Introduction
One spy, of course, has his own super-car. In order to use the car to the best of its abilities, one must be aware of some physics concepts. In this lesson, we will build a robot that practically demonstrates what is inertia.
Construction
As you can see in the picture below, the brick of the robot is attached to a peculiar position. The reason for this is to move the center of mass of the robot forward. You will learn how does that help us understand inertia after you build the robot.
Inertia Bot - LEGO Mindstorms Robot with a large inertia cargo
There is a lot of physics and math involved when learning with LEGO Mindstorms EV3 robots. It is generally "difficult" to include them directly during classes because students are coming for "something funnier" and at the same time, they could be of different ages. But Inertia is a pretty common topic that is quite easy to introduce to students, especially with a robot.
The robot moves and stops. What will happen with the cargo when the robot stops? Naturally, the cargo will continue moving and this is dangerous. For how long, what would be the energy? All these are things that could be discussed with this robot.
The robot is not completely finished because you have to finish it and decide on the wheels to be used.
After building the robot, close the box to keep the desk clear.
- Gather all the parts from the desk and put them back in the box.
- Close the box and move it aside so it's out of your way.
Programming
Today the programming challenges are much less, compared to the construction challenges. The goal is to both start and stop moving the car without hesitation that it would tumble.
Inertia: The Basics
There are two types of inertia to familiarize yourself with. One you know intuitively, while the other is more obscure. Both must be considered when building your own robots, especially in future competitions.
What is inertia?
In Physics, inertia means that an object in motion will remain in motion, and an object at rest will remain at rest unless some outside force stops or starts the object.
Inertia In Motion
One type of inertia is inertia in motion. You can easily understand this if you imagine running very fast. Are you able to stop immediately? No. Another typical example is when you are cycling and want to stop. You apply the brake, the wheel stops spinning, but the bike continues to move, leaving black rubber strips on the asphalt as evidence of the inertia.
Take a look at an interesting video of a master pilot of a helicopter: https://youtu.be/JKnzzYk4vLo
Is inertia an issue when building robots?
Yes, in many cases, the robots we design can have the wrong center of mass, and the center of mass is crucial for us to have well-balanced robots.
For the robots we design in class, the center of mass is the heaviest part of the robot, typically the brick. In today's robot, the brick is positioned far ahead of the motors, third wheel, and tires. This causes the front of the robot to tilt and even tumble to the ground when stopped suddenly.
There are, of course, solutions to this problem: modify the construction so that the center of mass is correctly positioned within the triangle formed by the robot's three contact points.
In the field of robotics, there are two main disciplines: construction and programming. In some cases, issues related to inertia can be resolved through changes in the robot's programming.
Inertia At Rest
Another type of inertia is where an object at rest tends to remain stationary. For example, consider a plate on a silk cloth.
Do not try this at home: https://youtu.be/nSj_MVUsBzg
A teacher may demonstrate this experiment using a piece of paper and a smooth, heavy object, such as a LEGO motor or an Intelligent Brick. However, we are not responsible if something falls and breaks!
Tasks to finish a class
- Take pictures and make videos of your robots
- Disassemble and arrange the robot
- Arrange your workplace
- It is important to arrange the electronics of the robots on the cover of the box.
- Wind up the programming cable so that it is assembled.
- Put the robot cables next to the electronics.
- Wind up the mouse cable around the mouse.
- Wind up the cable of the laptop charger in a way that your teacher will show you.
- When you turn off the computer, leave it next to the robot box.
- Turn off all programs on your computer
- Exit FLLCasts
- Shut down your computer
- Put your chair under the desk.