# The World of Robotics ## Where does the word "robot" come from? Did you know that the word "robot" was first used in a play in the 1920s? That is right! The word "robot" was introduced by the work of the Czech writer Karel Capek, entitled R. U. R. (Rossumovi Univerzalni Roboti), which means Universal Robots of Rossum, in English, written in 1920. The word comes from the Czech word Roboti, meaning "hard work". In the play, the robots are machines that look like humans, and invented by them.
## After all, what is a robot? A robot is a mechanism that is basically formed by joints and links. The joints have motors and they are programmable so they can move within its environment to perform the desired tasks.

Representation of a robot with links and joints. It has motors on its joints, so it can move the links.

### Exercise 1. How many joints does the following robot have?
{% hint style="info" %} **Answer** Two {% endhint %} ## What types of robots are there? ### Manipulators Manipulators, as the name suggests, are robots able to manipulate objects; they can move an object in the environment to another position. The most common examples are industrial robots, and they look like arms, as the examples below. We can also attach a tool to the robotic arm to help with the manipulation. This tool will act like our hand, but not necessarily need to have the format of a hand, or have fingers.
### Bi-manual manipulators Manipulator robots can have one arm or more. The ones that have two arms are called bi-manual manipulators. In this case, the world "bi" refers to "two".
### Mobile robots The mobile robots are able to move, some have wheels and some have legs. In the examples below, on the left we have a robot with legs that moves like an insect. On the right, we have a robot with wheels, similar to the vacuum cleaner robots that you might have seen.

Robot with legs

Robot with wheels

### Mobile manipulators The mobile manipulators have the characteristics of a manipulator robot as well as the characteristics of a mobile robot. A robot with wheels **and** an arm, for instance, is a mobile manipulator.
### UAVs UAVs is an acronym for “unmanned aerial vehicles”, meaning they are robots that can fly with no pilot on board. Have you ever seen people taking photos or filming with drones? Drones are examples of an UAV.
### Humanoids Humanoid robots are robots that look like a human. In general, we call humanoids the robots with two legs, two arms, a torso and a head. How cool are they?
### Exercise 1. What type of robot is the one below?
2. What type of robot is the one below?
{% hint style="info" %} **Answers** 1. Mobile robot 2. Manipulator {% endhint %} ## What is a rigid body? You can squish a sponge and change its shape, but you cannot do this with a chair made of wood, right? In this case, the chair is considered a 'rigid body', and the sponge is a 'deformable' object.
Photo of a chair by Kelly Miller on unsplash
Photo of sponge by Artem Makarov on Unsplash
### So what? Why are rigid bodies relevant to robotics? If you pick up a chair by its back and move it, the whole chair moves, not only its back. Why is that? This happens because the chair is a rigid body. Since rigid bodies are not 'deformable', when you move a part of this object, the whole object (body) moves in the same way. A robot with a rigid body is easier to program because we know the overall shape won't change, whereas if it was squidgy, it is much harder to program how to move it. ### Exercise Can you tell what object is a rigid body from the list below? 1. A bottle made of glass. 2. A pen. 3. A bag of chips. 4. A table. 5. A marble (toy). 6. Play dough. {% hint style="info" %} **Tip** If you can apply a force, for instance, squish the object, and it does not change its form, it is a rigid body. {% endhint %} {% hint style="info" %} **Answers** 1. A bottle made of glass - rigid body. 2. A pen - rigid body. 3. A bag of chips - deformable body. 4. A table - rigid body. 5. A marble (toy) - rigid body. 6. Play dough. - deformable body. {% endhint %} ## References: * (2004) Human-Robot Interaction. In W. S. Bainbridge (Ed.), Berkshire Encyclopedia of Human-computer Interaction. Berkshire Publishing Group. * ISO 8373:2012 (en) Robots and robotic devices - Vocabulary. Available from . Accessed on 8th September 2020. * descomplicandoarobotica. Available from . Accessed on 15 August 2023. * The robot images are from the CoppeliaSim simulator. Available from . Accessed on 21 August 2023.