I, foodbot: declining costs, faster speeds and advances in vision-guided systems are helping food and dairy plants justify the cost of robotics

Dairy Foods, Jan, 2005 by Kevin T. Higgins

More often than not, collaboration depends on an integrator, and it is the integrator's decision on whose robot to use with which vision system. BluePrint Robotic Solutions in Boulder, Colo., recently designated Cognex Corp.'s In-Sight vision sensor as its system of choice for high-speed robotics. BluePrint also is an integrator for ABB, which no longer develops robotic solutions for non-automotive applications. BluePrint works primarily with Delta-style robots, the metallic spider arms used frequently for pick-and-place. ABB and SIG/Doboy are the primary suppliers of Delta parallel-axis robots.

ABB's Delta robots can pick up to 150 pieces per minute, and picking them off a moving conveyor and in a random orientation requires a vision system that not only processes images quickly but also judges distances. Cognex made the transition in 1997 from pixel-by-pixel comparison to geometric pattern matching, or 3-D imaging. According to BluePrint's Joe Crompton, director of software and controls, "even their base model can keep a robot supplied with well over 200 targets per minute.

"Food and beverage is one of the biggest segments in robotics vision," he adds, "and the potential is huge."

Faster processing speeds have resulted in a single camera serving four or more robots in some applications. Two years ago, a dedicated camera for each robot was the rule of thumb. Inconsistent lighting and surface finishes on packages still pose challenges, Crompton says, but today's systems are expanding their role in quality-assurance, particularly in the handling of raw foods such as frozen entrees. His firm recently designed a vision-guided, tray-loading robot that works in a freezer.

While working at TechniStar, Crompton helped integrate vision-guided robots on Pepperidge Farm's Milano cookie line in the late 1980s. Inspection functions were "rudimentary" at that time. "Now we're getting into recognizing shapes, whether product is broken or the right color, and it's done with vision systems that cost less," he says.

Adept Technology Inc. provided the vision-guided robots in the earliest Milano applications. "Compared to then, vision systems are probably five to ten times faster now, costs are down substantially and cycle rates are going up," reports John Dulchinos, general manager of the Livermore, Calif., firm's robotics division. With 3-D vision, overlapping cookies on a moving belt no longer pose a problem, he says. Speeds have more than doubled to 100 to 130 parts per minute.

Adept's SCARA (selective compliance assembly robot arm) robots are an alternative to Delta-style robots for high-speed picking. Though lacking the range and degrees of freedom, SCARA units boast compactness, fast acceleration and high-repetition accuracy. Precision is important in electronics and automotive assembly, though delicate food products like a 5 gram cookie are better served by a soft touch. When capping the two halves of cookies, the SCARA units sometimes are programmed to sandwich them slightly off center. "to make it look home-made," says Dulchinos. About 1,000 Adept robots are in service in food plants worldwide, he estimates, with frozen food, candy and bakery applications most prevalent. Handling baked goods as they exit an oven is a task especially well suited to a robot. Otis Spunkmeyer, for example, slashed product damage rates dramatically with a vision-equipped muffin tray-loading system.