table, find the address of the T code is specified in a new sword, where the data table, and compared with the current knife, if inconsistent, then the tool magazine rotation controlThe signal sent to the control system of the tool magazine, until the positioning number location to a new knife, tool magazine to stop the rotation, and is ready to tool change.The CNC machining center small tool library adopts PLC control, the control program using a structured design ideas, the control program is divided into: record of the current tool, request tool, dial rotation direction judgment and transfer tool change time to time and tool change indicatorflashing and other parts, respectively, to compile the various part of the program, and finally integration of the master control program, the control program of structural good, readable, programming and operating efficiency.PLC control system by small tool library for the CNC machining center, stable performance, affordable, good results.PLC control of the CNC machining center tool library automatically select the application design, suitable for the transformation of the economic type CNC machining center and CNC machining centers.The design of CNC machining centers, tool change time can be shortened to optimize the processing performance of CNC machining centers, to improve the efficiency and economic benefits of CNC machining centers. PLCs -Past, Present and FutureEveryone knows theres only one constant in the technology world, and thats change. This is especially evident in the evolution of Programmable Logic Controllers (PLC) and their varied applications. From their introduction more than 30 years ago, PLCs have become the cornerstone of hundreds of thousands of control systems in a wide range of industries. At heart, the PLC is an industrialized computer programmed with highly specialized languages, and it continues to benefit from technological advances in the computer and information technology worlds. The most prominent of which is miniaturization and communications.The Shrinking PLCWhen the PLC was first introduced, its size was a major improvement - relative to the hundreds of hard-wired relays and timers it replaced. A typical unit housing a CPU and I/O was roughly the size of a 19 television set. Through the 1980s and early 1990s, modular PLCs continued to shrink in footprint while increasing in capabilities and performance (see Diagram 1 for typical modular PLC configuration). In recent years, smaller PLCs have been introduced in the nano and micro classes that offer features previously found only in larger PLCs. This has made specifying a larger PLC just for additional features or performance, and not increased I/O count, unnecessary, as even those in the nano class are capable of Ethernet communication, motion control, on-board PID with autotune, remote connectivity and more. PLCs are also now well-equipped to replace stand-alone process controllers in many applications, due to their ability to perform functions of motion control, data acquisition, RTU (remote telemetry unit) and even some integrated HMI (human machine interface) functions. Previously, these functions often required their own purpose-built controllers and software, plus a separate PLC for the discrete control and interlocking. The Great CommunicatorPossibly the most significant change in recent years lies in the communications arena. In the 1970s Modicon introduction of Modbus communications protocol allowed PLCs to communicate over standard cabling. This translates to an ability to place PLCs in closer proximity to real world devices and communicate back to other system controls in a main panel. In the past 30 years we have seen literally hundreds of proprietary and standard protocols developed, each with their own unique advantages.Todays PLCs have to be data compilers and information gateways. They have to interface with bar code scanners and printers, as well as temperature and analog sensors. They need multiple protocol support to be able to connect with other devices in the process. And furthermore, they need all these capabilities while remaining cost-effective and simple to program. Another primary development that has literally revolutionized the way PLCs are programmed, communicate with each other and interface with PCs for HMI, SCADA or DCS applications, came from the computing world. Use of Ethernet communications on the plant floor has doubled in the past five years. While serial communications remain popular and reliable, Ethernet is fast becoming the communications media of choice with advantages that simply cant be ignored, such as: * Network speed. * Ease of use when it comes to the setup and wiring. * Availability of off-the-shelf networking components. * Built-in communications setups. Integrated Motion ControlAnother responsibility the PLC has been tasked with is motion control. From simple open-loop to multi-axis applications, the trend has been to integrate this feature into PLC hardware and software. There are many applications that require accurate control at a fast pace, but not exact precision at blazing speeds. These are applications where the stand-alone PLC works well. Many nano and micro PLCs are available with high-speed counting capabilities and high-frequency pulse outputs built into the controller, making them a viable solution for open-loop control. The one caveat is that the controller does not know the position of the output device during the control sequence. On the other hand, its main advantage is cost. Even simple motion control had previously required an expensive option module, and at times was restricted to more sophisticated control platforms in order to meet system requirements. More sophisticated motion applications require higher-precision positioning hardware and software, and many PLCs offer high-speed option modules that interface with servo drives. Most drives today can accept traditional commands from host (PLC or PC) controls, or provide their own internal motion control. The trend here is to integrate the motion control configuration into the logic controller programming software package. Programming LanguagesA facet of the PLC that reflects both the past and the future is programming language. The IEC 61131-3 standard deals with programming languages and defines two graphical and two textual PLC programming language standards: * Ladder logic (graphical). * Function block diagram (graphical). * Structured text (textual).Instruction list (textual). This standard also defines graphical and textual sequential function chart elements to organize programs for sequential and parallel control processing. Based on the standard, many manufacturers offer at least two of these languages as options for programming their PLCs. Ironically, approximately 96 percent of PLC users recently still use ladder diagrams to construct their PLC code. It seems that ladder logic continues to be a top choice given its performed so well for so long. Hardware PlatformsThe modern PLC has incorporated many types of Commercial off the Shelf (COTS) technology in its CPU. This latest technology gives the PLC a faster, more powerful processor with more memory at less cost. These advances have also allowed the PLC to expand its portfolio and take on new tasks like communications, data manipulation and high-speed motion without giving up the rugged and reliable performance expected from industrial control equipment. New technology has also created a category of controllers called Programmable Automation Controllers, or PACs. PACs differ from traditional PLCs in that they typically utilize open, modular architectures for both hardware and software, using de facto standards for network interfaces, languages and protocols. They could be viewed as a PC in an industrial PLC-like package. The FutureA 2005 PLC Product Focus Study from Reed Research Group pointed out factors increasingly important to users, machine builders and those making the purchasing decisions. The top picks for features of importance were. * The ability to network, and do so easily. Ethernet communications is leading the charge in this realm. Not only are new protocols surfacing, but many of the industry de facto standard serial protocols that have been used for many years are being ported to Ethernet platforms. These include Modbus (ModbusTCP), DeviceNet (Ethernet/IP) and Profibus (Profinet). Ethernet communication modules for PLCs are readily available with high-speed performance and flexible protocols. Also, many PLC CPUs are now available with Ethernet ports on board, saving I/O slot space. PLCs will continue to develop more sophisticated connectivity to report information to other PLCs, system control systems, data acquisition (SCADA) systems and enterprise resource planning (ERP) systems. Additionally, wireless communications will continue to gain popularity. * The ability to network PLC I/O connections with a PC. The same trends that have benefited PLC networking have migrated to the I/O level. Many PLC manufacturers are supporting the most accepted fieldbus networks, allowing PLC I/O to be distributed over large physical distances, or located where it was previously considered nearly impossible. This has opened the door for personal computers to interface with standard PLC I/O subsystems by using interface cards, typically supplied by the PLC manufacturer or a third party developer. Now these challenging locations can be monitored with today a PC. Where industrial-grade control engines are not required, the user can take advantage of more advanced software packages and hardware flexibility at a lower cost. * The ability to use universal programming software for multiple targets/platforms. In the past it was expected that an intelligent controller would be complex to program. That is no longer the case. Users are no longer just trained programmers, such as design engineers or systems integrators, but end-users who expect easier-to-use software in more familiar formats. The Windows-based look and feel that users are familiar with on their personal computers have become the most accepted graphical user interface. What began as simple relay logic emulation for programming PLCs has evolved into languages that use higher level function blocks that are much more intuitive to configure. PLC manufacturers are also beginning to integrate the programming of diverse functions that allow you to learn only one package in configuring logic, HMI, motion control and other specialized capabilities. Possibly the ultimate wish of the end-user would be for a software package that could seamlessly program many manufacturers PLCs and sub-systems. After all, Microsoft Windows operating system and applications work similarly whether installed on a Dell, HP or IBM computer, which makes it easier for the user. Overall, PLC users are satisfied with the products currently available, while keeping their eye on new trends and implementing them where the benefits are obvious. Typically, new installations take advantage of advancing technologies, helping them become more accepted in the industrial world. The cases of CNC machine tools has input, output device, programmable controller, servo system, testing and feedback device and host machine. The input device may be of different processing information to the meter computer. CNC machine tools in the initial stage, the input device is a punched tape, is now gradually eliminated; at present, the use of the keyboard, disk, greatly facilitate the information input job. Output output internal operating parameters (including machine normal, ideal working condition of the original parameter, fault diagnosis parameters ), general in the machine just work state to output of these parameters with record keeping, after working for a period of time, then the output with the original data for comparison, contrast, can help to judge the working maintenance of machine tool normal. Numerical control device only the core of CNC machine tools and dominant, the completion of all processed data processing, calculation, finally realize the NC machine tool function command. It contains the circuit of the computer, all kinds of excuses circuit, CRT display hardware and corresponding software. The programmable controller to realize the control of spindle unit, the program speed commands are processed by the controlling spindle speed; management tool library, automatic tool exchange, tool selection, tool, cutter accumulative used times of residual life and props grinding times management; control main shaft reversing and stop, stop, cutting fluid switch, chuck clamping and loosening, mechanical hand for knives and other movements; also on the machine ( external switch trip switch, a pressure switch, temperature control switch, control ); the output signal (tool, mechanical hand, rotary table, etc.) to control. Detection and feedback device composed of a detecting element and a corresponding circuit, mainly is the detection of the velocity and displacement, and the information feedback and control the device, to achieve closed-loop control in order to ensure the machining accuracy of NC machine tools. NC machining process for complex, more content, including parts of structure, process analysis, process design, processing procedures for the preparation, selection of tools and methods of use. Adjustment of machine tool mainly comprises a tool named, transferred to the knife, the workpiece is mounted, cutter, measuring tool, machine tool components state wait for multinomial job content. Program debugging is on the program itself logic problems and reasonable design of checking and adjusting. Test cut success before the parts are formal processing, and the processed parts detection. The first three steps are the standby time, improves the work efficiency, hope the standby time as short as possible, the more conducive to the rational use of machine tool. The index has direct effect on the machine utilization assessment ( machine real rates ) machining center automatic tool changing system of the tool change is divided into two steps: first CNC system receives TXX automatic tool selection, and then execute the M06 code, the mechanical hand finishing tool automatic exchange. General by the mechanical hand implement tool automatic switching method of controlling the movement of the same basic tool selection mode, but will have a direct impact on the entire tool changing system efficiency. This paper discussed in NC system how to use its special function and PLC indirect addressing instruction automatic control knife library arbitrary choice knife.TRIZ is the former Soviet Union, led by G.S.Altshuler scientists in the technical system evolution based on the rule, build inventions and technological innovation of new theory approach. Technical system evolution in the 8mode, the 39general engineering parameters,40 inventive principles, conflict resolution,39x 39matrix of 76 standard solutions, the solution of inventive problems algorithm ( ARIZ ) and engineering knowledge effect library composed of TRIz theory and method system.TRIZ thinks, product evolution is the process of products to solve the existing conflict process, promote its to the idealized direction. Technical conflict is a typical engineering problem of compromise, i.e. when improving system a technical characteristics ( parameters ), another character ( parameters ) may worsen. TRIZ innovation theory is the core of technical system in the presence of conflict, conflict matrix is to solve the technical conflict effectively tool. Once the technical problems as technical form of conflict, to the question of the technology in the field of specific terminology to describe the conflict, and the conflict is converted to TRIZ general engineering parameters, finally by the general engineering parameters in the technical conflict resolution matrix selection can be used of inventive principlesThe machining center use large amounts of memory type optionally, the way to tool and cutter library head location ( address ) via code recognition system corresponding to the memory system in NC tool PLC, regardless of where the knife shell will alway