Lab 11

Date: 10.05.2012
Duration of activity: 3 hours
Group members participationg: Jeppe, Stefan and Thomas

Goal

Today we have to settle on an end course project.
We have already discussed some potential projects and we will go through them in this lab report.

Plan

1) Compile a list of potential end course projects, and a description for each of them.
2) Choose a project and
3) motivate you choice
4) give a detailed description of the chosen project as outlined below:

4.1) Hardware / software platform and software architecture.
4.2) Point out most difficult problems to solve in the project.
4.3) What we are able to present at the end of the project period.

5) Include a plan for your work with the end course project

Results

1) Project idea list

• 1.1) A group of robots learning a language
  The idea is inspired from how groups of humans build language over time.
  World:
  A static world consisting of various objects identified by color.
  The robots will move around some what random on the map.
  
  A) When a robot encounters an object that it has not seen before,
  it will come up with a sound identifying the object.
  
  B) When two robots meet they will "have a conversation" (exchange some of the sounds for the objects that they have encountered in the world).
  If two robots have seen the same object, they will most likely have two different "words" for the objects.
  
  They want to try to agree on the word based on a probability function, where the likelihood of a robot A using a word from an other robot B is defined by a function of the number of times it has already shared a sound for a word.
  I.e.:
  Robot A tells robot B: "I have shared my sound for this word 3 times",
  Robot B will answer: "I have shared my sound for this word 0 time".
  Thus the sound used by robot A, will now also be used by robot B.
  
  Over time a shared language will emerge. However the language might be split in groups so several languages might appear.
  
• 1.2) Collaborating robots. Inspired by J. Fredslund [2], our idea is to define a task that is to be solved by a group of robots. We considered a task where the robots would have to climb on top of each other by simply driving on top of each other. Once on top of each other, they would have the proper height needed to take down some object. After this the robots would have to climb down again and move the object to some goal which again would require the robots to climb on top of each other.
  
  
  
• 1.3) Measuring of a room by many robots
  We want to investigate how fast and efficient multiple robots in cooperation can measure different types of rooms. A room could look as in the sketch below:
  
  
  From the collected data we have to be capable of making a 2-dimensional sketch of the room.
  The robots will send their data to a central computer which will use the data to generate a complete picture. Either the central computer will guide the robots or they will be autonomous.

Project	Difficulties
A group of robots learning a language	Detecting when two robots meet each other. Either the robots will have touch sensors to detect when they bump into each other or maybe they could have a distance sensor as a "radar". The robots will have to know how to communicate with the right robots. That is, if robot A bumps into robot B, A have to find out who he really bumped into.
Collaborating robots	Construction of the robots. Making the robots find each other and align them self. Climb up on top of each other. Climb down again. Catching an object could be difficult, especially due to the alignment toward the object.
Measuring of a room by many robots	The idea is that the robots do not know where they start and will have to deduce this from the world. Thus navigation will be a challenge and the track could be constructed such that the robots have some kind of fixed point to navigate from. Communication for cooperation for a optimal solution. That is, the robots should work together on scanning the room rather than scanning areas that has already been scanned.

2) Choose a project

We have decided to go ahead with the "Collaborating robots" project.

3) Motivate you choice

We liked the idea of collaborating robots and thought that the idea would contain a lot of exciting challenges. As outlined above in the table there are many difficulties to overcome.

4) Give a detailed description of the chosen project

We have specified the task that the are to be solved a bit more in details: The track consists of a tower with an object on top of it. The object must be fetched by the robots and put in a high basket. The robots have to climb on top of each other to fetch the object. Then they will have to climb down again in order to fit under the bridge (or tunnel). Before the ball can be placed in the basket
 the robots have to climb on top of each other again.

4.1) Hardware / software platform and software architecture.

The hardware will be 3 * NXT with one or more light sensor(s) attached to each along with two motors.

4.2) Point out most difficult problems to solve in the project.

See the table above.

4.3) What we are able to present at the end of the project period.

Three robots finishing the track outlined above.

5) Include a plan for your work with the end course project

Initial plan for the end course project.

1. Build a track.
1. Find a board for a track
2. Collect materials for the track, paint, glue, wood etc.
2. Build the robots.
1. Tow stacking bots.
2. One grabbing bot.
3. Initial program
1. Make the two stacking robots climb each other.
1. Make two robots climb down again.
2. Make three robots stack each other.
1. Make three robots climb down again.
3. Make the grabbing robot drive off the two stacking robots below and grab the object on top of the tower.
1. Make the grabbing robot drive back on to the two stacking robots.
4. Make all the robots follow the black line on the track to the basket.
5. Make all the robots climb each other again and make the grabber robot drop the ball in the basket.

Conclusion

We have discussed three ideas for a end course project. We agreed on following the idea with the collaborating robots solving a task together on a track.
We described the initial requirements for our robots and the initial track.
An initial draft for a project plan have been made. This plan will be revised next time we meet if necessary. 

References

[1], Lab 11, http://legolab.cs.au.dk/DigitalControl.dir/NXT/Lesson11.dir/Lesson.html
[2], J. Fredslund et al., http://legolab.cs.au.dk/DigitalControl.dir/journalpaper.pdf