Preliminary Detailed Design
Table of Contents
Team Vision for Preliminary Detailed Design Phase
Team's plan for this phase:
- Create test plans to ensure engineering requirements will be met.
- Select the materials needed to make a prototype.
- Create schematics/flowcharts of the entire system.
Team's accomplishment for this phase:
- Created a preliminary bill of materials.
- Updated overall schematic and created schematics for individual nodes.
- Created a software flowchart.
- Created test plans for the engineering requirements.
- Added new risks to the risk assessment document.
- Created a plan for next phase.
Feasibility: Prototyping, Analysis, Simulation
- The autocrop script and the cropped image renaming script will only be able to function on a Macintosh computer; CaptureOne on Windows does not have scripting capabilities.
- Autocrop script:
- A speedy autocrop script is possible. See the youtube video link below to see it functioning; it takes around 1 second per artifact to perform the automatic cropping. Most of this time is spent in the AppleScript; the actual program only takes around ~0.03 seconds to find the artifact bounding box.
- Artifact sizing:
- It was found that automatically sizing an artifact with a webcam is possible. A prototype was created that first sizes an image of known dimensions to obtain a pixel per square inch measurement. In subsequent runs of the prototype, this ppi measurement is used to convert artifact bounding boxes in pixels to a bounding box in inches or some other unit.
The following pseudocode illustrates how the artifact sizing script functions.
The following three images give an indication of how the artifact sizing program functions.
The size obtained for the test artifact. It was printed as x,y. The actual size was 2.4 inches long and 0.75 inches wide.
A simulation was performed in order to estimate the number of images per hour that could be processed with the proposed system.
Process throughput without stopping:
- 1 Hour Throughput: 96 artifacts/1 hour
- 2 Hour Throughput: 195 artifacts/2 hours
- 3 Hour Throughput: 293 artifacts/3 hours
Drawings, Schematics, Flow Charts, SimulationsIn this design phase, the autocropping script previously prototyped was sped up considerably by porting to C++ and making a few design changes. The updated flow chart for the autocrop script can be seen below.
Additionally, once the cropped images are obtained and exported, they will still be named the same as their parents. A script was created to rename the cropped images. The flow chart for this script can be seen below.
In the conveyor design, a rangefinder is placed near the end of the conveyor. When an image is moved over this conveyor, triggering it to halt before it takes a dive off of the belt system. This stopping is not instantaneous, however. The timing diagram below displays the sequence of events leading to the conveyor stopping and approximate delays for each event.
It can be seen from the above image that it will take right around one third of a second to halt the conveyor belt. Note that the times on the diagram are approximated worst-case delays. As such, it is very likely that the conveyor will stop quicker than one third of a second. As the conveyor belt's maximum speed is to be set at 6 inches per second, a 1/3 second delay in stopping the conveyor will translate to a distance offset of roughly two inches; the image will be in no danger of plummeting from the conveyor system.
Bill of Material (BOM)
Design and Flowcharts
Design Review MaterialsThis presentation was created for this phase's design review.
Plans for next phase
As a team, we are planning to finalize all in-progress elements of our design, as listed below:
- Test plans must be fully fleshed-out, and tests conducted if applicable at this stage
- CAD model of structure completed
- Manufacturing methods decided upon for fabricating structure
- Order all items currently on the BOM
- Prototype different elements within the structure
For more information, see our individual three-week plans.