Robots Add Safety and Flexibility for Manufacturers

Great strides are occurring in machine vision, benefiting conventional sortation systems and the rapidly emerging collaborative robotics sector.

By Kevin T. Higgins, Managing Editor

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Technology is getting closer to replicating human sight, although it still has a ways to go. Similarly, multi-axis machine motion offers new options in manufacturing, though it’s still no match for hyper-flexible people.

On the other hand, vision systems never blink, and robots seldom take a day off. Robots, vision systems and robots with vision may never duplicate multifunctional workers, but the trade-offs are shrinking and counterbalanced by other capabilities.

Replacing human eyes to perform high-speed product inspections was the logical starting point for vision technology. These applications arguably are the most industrially hardened and are where the latest advancements are first implemented. An example is a new digital sorting platform from Key Technology Inc., Walla Walla, Wash. After two years of development and beta-site shakedowns, Key recently presided over the commercial introduction of Veryx, described as a “multi-sensor pixel fusion” platform that can be incorporated in both chute and belt sorters.

Greater versatility, higher throughput and fewer rejections of good product are the key deliverables to manufacturers, but what’s under the hood also is notable. Signals from up to four camera and eight laser-scanner channels are joined simultaneously for sub-millimeter pixel level accept/reject analysis. The prior art required layering feedback from cameras and scanners, resulting in false rejects of good product suspected of being bad. Synchronized LED lighting and a powerful processor support the high-resolution digital cameras and lasers with up to four wavelengths.

Food companies that process potatoes, dried fruit, nuts and other products may not know or care about Key’s vision advancements, which Steve Johnson, senior director-sales and marketing, calls “one of the most significant the company has made in sorting technology.”

Depending on the application, they may opt for fewer cameras and lasers or even stick with older vision systems on existing belt and chute sorters — though that would deprive them of what Johnson refers to as “cool time processing” advances. These include simplified controls, self diagnostics and a degree of artificial intelligence that allows the system to react to color changes that occur because of raw-material variability.

Four cameras are enough to provide a 360-degree view of a nut or other product as it drops down a chute. Like Key’s Tegra machine, one camera is capturing an image from a bottom view. Unlike Tegra, the sensor has a vertical window positioned at a low angle, where dirt and moisture is less likely to build up and obscure the view. “The machine was designed around the location of the bottom sensor,” Johnson asserts.

Vision is an option or a standard offering on a growing number of robots. Auburn Hills, Mich.-based ABB Robotics began integrating vision-guided technology in some machines two years ago, using array-style cameras from Cognex in new ones and as a retrofit in late-model robots. Motion is slower than with a point-to-point machine, allows Rick Tallian, manager-packaging products and applications, but functionality is expanded.

Integrated vision is useful in automated palletizing to verify the correct shipping label is affixed and is in the correct orientation. It’s even more useful for depalletizing. “A pallet stack is never perfect,” he says, “so when you pick off of a pallet, the machine needs help identifying where the material really is.” Less mechanical fixturing is required, helping to shrink the cost differential.

“There is a tremendous amount of work going on with 3D cameras,” Tallian adds. “I’ve been involved in vision guidance since the early 1990s, and it’s a really exciting time.” Plummeting camera costs, the ability to extract and analyze huge amounts of controls data and technical advances like structured-light 3D scanners are pushing vision well beyond simple shape recognition. “It’s going to change a lot of things,” he believes.

A wink and a nod

ABB’s April acquisition of Gomtec GmbH is expected to rejuvenate its efforts in the area of human-robot collaborative automation technologies, with a new generation of “safe by design” machines expected to debut early next year. ABB will be playing catch-up with firms like Rethink Robotics Inc. in Boston. Still a modest $100 million segment of the global robotics market, collaborative robot sales are expected to grow 50 percent this year.

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