Friday, 12 December 2008

End-project. PART IV

Date: 12 12 2008
Duration of activity: 2 hours
Group members participating: all group members

1. The Goal

The goal of this lab session was to agree on the main points of the architecture and make some adjustments with regards of the LEGO structure.

2. The Plan

  • Agree on the architecture.

  • Further upper carriage construction.

  • Adjustments of the sliding part.

3. The Results

3.1. The architecture

The first thing that we have done during this lab session was agreeing on the architecture. As it was mentioned before, in this project we will use a layered architecture. It is very important to leave as much space as possible for scalability and modifiability as for now it is not exactly clear how much of each layer we will need to use. The things we have agreed upon for now, looks like this:

4. Input handling. (tentative)
3. Input (vector) interpreter. (tentative)
2. State calculating navigation layer. Possibly feedback giving. (tentative)
1. X-Y movement calibration (mm wise). (definite)
0. Motor speed and tacho count handling. Re-zeroing. (definite)

3.2. The carriage

The second thing to do in this lab session was to mount the upper platform (the carriage) with two touch sensors. Whenever a touch sensor is touched on this platform, it indicates that the Y-axis is at its very beginning or at its very end. We couldn't get our hands on the standard official LEGO grey touch sensors, so instead, we have to use a couple of semi-transparent blue third-party ones. For now, the upper platform with such a sensor looks like this:

3.3. The sliding part

The third thing that was done in this lab session is a very important one. We have made the support near the spindle-axis more smooth. Also, we re-built the part that is responsible for the up/down movement in a way so it pushes the Y-axis-spindle more from outside-in, which is to say, it gets pushed into its support structure now, as opposed to being pushed out of it, before. By pushing the axis inwards that way we get more support for the axis and the movement along the Y-coordinate axis becomes more stable and does not get stuck.

4. Conclusion

The benefit of this lab session is that we now exactly agreed which layers of the layered architecture we are planning to use. Also, we mounted the carriage with two touch sensors and made the sliding part travel from one side to the other more smoothly.

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