be a “huge facilitator in taking bin-picking technology from emerging to mature.”

Trick bag

To some degree, successful bin-picking “comes down to how many tricks you have in the bag,” Shafi says. Depending on part geometries and application requirements, Shafi has developed bin-picking systems that rely on either fixed mount overhead cameras, arm-mounted cameras and hybrid combinations of both, as well as those that use laser-based structured lighting or laser dots.

Other techniques include switched lighting, in which lighting sources are fired as needed based on where a part to be picked is located within a bin—say, in a corner or near a sidewall. Yet another technique involves taking two or three images of a part very rapidly, each with different lighting, as an aid to finding its 3D position. This can be particularly helpful when parts are partially occluded, Shafi says.

If an application allows it, Shafi observes, a fixed-mount overhead camera solution is usually most desirable. After a part has been picked, the vision system can be working on the next part to be picked while the robot arm is placing the part. Secondly, a moving arm-mounted camera risks collisions with bin walls or parts, for example, which is not a concern with a fixed-mount camera, Shafi points out.

One company that has done extensive experimentation with bin-picking is American Axle & Manufacturing Inc., a Detroit-based maker of driveline and chassis systems. Over the past 18 months, the company has worked with Shafi on several potential bin-picking applications—both random and semi-random—involving parts such as forged axle shafts, cast differential carrier housings and forged pinions, says Dan Bickersteth, American Axle corporate manager for cycle time improvement and automation.

Already viable

So far, the company has chosen not to purchase and install any of the bin-picking projects developed, but not because they didn’t work, Bickersteth says. “I’m becoming more and more confident that bin-picking is going to be viable, and in certain applications, it’s already viable,” he declares.

Some bin-picking applications could produce a simple return-on-investment for American Axle within about two years, Bickersteth estimates. But for now, he indicates, that’s not quite good enough—given other automation opportunities that have a 12- to 18-month payback potential.

“Right now, we’re pursuing a set of projects that don’t involve vision. They’re much more straightforward automation, so we’re kind of focused on those,” Bickersteth explains. “But I think that these bin-picking applications will come to be,” he adds. “It’s just that they’re probably a year, or maybe a year-and-a-half down my list.”

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at www.automationworld.com.

See sidebar to this article: Single-Camera Bin-Picking