Food & dining

Personal robot, I’d like some chocolate cookies, please

ario Bollini with his PR2 robot at MIT.
Mario Bollini with his PR2 robot at MIT.

If you like cookies but don’t have the time to make them, you can do a couple of things: You can use a mix, you can buy them already made, or, at some point in the future, you can get some help from a robot.

For his master’s degree in mechanical engineering at MIT, Mario Bollini taught a robot to bake cookies. He presented his project at Nerd Nite Boston at Middlesex Lounge last month. The robot, with a spatula bolted to his finger and covered head-to-toe in waterproof surgical gowns from a dentist’s office (Bollini didn’t want to damage the $400,000 PR2 robot), made several kinds of cookies. The only thing it could not do was cut the little rounds, so Bollini ended up with one giant cookie. “People get really upset if you give a robot a knife,” he explains. “It’s just a workplace safety [precaution] to not put a knife at the end of a machine that could be swinging erratically.”

The PR2 robot (PR stands for “personal robot”) was built by Willow Garage of Menlo Park, Calif., and had been part of other projects at the university. The idea to program the robot into a baker came to Bollini from Daniela Rus, MIT professor and director of the Computer Science and Artificial Intelligence Laboratory, who figured everyone likes cookies, and it wouldn’t hurt to get cookies for the lab — since the robot could make a lot of them. One cookie the robot made was chocolate Afghans, popular in Australia and New Zealand, which are a favorite of Rus because “they’re like brownies but less sweet,” she says.


Bollini, 26, who comes from Detroit, named the robot “Bakebot.” He is the cofounder of Global Research Innovation Technology, a start-up that makes off-road wheelchairs for people in developing countries.

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After Bollini programmed it, the robot used its laser eyes to determine which ingredients were in each bowl, then followed the recipe in the same order a human might. One recipe for chocolate Afghans says to mix butter and sugar first, so that’s what the robot did. Then it stirred in flour, cocoa powder, finally Rice Krispies. To help the robot distinguish ingredients of the same color, like sugar and flour, Bollini put them in different colored bowls. The most difficult part was mixing, and the robot often ended up making a huge mess. It would accidentally stick its hand into the middle of the dough and mix too aggressively or dump the contents on the floor instead of in the pan.

“It had a lot of interesting ways to fail,” says Bollini.

Bollini spent a lot of time cleaning the MIT lab floor. The robot wasted a lot of ingredients but got better over time at baking. When he was a student, Bollini worked on the project for two years.

The 25-minute recipe took the robot 2½ hours, says Bollini, because “it took him a lot of time to plan the motions to do individual actions.” On the positive side, while the robot was working, Bollini sat back and watched. In the end, the cookie tasted perfect. “Exactly how the recipe would want it to taste,” says Bollini.


No one had ever taught a robot to bake cookies before, although robots have cooked other things in other parts of the world. In Germany a few years ago, computer scientist Michael Beetz programmed a PR2 robot to make pancakes. There are robots in Japan who make sushi and ramen, robots in China who slice noodles and boil dumplings.

Bollini says it’s important to make the distinction between a robot and a machine. A machine that bakes cookies would be easier to build than a robot, Bollini says. The breadmaking machine is one example he offers. A machine doesn’t look like a person, and all it can do is the same task over and over.

A robot, on the other hand has the potential to do things that a human does, explains Stefanie Tellex, an assistant professor of computer science at Brown University, who worked on the robot project as a graduate student. “A blender has its range of uses, a dishwasher has its range of uses, but a robot has the potential to help with all of these tasks,” she says.

While working on the project, Tellex made a list of recipes that the robot could try, including cornbread, salad, and meatloaf.

The robot’s future challenges might be learning to break an egg and to cut foods, says Rus. “If we’re going to put a robot in the kitchen, the robot will have to do all the operations that are required by a recipe, and sometimes you need to cut,” she says.


But isn’t a robot wielding sha rp tools dangerous?

“We can start with plastic knives,” says Rus.

Julie Masis can be reached at

Correction: Due to a reporting error, an earlier version’s photo caption was incorrect. The image is of Mario Bollini with his PR2 robot at MIT.