Don't limit yourself to the box and think of different ways to lift the robot.
- 06 Mar 2017
- LEGO MINDSTORMS, LEGO MINDSTORMS EV3
- Lift, FIRST LEGO League, Box Robots, EV3, Construction, Classes with students, FLL
Weight and size
The lighter the robot the better, but you would have fewer parts. You can work with a third or fourth motor, but this will make the robot heavier and probably more difficult to lift.
Center the gravity
The closer the center of gravity is to the mission model the easier it will be to lift it. The center of gravity is the point of the robot body on which if you place the robot it will balance and will not move.
The center of gravity is in the middle of the robot and it is easier to use it. This is by design, but if you have the center of gravity closer it will be easier to attach to the mission model.
The robot base for lifting and attaching on the mission model. In real life the mission model will bend. And that's for sure. We can't make it that stable. Don't limit yourself by the box and try to think of different ways to do the lifting. Here we have our general Box Robot. First thing to know about this robot is the size and the weight of the robot. It is normal that it will be difficult to lift a heavier robot. So, a lighter robot will probably be easier but you won't have that many places to attach the attachment, you won't have the third motor. So, it's a balance. The next thing is that the size of the robot also matters. If you have a very large robot, it will be very difficult to attach this robot to the mission model. And there is one more third thing and this is the center of gravity. We must consider the center of gravity for this robot. And the closer the center of gravity is to the attachment, the easier it will be to attach this robot to this attachment. So, when looking at your robot this can be the front but you can attach the robot from the back. You can attach the robot like this. Or you can even lift the robot and try to attach the robot like this. You can think of such an attachment. There is no need for the robot to be horizontal. You can even make the robot be vertical. And it is like this. Or you can think of any other type of configuration for this robot from the 4 different sides and up and down. For our Box Robot one of the very good things about this robot is that the center of gravity is just at the middle of the robot. What is the center of gravity? It's the point on which if you place the robot, the mass of the robot will balance. And how do we find the center of gravity for this robot? There are different ways but I'll just use this system of beams, place it here and if I now place the robot and if the center of gravity is just above the beams, the whole robot will balance. You see that now it goes to the back. So, I'll move it to the front and a little more and a little more and it is somewhere in-between. I'm not sure if I'll be able to balance it for the camera but I'll try. Like this. And you see that the beam is just at the middle. So, our center of gravity is at the center of the robot. That's not bad. That was a designed decision for this robot to have the center of gravity like this but if you have the center of gravity closer to the attachment it will be easier to attach. Why? Because then when you attach the robot if the mass is located closer to the mission model, then it will hold the mission model and it will not bend. And if you have most of the mass located away from the mission model, the whole mission model will bend. Because it's working like a lever and it's pushing on the mission model and if the mass of the robot is here, it will push and it will be difficult to lift it.
Try to find the center of gravity of your robots and if you've build the Box Robot again do the experiment and find where exactly is the center of gravity of this robot.
Courses and lessons with this Tutorial
This Tutorial is used in the following courses and lessons