Californias motion-control gold mine

DN Staff

August 26, 1996

15 Min Read
Californias motion-control gold mine

It may be the weather that attracts people to California, but it's the business climate that keeps them there. Home to 31-million people, California boasts an annual gross state product of $533-billion. By either measure it's larger than Canada. And, were it a country, the economic output from this land of gold, silver screens, and silicon chips would be the ninth largest in the world.

Within this thriving framework--forming what might be called an "economy of motion"--are dozens of motor and controller companies. Many of them lie, strangely enough, alongside some of California's largest earthquake fault lines, dotting the state from San Diego to San Francisco. And they produce everything from sub-fractional-horsepower motors to turnkey machine control systems.

To uncover some of these companies' latest innovations, Design News journeyed to five firms and interviewed their top engineers. We quizzed them about recent developments occurring in the motion-control industry, and challenged them to dazzle us with a selection of their most recent products. What did we find? A range of trends, including:

? Motion control is riding the same processing-power wave that fuels the computer industry.

? As the capabilities of the hardware soar, users have found it almost impossible to write the massive amounts of required software themselves. Thus, several companies have focused their efforts on developing tools to ease the programming burden.

? New, easy to setup motion-control cards will begin to take advantage of the plug-n-play features incorporated into operating systems like Microsoft's Windows 95.

? Ultra-high speed milling machines, being put into service by companies like Detroit's Big Three automakers, require ever more sophisticated motion-control systems to take advantage of the new-found speed.

So sit back and enjoy the view as the Design News technology tour travels the state from south to north to take in California's best motion-control scenery.

Oriental motor steps in

Just outside the City of Angels, in Torrance, lie several of the largest Japanese motor manufacturers in the United States. Two of these "motor" companies, Honda and Toyota, produce engines of the internal-combustion type. The third, Oriental Motor, has spent the last eighteen years in the US supplying high-torque, low-noise step motors and drives. What the company hasn't made is controllers. Until now.

The SC8800 and SC8800E are a pair of easy to use step-motor controllers. They program via a standard RS-232 connection to a computer or ASCII terminal, and are identical, except for the model E's inclusion of an encoder input.

Most uniquely, the controllers are the first Oriental Motor products engineered and manufactured entirely in the United States. "There is the possibility they might even be exported to Japan," says Philip Santarelli, manager of marketing and sales promotions.

With "simplicity" as their guiding principle, engineers imbued the SC8800 with onboard software saved in 64k of non-volatile memory. This design eliminates setup diskettes and the need to learn a proprietary input program. An intuitive language consisting of extremely abbreviated commands--some just a single letter--appeals to the low-volume customer that might not be familiar with elaborate motion-control systems. "We found that people were using programmers to set up this kind of product," says Nick Johantgen, engineering manager. "We don't have programmers to work with; some of our customers are machinists with a high school diploma."

Development spanned several years, and the SC8800 is actually the second iteration of the product. The first, never really offered for sale, boasted eight optically isolated programmable outputs, eight programmable inputs, dedicated limit switch, step and direction signal, fail-safe magnetic brakes, and onboard power for all those devices. "It was very expensive," Johantgen says. "We tried to do too much."

The experience, however, allowed him to create the SC8800 in just four months. He also leveraged the knowledge of Seiberco, Braintree, MA, a motion-control company that is now a subsidiary of Oriental Motor and is manufacturing the controller.

Specifications for the new controller include four programmable inputs and two programmable outputs, all optically isolated. The SC8800 is eight times as fast as the first-generation device with a maximum velocity of 800,000 steps/sec. It also offers linear S-curve and parabolic acceleration/deceleration profiles.

Johantgen emphasizes that the SC8800 will be a powerful tool to help the company sell its strength--motors and drives. Users who prefer to buy from a single source now can. "If you need a motor and drive, you also need a controller," says Johantgen. "So why let customers walk somewhere else?"

Staking out the high end

Up the road in Northridge--more earthquake country--the 120+ employees of Delta Tau Data Systems quietly turn out what they claim are some of the most sophisticated motion-control cards in the world. The company specializes in difficult applications, especially those requiring several coordinated axes. Its core product, the PMAC or Programmable Multi-Axis Controller, can command up to eight axes of motion simultaneously. And while other companies produce products that can equal the PMAC's raw speed and resolution, Delta Tau has striven to stay one step ahead with the "little details" that make the difference between success and failure for some applications.

Curtis Wilson, the company's vice president of engineering and research, notes that Delta Tau was the first to use digital signal processors (DSP) and the first to use sixteen-bit digital-to-analog converters (DAC) in their controllers. "My old professors would cringe, but there is virtue to throwing speed and resolution at a problem," he says.

The PMAC's specs read like a power-junkie's wish list. Each contains a Motorola 56000-series DSP interfacing with up to four 10,000-gate arrays, allowing internal calculations to be performed down to the microsecond. A single gate-array provides four channels of I/O, allowing sixteen axes of I/O and eight axes of motion overall.

With a 30-MHz clock (20 MHz available), the PMAC covers a velocity range from 0.0001 to 15 million counts/sec and a position range of plus or minus 32-billion counts with an accuracy of plus or minus 1 count. Trajectories and moves are based on algorithms and include advanced contouring methods, such as splines and PVT (position-velocity-time). "We solve continuous equations rather than simple if-then statements," says Dimitri S. Dimitri, Delta Tau's president.

Why go to this much trouble? "Our goal is to never have the PMAC be the limiting factor in a design," says Wilson. "The user will run into physical limits with the machine before the PMAC restricts him."

The company recently introduced the PMAC2, a fully digital controller that can directly generate the six signals needed to power a three-phase motor. "Power transistors for motor drives are driven digitally using pulse-width modulation," says Wilson. "Using a normal controller you have to convert the signals from digital to analog and back to digital." The PMAC2 eliminates this conversion process. And for those applications that exploit the technology, the controller provides 15-20% higher performance than the straight PMAC at a lower system cost.

Such power and flexibility point to the PMAC's biggest disadvantage: user friendliness. "We're known as very powerful, but tough to use," sighs Dimitri. "If you want to go from A to B, we give you a dozen ways to do it." To address this issue, engineers are developing an "expert system" software program that will walk users through the setup process.

But this hasn't stopped Delta Tau from looking for even more power. Wilson described innovative look-ahead algorithms--available in 1997--that will allow the controller to anticipate moves well in advance and slow the machine tool before sharp changes in contour. Now, without the look-ahead, it's possible to have a tool move so fast that the machine's momentum cannot be stopped in time to change direction. "It's like driving without headlights," explains Dimitri.

Wilson and Dimitri can rattle off lists of applications that blossomed using PMAC. A radio telescope, for instance, formerly required three weeks and $30,000 for tuning the motion system. "They put in the PMAC and tuned it in ten minutes," says Wilson. "System payback time? Twenty minutes."

Custom controller

Jacob Tal, president of Galil Motion Control, takes great pride in what he believes are his company's strengths: price/performance, custom designs, and ease of use. Two new products reflect that philosophy, he says. The DMC-1410, a 11/2-axis controller, pushes into the large market of simple applications. And at the high end, the DMC-1700 may well be the market's first plug-n-play controller.

Galil's twenty-five employees work from a new 24,000 sq-ft building in Mountain View. The facility is 2.4 times as large as the previous space, indicative of the company's 35% annual revenue growth rate.

Unlike Delta Tau--which sells one version of each of its controller products--Galil specializes in producing custom designs to satisfy specific customer needs. "One-third to one-half of our OEM users have some kind of variance in the firmware," says Tal. To date, the company has created more than 500 of these "specials". Wayne Baron, vice president of engineering, explains that many of these custom designs can be created in a matter of hours by leveraging the huge library of specials done in the past.

Though the DMC-1410 controls just 11/2 axes, it offers nearly the same features as Galil's 8-axis DMC-1000. Compact, it fits in a half-size ISA slot. A 32-bit microprocessor and 16-bit DAC combine with an 8-million counts/sec encoder feedback and a positioning range of plus or minus 2-billion counts. A 250-line memory (half that of the DMC-1000) frees the host PC. Inputs from two encoders allow the 1410 to perform electronic gearing or CAM applications, as well as the usual jogging, point-to-point positioning, and contouring operations.

The 1410's real strength, however, is in performance for the price. Initially, it will cost about half as much as the DMC-1010 multi-axis controller did when introduced. "We are making our sophisticated technology available to users who only need a single axis," says Tal.

At the other end of the scale, the DMC-1700 leverages the popularity of Microsoft's Windows operating system to bring ease of use to the power user. Enhanced onboard communications get away from the traditional first-in-first-out (FIFO) messaging scheme. FIFO can tie up the communications channel, and it proves weak in applications where the user needs constantly updated positions. To get around this, engineers added a second channel dedicated to providing status information to the host program. For PCs with no available DMA channels, it can also be configured as FIFO with about a 25% performance loss.

Other nice touches include a new 100-pin, high-density connector and EEPROM flash-memory firmware updates. "Now users won't have to wait for a new EPROM from us," says Baron, "They can have different firmware for different applications."

Though based on the DMC-1000, the 1700 is 1.5-times as fast, with sample times as low as 83musec/axis. It boasts improved EMI shielding to help customers more easily obtain certification for their machines. And, of course, it's plug-n-play, automatically setting itself up and loading the necessary drivers when used with Windows 95 or NT. Says Baron: "Being easy to use has always been one of our big selling points."

Controlling the software crisis

Just north of Oakland, in Richmond, and not too far from the San Andreas fault, engineers at Berkeley Process Control (BPC) see a possible disaster coming. However, you won't find this temblor in the local terra firma--it's rocking the machine-control industry.

Just what is this looming crisis?

Software: thousands upon thousands of lines of machine-control program code, bursting forth from the engineering departments at most of BPC's customers at an ever increasing rate. "Software is emerging as the most critical issue in machine control," says Paul Sagues, BPC's president. "It's doubling every two years. We see it as the number one problem."

Not just empty rhetoric, BPC supports this view with figures drawn from industry and its own experience. In a paper titled Crisis in Modern Machine Control, Sagues and BPC co-founder David Auslander--a professor at the University of California Berkeley--note that in 1981 the company's average project required 8K bytes of software. Today, it's 8M bytes. Over at the semiconductor consortium Sematech, engineers attribute more than 50% of wafer-fab failures to the control program.

Faced with this software explosion, developers have a choice: hire lots more programmers, reduce the product specs, or have the machine-control company provide more software. BPC, of course, suggests the last option in the form of a direct multi-tasking machine control system called MachineWorksTM.

MachineWorks consists of an integrated combination of the company's Bam controllers, a color touch-screen operator interface, and the necessary multi-axis amplifiers, servos, and Micro I/O racks. Recent additions include a programmable limit switch and the integration of up to 56 axes. Based on a 64-bit RISC processor, MachineWorks provides a simple method for developing control programs for everything from flying shears to machine tools.

Uniquely, users need no experience with either conventional programming or motion control. Instead of spending days, weeks, or months crunching thousands of lines of code, developers program MachineWorks by entering the complete machine sequence with touch-screen menus written in familiar terminology, without a keypad, prompt, or syntax. All diagnostics and error handling--an especially difficult programming task--are included.

Though very simple to program, MachineWorks is actually tailored towards multi-tasking, asynchronous applications. Complex machine operations are programmed as individual tasks and then executed simultaneously. "The more complex, the greater advantage we have," says Steve Kraft, product development manager. "It is absolutely the fastest way to commission a machine that needs multi-axis, multi-tasking control."

Why? First, it provides an organizational structure for building a machine-control program. Also, it includes several man-years of programming that the customer doesn't have to develop from scratch. BPC's engineers write it once, and everyone can use it via MachineWorks, says Kraft. "If I'm going to put a complex phone system into my company, I wouldn't go out and buy some phones and write my own voice-mail system," he explains, "but people try that with machine control all the time."

Programming made simple

Learning a foreign language--with the unfamiliar vocabulary and sentence construction--is always time consuming, often frustrating. Motion-control programming languages are no exception. To be proficient, users must remember volumes of arbitrary and sometimes arcane syntax and commands. And while the power programmer might be able to recall hundreds of commands and parameters, the casual user is stuck leafing through manuals.

At Compumotor, Rohnert Park, engineers developed a solution for this problem. Called Motion BuilderTM, it's an iconic programming system for Compumotor's 6000 series of controllers that runs under Microsoft Windows 3.1 or 95.

Motion Builder shortens the learning cycle for control-system development by allowing users to design and program in a familiar way--using flowcharts. They can simply drag and drop icons, representing motion functions, on the program workspace. Application parameters are entered into dialog boxes that pop up when the user double-clicks on one of the icons. The equivalent of more than 250 programming commands are accessible right from the icon palette, and another 100 can be found in other areas of Motion Builder.

Users define program flow by linking the discrete icons together with lines. This method allows for easy experimentation, since individual icons or even blocks of icons may be left in the workspace and quickly added or removed from the program by drawing or deleting links. When complete, each program may be compiled and executed.

Custom commands may be added to extend the capabilities of the system. "We hope to eventually make a library of user-written routines available for download off our BBS," says Cook. Eventually, Motion Builder's ability to shield the user from the actual command syntax could let Compumotor engineers completely change the underlying control language, and yet present the user with a constant programming interface.

Motion Builder's primary advantage is speed. "An expert user can probably write a program in one-third the time with this," says Bob Cook, controls engineering manager. "A novice would save even more time than that." Though Cook acknowledges that Motion Builder itself has a learning curve, he stresses that it is much less than that of the control language.

Other advantages include:

? Reduced mistakes. "Motion Builder generates error-free code--something even the expert can benefit from," says John Walewander, product planning manager.

? Quicker troubleshooting. A debug mode lets users step through the code line-by-line to spot logic errors.

? Easier sharing of work. Programs might be as large as 150K--enough to fill 80 printed pages. Following the flow and logic of another engineer's program visually with Motion Builder is much easier than doing it manually.

Compumotor sees benefits for its support staff as well. The company's technical applications department receives 3,000 calls a month, and an ever-increasing number of the questions involve programming. The hope is that the simplicity of Motion Builder might break the trend.

The system traces its roots to a request from Parker Hannifin's Hydraulic Valve Division (HVD). Engineers there wanted Compumotor to create a visual programming interface for their hydraulic controls. But as the project progressed, it became apparent the power of such a tool was applicable for a broader range of products, and Motion Builder was born. Says Cook, "HVD alone probably got a ten-fold increase in functionality from this."

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