Video tutorials -

• FIRST LEGO League 2016-2017 Animal Alias

Time to lift the robot. The first approach is by using the 40 teeth gear wheels that come with the LEGO Mindstorms EV3 and NXT robotics sets. 

Build a robot base to use in the course. You can use the robot base provided by us or you can build one yourself. 

Build a similar mechanism to this one. Similar, but for your robot. This is the task for you. Try, give yourself half and hour or even an hour.

Connect the attachment to the box robot and find the correct number of rotations of the middle motor that would bring the robot up and forward and would attach it to the mission model.

Remember the passive/active attachment separation that we are making at FLLCasts.com. This applies for all the attachments and in this Episode, we are looking at how to use a passive attachment.  

How great is the great attachment for lifting that we built in this course? How many times can it lift the robot without making an error? How great are your attachments and how could you test them? - the answer is simple. Just try 10 times and they should work at least 9 of them as our attachment is.

How to align the wheels and how much should you push for this solution?

What is the end result? - have the attached on the mission model. What is the mechanism the would make the robot hang on the mission model.

There were a few problems with the 40 teeth gears that we were using. Let's list some of them

Think of an attachment that leaves the Gecko on the mission model. Don't use the robot attachment that we already have. Just the box robot and the gecko. Nothing should support the Gecko when it is hanged on the mission model. 

In this tutorial, we add another mission to our current program. This mission is - hanging the Gecko from the FIRST LEGO League Animal Allies. 

We calculate the number of rotatios when a gear system is involved. The driving wheel will have to do a number of rotations for the driven wheel to rotate to a desired number of degrees. In our specific case when the driven gear wheel is rotate to about 90 degrees the legs will lift the robot.

This is a teacher's note about the math behind calculating gear ratios with for our lifting attachment. It math model we build in previous tutorials is not exactly correct and here is the explanation why.

The task in this tutorial is to execute the program 10 times and to do it yourself. If you have your attachment then use it. If you have our attachment then use it. But execute the program 10 times and make sure that it works. 

Sometimes the answer that you get by calculating seems not to be right. Is it the calculation that is wrong. Probably it is not the calculation, but something is happening with the robot. 

Let us do a quick recap of the whole lifting mission and its solution

If you've done the calculation following the previous tutorials you would arrive at a result of 18.75 rotations. But this is not the correct answer. The calculation is wrong, because the math model that we've built, although kind of obvious, is not correct. When experimenting the correct number of rotations would be 37.5. This is a large difference. Two times larger. Exactly two times large. Something should be happening here - and this thing is "planetary mechanism"

Calculate the number of rotations you have to do with the motor to rotate the final small 8 teeth driving gear wheel to 1.25 rotations?

What should you as a teacher know when the students are trying to achieve a program and robot attachment that could reproduce their behaviour 9 out of 10 times. 

In this video we discuss the durability of the construction of LEGO robots and how do we make them more durable. 

What should you do as a teacher when the students are calculating the gear ratios and number of needed rotations?

Note for the teacher on making the construction more stable, more durable and using beams for this.

In the previous video, we found the correct answer for our task and it is 18.75, or is it?

Following the principles from the previous video, try to make the attachment that you've built, more stable and durable.