Introduction
In the previous lesson we've learned that the wheels of the car are rotating with different speed when the vehicle is making a turn and that is the reason they cannot be connected to the same motor. But what if we connect only one of the rear wheels with the motor and we leave the other one free?
Today we're experimenting with a truck that is designed to transport cargo through rough terrain. The focus here again is on the construction. Hopefully, you've learned to park in the previous lesson, because you may need it again!
Construction
Today's vehicle has a similar construction to the previous, but with one big difference. The motor is connected to only one of the wheels. The goal of this construction is to make the rear wheels travel at a different rate while turning and to eliminate the rear axle vibrations of the truck.
The construction connecting the front wheels of the cars is called a front axle, and respectively - rear axle for the real wheels.
The truck's trailer is open from the back. Would you carry a cargo through rough terrain with an open trailer?
If the answer is NO, then make this trailer a barrier.
If the answer is YES... then make the barrier after you've collected the scattered cargo and paid for any damages!
Mack - Truck built from LEGO Mindstorms EV3
Instructions for building a LEGO truck. We use a medium motor for steering and a large motor for driving one of the rear wheels.
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 robot has to be able to move through rough terrain.
In order to get that bumpy terrain, put some LEGO parts into the lid of a LEGO Mindstorms box and program the truck to make different maneuvers through it. Be responsible and careful - all the parts have to stay in the lid of the box! Remember that otherwise you'll have to collect them.
Slipping
We say that one car is slipping, when its wheels are spinning, but the car isn't moving. This happens when the wheels of the car are on ice or in mud. Due to the differential gear structure, the wheel that spins the most has the least resistance. This means that if one of the driving wheels hangs in the air or happens to be on ice, it will start slipping, while the other wheels are not moving. This is extremely unpleasant, especially if it happens to a heavy vehicle.
We already know what is slipping. Let's see if our truck would have such problems.
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.