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  What Is A Robot?

First, let’s get an overview of what a robot is and what parts it consist of. When you have an overview of the different parts of a robot, you will be able to understand what you are going to do later on in this course and why you are doing it.

Robots come in many different shapes and forms. You have the humanoid type of robot, the one that looks like a human with legs, arms and head. You have flying robots, underwater robots and wheeled robots that drives on land.

By Forschungslabor Neurorobotik der Beuth Hochschule für Technik Berlin (link)

How to build a robot

No matter which type of robot it is, a robot needs the following:

  • Motors for moving
  • Sensors for seeing
  • Electronics for making decisions

And of course, it needs a structure to hold it all together.

Motors for moving

Many different motor types exist in the robotics world – and they don’t all work the same way.

The most standard motor is the DC motor. It has two wires. You connect them to a battery, and the motor shaft starts spinning. Very straight-forward. The DC motors is the most common type of motor to use for moving a robot with wheels. If you want to spin it the other way around, you switch the plus and minus (although some DC motors have internal controllers that only allow it to turn one way).

The stepper motor is a motor where you can control the rotation of the motor shaft in steps. You can for example use it to turn the shaft exactly half of a spin. Or five spins. These are often used for example in 3D printers, where you want to control the movement of the printer head very precisely.

A servo motor has a shaft that doesn’t normally turn continuously. It has a “home position” and you can control the shaft to turn a number of degrees to either side from this position. It is very commonly used for example in a robotic arm.

You can also find something called a brushless DC-motor. The brushless DC-motor is a more efficient and quiet DC motor. But it needs some extra controller electronics to work. You can recognize a brushless DC motor by it’s three connection wires instead of just two.

Sensors for seeing

To be able to interact with the outside world, a robot needs sensors. Sensors are devices that can sense things, for example sound and light. We humans have eyes to see things and ears to hear things. These are our “sensors”.

A robot uses cameras, microphones, bumper sensors and more to sense the world around it.

Electronics for making decisions

A robot needs some electronics to make decisions based on what it sees through its sensors. For example for a light-following robot, the electronics would need to receive light information from a sensor, then decide which motors to turn on to move closer to the light.