Robotic Dishwashers And Dishwashing As A Service



There’s a story that goes back to the 1980s or so about an engineering professor who laid down a challenge to the students of his automation class: design a robot to perform the most mundane of household tasks — washing the dishes. The students divided up into groups, batted ideas around, and presented their designs. Every group came up with something impressive, all variations on a theme with cameras and sensors and articulated arms to move the plates around. The professor watched the presentations respectfully, and when they were done he got up and said, “Nice work. But didn’t any of you idiots realize you can buy a robot that does dishes for $300 from any Sears in the country?”

The story may be apocryphal, but it’s certainly plausible, and it’s definitely instructive. The cultural impression of robotics as a field has a lot of ballast on it, thanks to decades of training that leads us to believe that robots will always be at least partially anthropomorphic. At first it was science fiction giving us Robbie the Robot and C3PO; now that we’re living in the future, Boston Dynamics and the like are doing their best to give us an updated view of what robots must be.

But all this training to expect bots built in the image of humans or animals only covers a narrow range of use cases, and leaves behind the hundreds or thousands of other applications that could prove just as interesting. One use case that appears to be coming to market hearkens back to that professor’s dishwashing throwdown, and if manufacturers have their way, robotic dishwashers might well be a thing in the near future.


To be fair, the punchline to that professor’s challenge was probably somewhat undeserved. A dishwasher really doesn’t automate everything about the job of dishwashing. A grumbling teen still needs to load dishes into it, someone needs to add detergent, and the same grumbling teen has to be reminded over and over to empty the machine at the end of the cycle. So there’s still a lot of manual interaction, but it saves a great deal of work (and water) in the residential setting.

But what works in the home doesn’t work well in the food service industry. Restaurants and commercial kitchens face an entirely different scale of dishwashing problem than the residential user. Where no more than half a dozen place settings might be generated by any one meal at home, a restaurant might go through hundreds of plates, glasses, and bowls in an evening. And turnaround time is important — a residential dishwasher can sit with dirty dishes for a while, run overnight, and then be ready for the next day. A restaurant will use the same place setting for multiple seatings in a single night.

So there’s a lot of pressure on the one person in the commercial kitchen who is probably the lowest in the pecking order: the (human) dishwasher. Commercial kitchens generally have a (mechanical) dishwasher that blasts plates clean quickly with very hot, high-pressure water, but someone has to load and unload the machine, and that’s generally someone who’s about as happy to be there as the aforementioned grumbling teen. Aside from dealing with heavy piles of gross dishes and endless hours of standing while constantly being wet, dishwashers get little respect from the other members of the crew. That results in high turnover for those positions, which is a problem for management.

Robots for Very Constrainted Washing Tasks

Enter the robotic dishwasher. A startup named Dishcraft Robotics is developing a unit for commercial kitchens that aims to reduce reliance on human dishwashers. The video below shows it in action, picking up plates from a stack with an articulated arm and placing them in a free spot on a rotating triangular fixture. The fixture rotates the dirty plate to face down so that a specially designed scrub brush can press up against it, scrubbing food away while jets of water rinse it. The scrubbed plate rotates to an inspection station where machine vision checks the cleaning job, and if the plate passes muster, it slides down a ramp so it can be picked up by a gantry arm and moved to a drying rack.

Now, there are plenty of bones to pick with this setup. First of all, it’s not exactly a human-free enterprise. Someone still has to move the stacks of dishes over to the machine, and wait staff no doubt does some kind of pre-cleaning of the plates. Aside from human factors, though, the demo is highly constrained. Dishcraft states that the dishes are picked up by the arms and held in the washing fixture by magnets, meaning the plates have steel inserts in them. This of course means that restaurants have to custom source their dishware, and fine china is probably not an option. That might be fine for more casual restaurants, but it certainly won’t fly with high-end restaurateurs.

There’s also a bit of ick factor from the fact that the bottom of the plate is not scrubbed of the debris picked up from the plate below it in the stack. Dishcraft dismisses that concern by saying the plate bottoms don’t get that dirty, and a spritz of water is enough to clean it off. I wouldn’t be too sure that a health inspector would agree with that assessment, so the machine may be in for some updates before this hits the market commercially.

Dishwashing as a Service?

Obviously, a system like Dishcraft’s is going to make financial sense only to the largest of commercial kitchens. That sharply limits the potential market for these robots, so Dishcraft is considering offering dishwashing as a service. Much like restaurants get all their table linens and uniforms cleaned by services specializing in the task, Dishcraft envisions restaurants piling their soiled dishes in racks to be picked up and swapped out for clean dishes for the next day. The dirty dishes will presumably be whisked to a facility where multiple robots will scrub them clean and return them to transport containers for the trip back to the restaurant.

On the face of it, this seems like a sensible business model, and one that investors will probably appreciate as it expands the potential market to smaller restaurants. But I see a glaring problem with this model, and it echoes the apocryphal professor at the beginning of this tale: Why would you build a fleet of robots to do what a bunch of dishwashing machines that you can buy off the shelf right now can do?

As a one-off in a busy kitchen, one can make an argument for the Dishcraft robot based on labor savings and fast turnaround. But shipping the dishes off to be washed takes away the advantage of turnaround time from the end user’s perspective. It seems to me that Dishcraft is a solution in search of a problem. Yeah, it’s a pretty neat idea, and kudos to the company for at least finding a way to automate a tedious and manually intensive job. But I don’t think dishwashing as a service is destined to be the killer app they seem to think it will be.

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