Collecting humans. Moving modules. WRO 2014 Elementary. Part 3 - Lifting

In this last part of the tutorial we actually lift the rocket modules and prepare them for lauch. First we have to collect them in the right order and them somehow lift them.

  • #182
  • 09 Dec 2015
  • 9:43

Picture of the grabber with the robot

Below you could see the field of the World Robotics Olympiad (WRO) 2014 Elementary challenge. The blocks must be collected from the yellow regions.

Elemntary field for the WRO 2014

For this robot we use a grabber developed by Dave Brauer. We just extend it and modify for this robot. Check out the materials section. 

The grabber uses one motor to achieve two movements. On for moving the grabber and one for actually grabbing. This one motor, two movements is a very powerful. More video on the subject you could find by searching at for one motor, two movements.

Previous video tutorials:

Collecting humans. Moving modules. WRO 2014 Elementary. Part 1. Rocket Elements

Collecting humans. Moving modules. WRO 2014 Elementary. Part 2. Humans

WRO Robot Grabber from LEGO Mindstorms EV3

Building instructions for a Robot Grabber used in the World Robotics Olympiad competition runs. The grabber is build with LEGO Mindstorms EV3

WRO Robot Programming

EV3-G program developed for the World Robotics Olympiad robot runs. In collects, moves and lifts the modules


We placed the modules of the rocket, we launch them, we also collect the humans and we clear them from the area and now the subject of the video is how do we catch and move these modules, with our robot.

We have the three modules and we have our robot, it has an attachment on the front, this attachment is powered by the medium motor. You can find more about this attachment below the video. You can find also the building instructions for this attachment and this attachment works in the following way. I start the motor, and I can move the attachment up and down and while moving it down, we also open the attachment.

Now as we move on the field, we can move to one of these modules, it doesn't need to be very precise, we move to one of these attachments and we can catch it with the motor. The next step is to lift the module, the rocket module.

We catch and lift the module. We can stop right here and we can move, over the humans. Then we move, we collect the humans and then we can return the whole module and push it to the rocket launcher with the same attachment. If we now reverse the motor and we can return and place it back.

What's interesting about this attachment is that you have 2 movements with one attachment. You move the attachment up and at the same moment you catch the rocket module. These are 2 movements with the same attachment.

So we have the basic building blocks for solving the World Robotics Olympiad 2014 elementary challenge. We know how to catch these modules, we know how to lift them, we know how to move them. We also know how to collect the humans and we know how to position them on the rocket launcher. The next step is just to position yourself on the field. Let's do a couple of runs there.