LEGO Caster wheels

In this video tutorial we will show you three ways for making your robot stable on the field. We will present each one of them with their advantages and disadvantages - it's up to you to choose which one is the best for your case.

  • #15
  • 11 Apr 2013
  • 3:55


You probably have seen caster wheels on shopping carts, chairs, etc., but can we use them in NXT robotics? I will tell you today. Every competition robot needs a set of anchor points, other than the motorized wheels in order to be stable. Today, I will show you the most common types of anchors and of course, their pros and cons.

One pair of caster wheels That's the most basic type of caster wheels. The building instructions could be found at the link in the description. Some pros are that these wheels are really really maneuverable, which helps in a lot of situations, because they are turning 360 degrees. Of course, they could be built really easy for less than a minute which is also a great thing. I will now present to you the disadvantages of the caster wheels. There's a slight deviation after exiting a turn. I can show you in my little program here. The robot goes straight and then turns left so do the caster wheels. To go backwards or forward, the caster wheels need some distance to straighten up. This could be a huge disadvantage on the competition mat. Another disadvantage is that, if the robot gets too heavy because of plugins and/or structure, they could be bent. This will cause the robot to lose balance. A quick fix for the loss of balance two pairs of caster wheels. This idea is similar but the solutions is better for heavier robots which need better balancing. If you turn hard with one caster wheel paired up the heavy bot is going to lose control. Like this the force is defined equally to the caster wheels. Advantages: Your robot actually has better balancing and the thing we got from the caster wheels is the maneuverability and it is fast for building. The disadvantages: Our problem from the first chapter is now mutiplied by two. Now the deviation is twice greater because we have two pairs of caster wheels. Now that we have seen those 2 ideas, which pros are less than their cons. I could present you the solution, which most of the competitive teams use. No caster wheels By using this method we guarantee ourselves that deviation cannot occur. Because we use stabilized parts, which do not move, as you could see. I am only going to show you one of the ideas you can use. Try to use your imagination to figure out new and better ideas for this particular problem. It doesn't matter if you use one stabilized wheel, or a studless part, or something else. The pros and cons are similar. Now as you have seen all those methods, you can try use them on your robot and see if they work for you. Hope we see you again.

Courses and lessons with this Tutorial

This Tutorial is used in the following courses and lessons

Image for FIRST LEGO League Competition. Constructing and Programming a Robot Base
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Image for Constructing a robot base
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