This robot is a ‘Cheetah’

Robots are developing at an incredible rate, with their ability to perform real-world tasks improving almost by the minute. Such rapid development doesn’t come without downsides, and there are many people who believe that artificial intelligence (AI) could become too powerful, leading to the possibility of robots taking our jobs, or perhaps even taking over the world! Whilst these fears might not be completely unjustified, let’s instead focus on the positives for the time being and marvel at the astonishing accomplishments being made in the field of robotics.

The Cheetah robot, developed by scientists at MIT, is roughly the same shape and size as a small dog, and has been designed to be able to walk across difficult terrains efficiently and effectively. Such a trait is particularly useful when we need to explore dangerous and hazardous environments that may be unsuitable for humans, such as the Fukushima nuclear power plant that collapsed in Japan in 2011. Like all robots, it uses algorithms to help it to navigate, stabilise itself, and ensure that its movements are natural. The latest version, the Cheetah 3, was unveiled in early July, and I think it’s fair to say that it wouldn’t look too far out of place in the animal kingdom!

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[Image courtesy of Sangbae Kim, MIT]

Perhaps the most impressive feature of the Cheetah 3 is that the strangely adorable hunk of metal performs the majority of its navigation without any visual input, meaning that it is effectively blind. The researchers at MIT believe that this is a more robust way to design the robot, since visual data can be noisy and unreliable, whereas an input such as touch is always available. Let’s imagine that you are in a pitch-black room; how would you find your way around? Your eyes are pretty much useless, but you can use your sense of touch to feel around the environment, making sure that you don’t bump into walls or obstacles. It’s also important to step carefully, so that you don’t misjudge where the floor is, or tread too strongly and break through something. The Cheetah 3 takes all of this into account as it gracefully glides across even the roughest terrain.

One of the key ideas that was addressed in the new model is contact detection. This means that the robot is able to work out when to commit to putting pressure on a step, or whether it should swing its leg instead, based on the surface that it is stepping onto. This has a massive impact on its ability to balance when it is walking on rough terrain, or one that is full of different obstacles; it also makes each step quicker and more natural. Going back to our dark room, you are likely to step quite tentatively if you can’t see where you are going as this will allow you to react to whatever surface you come into contact with, and adjust your motion as required. With the latest update, the clever ‘canine’ can make these adjustments by itself in a natural manner.

The Cheetah 3 also contains a new and improved prediction model. This can calculate how much pressure will need to be applied to each leg when it experiences a force, by estimating what will happen in half a second’s time. Returning once again to our pitch-black room, imagine how great it would be if you were able to predict what you’re about to step on and adjust your path accordingly – no more treading on sharp objects or stubbing your toe! The scientists tested the power of the new model by kicking the robot when it was walking on a treadmill. Using its prediction algorithm, the Cheetah 3 was able to quickly calculate the forces it needed to exert in order to correctly balance itself again and keep moving. Whilst I can confirm that no animals were harmed in the making of this robot, whether or not the robot itself felt harm is perhaps a question for another day…

The new and improved Cheetah 3 is certainly one of the more remarkable recent accomplishments in the field of robotics. Its natural movements and quick corrections mean that it excellently mimics animal navigation, and it is easy to see how such a robot would be extremely useful for exploring dangerous terrains. Such incredible progress in the study of robotics is as impressive and exciting as it is scary. While it is extraordinary that we are able to replicate animal movements so closely, it has rightly made many people slightly worried; will robots eventually be able to completely replace us? We can only cross our fingers that these critters have no plans for world domination just yet…

Kai Laddiman

Play Nice!

Whoever said having fun is more important than winning was not a game theorist. Game theorists are mathematicians who study games, and how to win them. But they aren’t just interested in Snakes and Ladders – game theory also involves studying ‘games’ like nuclear standoffs, trade wars and even the competition of species as they evolve.

New research from the Institute of Science and Technology in Austria (http://dx.doi.org/10.1038/s41586-018-0277-x) might help us to use game theory for environmental good. Their findings look at perhaps the single most important problem we face in looking after the environment – ‘the tragedy of the commons’.

The tragedy of the commons plays out all around us, and relates to situations where everybody stands to benefit from damaging a useful shared resource. Everybody in the office exploits the ‘commons’ of the biscuit tin by taking a biscuit, but nobody can be bothered to go out and buy a new packet to keep the tin full. Eventually, the tin is empty, and everyone has to endure life without biscuits whilst someone looks for more. Such pointless suffering could have been avoided if only someone had acted sooner!

In a more serious setting, the tragedy of the commons can lead to catastrophic results. Take deforestation – the shrinking of the world’s forests as we use trees faster than they can grow back. It is in the individual interests of each logging company to spend all their time chopping down trees (which makes them money) and to waste none of it replanting them (which doesn’t). At least, in the short term. But over time, this clearly won’t work – the ‘commons’ of the world’s forests will be so damaged that everyone will lose out. Bad news for all you atmosphere fans out there.

The new research uses game theory to study the tragedy of the commons, to try and understand what we can do to prevent it. To stick with the logging example, the researchers treat logging companies as players competing in a series of very simple games, over and over, learning each other’s tactics. Each game is just a matter of choosing one of two options: Chop down trees without bothering to replant them, or take the time to replant them as well. Each time the choice is made, the company gets a reward depending on what they picked; they will get a bigger reward if they don’t use any of their time replanting. It looks like companies that are perfectly happy to drop-kick Dr Seuss’ orange defender-of-the-trees, the Lorax, are going to do better than their greener rivals.

At least, initially. The key to the new research is that in it, the games that have already been played affect the rewards up for grabs in the next game. If you keep choosing not to replant trees, then you may do better than your opponents in each game, but you’ll gradually make the rewards smaller and smaller as you start to run out of trees to cut down. So, you can’t just think about the profits to be won in today’s game – you have to think about what you’ll be playing for in tomorrow’s game too.

The researchers found that this makes a big difference to how companies will play. If previous games made no difference to the current game, then companies which don’t replant trees would do better than their replanting rivals. But, given that failing to replant the trees you cut down means worse prizes in the future, the companies which do replant end up doing a lot better than those that don’t bother. In other words, it pays to play nice.

The one catch to this is that the prizes have to get significantly worse when you choose not to replant. So, in practical terms, these findings suggest ways to make the ‘game’ of logging less environmentally devastating – by changing the rules. For instance, governments could pass laws which force any companies failing to replant trees to pay an increased tax on any future trees they cut down (or maybe pay for the Lorax’s extensive pension plan). This makes logging more like the game the researchers studied, where past choices quickly and significantly affect future rewards. So based on the researchers’ findings, such a law would make sure that doing the right thing and replanting trees is the better choice.

Yes, game theory is about winning. But by figuring out which rules reward the sort of people who go out and buy more biscuits for the tin, we can make sure the ‘winning tactic’ for the world’s most dangerous games is to play nice.

Joe Double

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