Robots Can Go All The Way To Mars, But They Can't Pick Up The Groceries?

In the popular imagination, robots have been portrayed alternatively as friendly companions or existential threat. But while robots are becoming commonplace in many industries, they are neither C-3PO nor the Terminator. Cambridge researchers are studying the interaction between robots and humans – and teaching them how to do the very difficult things that we find easy.

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Stacks of vertical shelves weave around each other in what looks like an intricately choreographed – if admittedly inelegant – ballet that has been performed since 2014 in Amazon’s cavernous warehouses. The shelves, each weighing more than 1,000 kg, are carried on the backs of robots that resemble giant versions of robotic vacuum cleaners. The robots cut down on time and human error, but they still have things to learn.

Once an order is received, a robot goes to the shelf where the ordered item is stored. It picks up the shelf and takes it to an area where the item is removed and placed in a plastic bin, ready for packing and sending to the customer. It may sound counter-intuitive, but the most difficult part of this sequence is taking the item from the shelf and putting it in the plastic bin.

For Dr Fumiya Iida, this is a typical example of what he and other roboticists call a ‘last metre’ problem. “An Amazon order could be anything from a pillow, to a book, to a hat, to a bicycle,” he says. “For a human, it’s generally easy to pick up an item without dropping or crushing it – we instinctively know how much force to use. But this is really difficult for a robot.”

In the 1980s, a group of scientists gave this kind of problem another name – Moravec’s paradox – which essentially states that things that are easy for humans are difficult for robots, and vice versa. “Robots can go all the way to Mars, but they can’t pick up the groceries,” says Iida.

One of the goals of Iida’s lab in Cambridge’s Department of Engineering is to find effective solutions to various kinds of last metre problems, from putting a book in a plastic bin or harvesting vegetables, to building LEGO structures or detecting cancerous tumours. Iida’s team is also working with