Today we are talking about emotions and robots with Daniel Henneken, a CNRS researcher from the University of Lille.
Today you will tell us about how robots feel.
Yes, and since we humans are so much inspired by the creation of robots, we can first ask ourselves a question about our own feelings. And it’s easy there!
Yes, we have 5 senses, sight, hearing, smell, taste, touch.
Yes, these are the 5 historical senses, but we must at least add a sense of balance that allows us, among other things, to stand up, which is nothing. And then there is everything that is called proprioception, how we feel our body, hunger, thirst, the state of muscles, joints, etc. All these signals are obviously very useful, and if they are for us, then for the robot. However, with nuances: for example, it is not very useful to give a sense of taste to a robot that cannot eat!
Effective! And suddenly how to give these sensations to the robot?
It’s a bit the same principle as for living beings, you have to equip them with sensors. For example, the sensation of temperature that we feel when we touch an object is provided by thermoreceptors located on the skin. These are neurons that convert temperature fluctuations into a nerve impulse that is transmitted to the brain. Well, in order for the robot to have the same sensations, we will provide it with temperature sensors that will convert the temperature measurement into an electrical signal, which will then be processed by the robot’s processor.
What are these temperature sensors?
Well, we will use the property of some materials to have an electrical resistance that depends on temperature. Electrical resistance is a property that characterizes the ease with which an electric current can pass through a material. If it changes due to temperature, as with rust, the current changes and therefore the temperature can be determined directly.
Did you say rusty? Are temperature sensors made of rust?
Yes, with iron oxide, but it can also be other materials, such as chromium oxide or manganese oxide. So, if we continue with touch, another important sensation is the sensation of grasping, which means that when you pick up an egg, you don’t crush it. Finally okay!
Ah, it’s a story of pressure, isn’t it?
Exactly. And therefore it is important that the robot feels the pressure that it exerts on the object. To do this, you can use another physical property of some materials – the piezoelectric effect. When you press these materials, they generate an electrical current, and so, again, the electrical current received by the robot’s processor allows you to know the pressure being applied to the sensor.
Piezoelectric effect, that means something to me. Is it not used in gas lighters?
Yes, small gas lighters without batteries that spark when you push the handle, it’s exactly the same principle, except you have to press hard enough to create a spark of almost 1000 volts.
What materials have this property?
Oh, there are many. The most commonly used are PZT, lead titanozirconates, hence oxides containing titanium, zirconium and lead. Of course, there are dozens of other sensors, and if you’re interested, I’ll be at the booth at the Science in Books Festival in Villeneuve-d’Ascq on Thursday and Friday to present some of them. Admission is free and I will post the details on ramenetascience.fr as usual.