IT'S A SIGN of the times in the CNC machine marketplace for machine builders and end users to see their influence contracting, and be forced to downsize their companies or go out of business entirely. So, as the demands for machine performance, reliability, and after-sales support grind onward, the companies that prosper will be those that keep their automation and controls at the forefront of machine performance. To succeed at this means having an unswerving commitment to look for and use promising software architectures.
Our company, ANCA Pty. Ltd., is a private, Australian manufacturer of CNC machines providing equipment to global, first-tier companies such as Rolls Royce, General Electric, Samsung, Boeing, Daimler-Chrysler, Caterpillar, and Volvo. ANCAs computer-controlled grinding machines and software are found in power-train applications in the automotive industry, medical devices, specialized tool grinding, gear grinding, aerospace, and other industries. These ever-increasing customer demands require ANCAs machines, software, automation, and processes to continue changing at a rapid pace.
We need to support and offer the latest technologies to our customers, says Gerard Cullen, ANCAs CNC architect. In an industry where performance, time and available money are crucial, ANCA actively investigates any new technology that may provide a better experience for our customers.
Our CNC machine and its performance have evolved through an interesting sequence of operating system improvements, starting with rolling our own Assembly language code to XP Embedded with a concurrent, real-time operating system during the past five or so years.
In the Beginning
In the early 1980s, ANCA expanded by applying its high-level engineering and mathematical skills to produce complete machine tools. The company developed sophisticated CNC tool-grinding machines that combined new technology with operating simplicity.
The first ANCA systems were built on one CPU running our own embedded code, written in Assembler, along with a basic user interface that showed machine position, and not much more, says Cullen.
In the early '90s, needing a much better operator interface, among other things, the company moved to a hardware platform built on QNX. This was an x86 RTOS that included, for its time, a well-developed graphical user interface, says Dave Fisher, ANCAs OEM business development manager. No other OS was used on the machine because we wrote our own windows for QNX, so QNX was doing the RTOS and GUI for the machine. We did this on our own motherboard with an Intel CPU. We started with QNX2 and moved to QNX4.
Moving to Windows
In the late '90s, ANCA changed its operating system to Windows, because the QNX OS platform lacked processor support, and wasnt keeping up with Microsofts Windows user interface. However, the company knew Windows alone was unable to meet the control demands of its CNC equipment. We needed the 3-D data presentation and user interface available on Windows, but had to maintain the software precision required for numerical control.
Wed already decided on Windows, and we needed to find a product to allow us to maintain our single CPU architecture, says Cullen. There were two products that would allow this: INtime real-time OS that runs in parallel with Windows from TenAsys and RTX real-time extension from VenturCom (now Ardence). INtime appeared to be the more advanced both in development and features.
Fisher remembers that both products were young in terms of clear applicability. At the time, the two products on the market were very immature, recalls Fisher. INtime looked to be slightly more advanced than the other.
At about the same time, Windows CE was making news, but ANCAs team was certain that Windows CE wasnt a suitable option. We were very happy with the real-time performance of QNX, and a RTOS is required for our application, says Fisher. The version of QNX had become outdated, and the GUI had fallen behind. We had the option to update to a newer version on QNX, or make the change to Windows with a real-time extension.
However, making its decision didnt mean its transition was easy. The RTOS and Windows NT proved to be a big challenge in the early '90s, adds Fisher. Both products werent entirely stable.
Transition to a New OS
Rewriting the operator interface of ANCAs CNC system for Windows was a given, since ANCA was interested in using UI features of Windows that simply werent available from QNX. However, transferring the heart of the real-time CNC code from QNX to the INtime RTOS was a more delicate issue, given the time and effort that went into designing and validating the real-time control elements. An unreliable CNC with an advanced 3-D interface, no matter how visually appealing, would never sell, says Fisher.
Consequently, the team ported from QNX to INtime using an internally developed compatibility fix, referred to as shim technology, to maximize preservation of existing control code. That code was up and running relatively quickly, and continues to work today, he adds.
ANCA shipped its first product based on INtime in 2000. The INtime API and RTOS have remained stable since the initial shipment of our Windows-based product, says Cullen. This allows us to concentrate on increasing the performance and complexity of our control algorithms without worrying about the stability of the underlying RTOS. This was vital since ISA support disappeared from our platforms several years ago. Translating real-time ISA hardware support code to PCI was far easier under INtime than it ever would have been under QNX. The INtime RTOS hasnt caused any bottlenecks for ANCA, and has never prompted us to review our decision to choose INtime.
The stability of the product is important. Development of the INtime RTOS provided additional functionality that ANCA needed, and because of a stable API, upgrading from one version of INtime to another was a painless and trivial exercise. A fully featured RTOS with Windows allowed us to continue developing ANCAs control product, including the latest Windows versions and service packs, development environment integration, and PCI device support.
Deterministic Behavior Must Be In Time
Upgrading from Windows NT to Windows XP was about a six-month exercise, recalls Cullen. Most of this work was updating Windows GUI applications and learning about Windows XP Embedded. It was clear we still needed a real-time operating system.
Windows XP is capable of providing fast overall response times, but it is not appropriate, on its own, for our applications, which require hard real-time determinism. For example, a Windows application thread, regardless of its priority, is susceptible to preemption by many software and hardware sourcesincluding interrupts and high-priority kernel and driver threads.
Windows XP Embedded is a tool for developing a managed OS feature set. However, for all its advantages, XPe doesnt address determinism. While processes available for Windows to run can be limited by XPe, the systems overall determinism cant be managed.
We needed an RTOS to satisfy the remaining requirements of accurate and repeatable data acquisition. We chose INtime for just this purpose.
The INtime real-time OS doesnt require special hardware. It operates in a separate virtual machine on the same PC platform thats running Windows XP, says Fisher. Its use didnt result in any increased hardware complexity. Software development also is unchanged because it uses the same Microsoft Visual Studio development environment used to build standard Windows XP and XPe applications.
Application software running on the real-time OS always performs data acquisition and control at the highest priority, with overall system supervisory tasks and data display on the user interface, running at lower priority.
The Windows Advantage
The ANCA operator interface revolves around highly mathematical concepts, using 3-D data presentation. Our 3-D simulator (See Figure 1 below) runs on a standard Windows platform, allowing easy transfer between the ANCA CNC equipment and the R&D lab, explains Fisher.
FIGURE 1: SIMULATION SAVES
With simulation, customers can eliminate usng expensive blanks. Running the simulator directly on the CNC equipment saves thousands of dollars in destroyed tool parts by avoiding expensive tool crashes during trial runs. ANCAs previous CNC solution required a separate QNX desktop box for test, development, and simulation. Windows eliminated that need.
Consequently, one simulator that can run on both the desktop and the CNC equipment is a significant cost and time saver for our customers. A task that might take 10 minutes to grind can be simulated in five to 10 sec. With simulation, customers can save hundreds of dollars by eliminating use of expensive blanks. Running the simulator directly on the CNC equipment likewise saves thousands of dollars in destroyed tool parts by avoiding expensive tool crashes during trial runs.
The previous CNC solution required a separate QNX desktop box for test, development, and simulation. Windows eliminated the need to purchase and maintain a specialized and expensive desktop box. Our customers simply use their existing Windows workstations.
From this operating system migration path came our flagship product, TX7+, a five-axis tool and cutter grinding machine with a 37 kW grinding spindle able to run at 10,000 rpm. It has grinding speeds to 6,000 mm/min and rapid speeds of 15,000 mm/min. Programming resolution is 1 µm (0.001mm) for linear axis and 0.001 deg for rotary axis (See Figure 2 below).
|FIGURE 2: A NEW GENERATION|
From its operating system migration, ANCA built its flagship, TX7+, a five-axis tool and cutter grinding machine with a 37 kW grinding spindle able to run at 10,000 rpm. Programming resolution is 1 µm for linear axis and 0.001 deg for rotary axis.
ANCAs latest CNC and Digital Servo Drive system is the 5DX generation. The single-processor architecture provides high processing speed and improved reliability. Data doesnt need to be transferred from the user interface processor to the machine control processor. One processor handles all functions without compromising speed and performance.
The touchscreen interface is a more natural interface for the operator, eliminating the need for an external pointing device.
USB support lets the user connect, as needed, USB flash disks, external hard disks, printers, digital cameras, etc. The CD read/write DVD read function enables easy backup and permanent storage. It also facilitates future software upgrades quite easily. A built-in modem allows remote monitoring, diagnostics and support. We also include network backup including intranet access and file transfer to workstations (See Figure 3 below).
|FIGURE 3: VERSATILE INTERFACE|
USB support lets the user connect, as needed, USB flash disks, external hard disks, printers, digital cameras, etc. The CD read/write DVD read function enables easy backup and future software upgrades. Inbuilt modem allows remote monitoring, diagnostics and support.
Its is very important to ANCA that its machines be internationally capable. Because the operator interface runs on Windows, ANCA equipment supports as many as 15 different languages, including Chinese and several other Asian languages.
Having a worldwide customer base means remote access to the CNC equipment is a necessity for diagnostics and software updates. Every control system we ship includes a modem and software configuration ready for remote diagnostics, says Cullen. This includes file transfers using standard Windows networking and remote desktop control via NetMeeting. The flexibility of the Windows networking product means all we need to do is create the modem or Internet connection, and Windows will do the rest. Typically, this is used as a service tool to retrieve files, install software updates, and view machine status as the operator sees it. However, this link is also available to the customer to monitor machine operation. In addition, ANCA provides tools to help operators monitor machine operation, whether theyre on site, up in the office, or out on the boat or golf course. One customer uses a webcam to monitor and remotely control his CNC machine over the Internet from his home.
Dual-Core Coming Next
We will keep riding the PC hardware technology wave, says Cullen. Dual-core processor technology is a good example of this. When we need to embrace it, the technology will allow us to further optimize the performance and responsiveness of our motion control and machine safety software, while having minimal impact on our CAD/CAM application software. INtime 3.0 can make the transition to this technology an almost transparent upgrade. All we need to do is configure INtime to run our real-time software on one processor, and leave the other for Windows to manage. From ANCAs perspective nothing changesthe real-time OS just takes care of it. Were excited about the possibilities that this technology will give us.
ANCAs use of qualified, off-the-shelf motherboards keeps its CNC platform on par with advances in computer technology, and translates to faster cycle times for the real-time control element with more complex computations for more accuracy at the tool.
The system inevitably will have to get faster, but thats not an immediate concern, says Cullen Weve run our system at 1 ms, but this kind of speed is generally not needed for most of our applications. Because ANCA has high-speed digital signal processors (DSPs) in the servo drives, the company doesnt have to update the CNC as often as other designs.
Speed always is application dependent, adds Fisher. With the introduction of components such as linear motors, we might be looking at much faster speeds in the future.
Control System Evolution,
Intelligent Machine Design
OVER THE years, ANCA moved through a progression of operating system improvements dictated by a desire to use emerging technology to satisfy customer demands for better performance. Heres a capsule summary:
- 1974: Hardwired NC
- 1977: ANCA System 200Computer Automation naked mini-computer
- 1982: ANCA System 2000Intel 8088 using Intel MultiBus
- 1991: ANCA System32Intel 486 DX66 using QNX2
- 1998: ANCA 3DX Control SystemIntel Pentium Pro using QNX 4
- 2000: Windows NT (SP3) product (INtime V1.2 RTOS) release, Pentium 2 266 MHz
- 2001: Upgrade to Windows NT SP6 with INtime V2.1 RTOS, Pentium 3 600 MHz
- 2003: Upgrade to Windows XP Embedded, Pentium 4 2.4 GHz, platform, PCI SERCOS master card
- 2004: ANCA 5DX Control SystemIntel Pentium 4 2.8GHz, USB I/O and touchscreens
- 2005: Windows XP SP2, re-entry to the OEM control market
- Future: Multi-core processor technologies, Windows Vista, INtime V3.0 RTOS, next evolution of control system
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