The natural thinking, when you automate something, is to take a robot and try to have it mimick the tasks a person does when they do the process. The challenge is, a person has a pretty complex controls system. A robot doesn’t.
- As a person moves to pickup a part, they adjust the speed and position of their hands using their eyesight based on where the part is and where their hands are (think of catching a baseball). This is light-years beyond what a robot can do.
- A person has thousands of nerve-endings (sensors) and two hands that serve as phenomonal grippers.
- A person uses force-feedback to ‘feel’ what they are doing. A person can sense where an object’s centre of mass is and if they’ve grabbed it correctly.
- Finally, a person has intuition. A person unconsciously processes all this data and gets a gut feel that something is wrong when something doesn’t feel, look, or sound right.
All these abilities, that a person inherently has, make it easy for a person and very challenging for automation to handle complex processes (think of parts that are floppy (i.e. plastic bags, or bags of chips), or parts that are complex shapes and can get tangled together/interlocked, or food products that are soft or jelly-like, etc.)
With robotics, the secret is: Don’t try to do it all at once like a person does. Break it down.
Take bin-picking as an example. A lot of people try to solve it straight-up, the same way a person does. Sometimes you can, with basic parts. But sometimes you can’t because of the complexity of the parts.
A person looks at the bin and, in a split second, decides which part makes most sense to pickup. An automation system can solve the same problem by breaking the process down into a series of manageable steps.
Step #1: Get part out of bin – Keep it simple, use brute-force when you can!
- Dump the bin of parts?
- If they’re metal, use a magnet to grab a bunch at a time?
- Use a bowlfeeder to feed them?
Step #2: Get part singulated – How can I get them separated so I can grab just one?
- Drop them onto a table where they’ll sit flat?
- Set them on a vibratory table where you can get some separation?
- Use a series of belts of increasing speed to create gaps between parts?
Step #3: Get part located – Accurately locate the one I want
- Use hard tooling to get individual parts into a known location?
- Use simple vision to locate the part in 2D space and pick it up?
You’ve now solved the application with simple technology. Don’t get me wrong, there’s a place for 3D vision-guided robots and force-feedback systems and sometimes they make the most sense. BUT, sometimes a series of brute force, simple steps is a beautiful thing!