Constructing BigDaddy Competition Robot (Part 2 - Front) Pro Preview

Based on your feedback we have decided to show you the live process of building a complex LEGO Mindstorms Competition robot without having the whole robot ready yet. We are continuing from part 1 where we finished part of the 'front' of the robot and we arrived at a construction that we didn`t like and would fix in this video lesson.

  • #71
  • 15 Feb 2015
  • 5:33

The Name

Yes, we have watched the Marvel 'Kick Ass'. And yes, this robot will be big and angry.

The Construction

The robot construction has a 'front', 'back' and a frame in between. In this video lesson we are working on the 'front' where we use a paired gear wheel. The power would be transfered from a mindstorms motor to the front wheels.

The Frame

Continuing from BigDady Competition Robot (Part 1) we add a frame that could be used to align the robot to walls which is a technique successfully used in easy robotics competitions.

The Process

We construct, experiment and post. You give us feedback and based on the feedback we make modifications on the robot. So, build it with us on the way, try to take up a specific challenge with it and leave us a comment below on what has and what hasn't worked for you in this robot.

Other episodes from the series:

Constructing BigDaddy Competition Robot (Part 1 - Front)

Courses with this episode

The episode is used in the following courses where you can find additional tasks for it to use in class

Big Daddy

Construction Innovation is again the task for this robot. Use the task in your classroom, for your team or at home to engage students in learning. 

There are 3 task from an normal, medium, hard complexities giving 1, 2, 3 points respectively

Tasks description, submission and evaluation are available to subscribed users.

Subscribe now to access the full capacity and get feedback.


In the previous episode we finished constructing a very interesting front part of a robot with two wheels. We can transfer power from the motor to the wheels and achieve a very stable movement. In this episode I'd like to build something on the gear wheel that we could later attach the motor to.

Now that we have this gear wheel, we should find a way to add additional holes on which we can continue the construction. The holes of the gear wheels are placed horizontally and it's very convenient to add this frame on top of the gear wheel so that we can have more holes. For example, horizontal and vertical, on which we can continue the construction. In order to add this frame to the gear wheel, I'll show you a way with two black pins that's kind of difficult but interesting. Watch carefully. Now. It will be very stable but first we add one of the beams, then we add the other and now we have the construction. If we add one red pin to the other side, we'll get a very stable construction. But it's difficult to construct and it's even more difficult to remove it. Another way is to add the frame with the red pins only. So, I'll remove this axle from here, I'll add the red pins. The order is very important - first one of the sides, then one pin on the other side,

then on this side again

and then we add the frame. After adding the frame, we can just push the red pins and we have the frame attached to the gear wheel. We can use these interesting special LEGO parts that are available only in the EV3 Mindstorms set that are not used very often but will be very useful for own construction. We add them to the frame. Like this.

And this one here. And we can continue from here with improving the construction so that we can attach a motor and probably the back of the robot or the front. (We still haven't decided whether this would be the front or the back.) Something that should be mentioned is that this construction is not very stable with these two parts because it bends, as you can see. That's why we should add one additional beam on this side of the robot. And in this way we'll prevent the parts from bending. We've achieved a very, very stable construction that can transfer the power. Now we can again add the axle and turn the wheels. The last step of our video is to actually add a frame around the wheels and the construction. This frame, as you probably know from other videos, is very useful as you can align the robot to different walls. You can see the instructions for adding the frame in the materials section below the video. I've already prepared the frame. I'll add one of the frames to the back part of the robot. Like this. Then I'll add the large frame (it's mainly constructed from beams and angled beams). I'll add it to the front. Like this. There are four pins that we should attach. One, two, three, four. Then from the back - as you can see it's very modular. We add just two modules and we have the frame at the front ready. As to the wheels, you can see they are connected very loosely. We should add additional parts, so that they are more stable.

Each axle should be connected to least two points. One is ready.

And the second one is ready. In the next video we'll continue with improving the front of the robot and adding a motor, a back.. Let's see what will come out of this construction. Leave your comments below and we'll be happy to hear from you.