The information shown below represents the major things we have accomplished and/or have been working on up to this stage of the project.
All related documents can be found in this Detailed Design Documents directory.
However, all files that are needed for this stage of the review process are found below in either pdf or picture form.
Prototyping, Engineering Analysis, Simulation
System Base/Motor Mount & Motor Couplings
Drawings, Schematics, Flow Charts, Simulations
Our options for couplers are currently as follow:
- Flexible Drive Shaft
- Helical Flexible Shaft Coupling (clamp-on)
- Helical Flexible Shaft Coupling (set screws)
- High Precision Bellows Flexible Shaft Coupling
- After further research of the slotted lines being used, it has come to our attention that there are several different configurations. This will make it extremely difficult to proceed in MSD II with a prototype that is built for manufacturability of all the linear measurement system assemblies. It is recommended that a common configuration be chosen and all slotted lines be modified to that chosen configuration.
- In order to reduce the potential for misalignment
problems between the motor shaft and slotted line shaft,
the slotted line needs to be secured to the baseplate
with solid (metal is recommended) standoffs that will be
secured into the base plate.
- Currently (on at least one of the slotted lines) all feet are not secured to the base fixture and some are even drilled into the wood which holds the motor allowing for potential misalignment issues here.
- Although it has not been confirmed that the motor is
actually binding as originally believed, there are four
different places (two on the measurement head and two on
the slotted line shaft) where binding could be occurring.
- It is possible that the "binding" we are witnessing is actually a software issue.
- It appears as if the error message that appears in the LabVIEW GUI when the motor stops turning only occurs when the program is set to run at a resolution that is less than the maximum allowable resolution.
- The measurement head and other components along the slotted line are caked with oil and dust/dirt. This could definitely be adding to the mechanical reliability issues and should be addressed. The user's guide for the slotted line states that the components should be cleaned regularly.
- The rods on the slotted line and the rail that the measurement head rides along are only attached by set screws which have the likely potential to come loose, be torqued, and become misaligned.
A summary document for these notes above: Slotted Line Mechanical Discussion
The initial CAD drawings that were made are shown below in the following two links:
The most up-to-date drawings are as follows:
The full system assembly drawing at this phase in the project is shown in the figure below:
- Further research is being conducted to determine the source of the mechanical reliability issues of the system as outlined above.
- If it is confirmed that binding of the motor is occurring and that it is being caused by motor shaft misalignment with the slotted line, testing of the couplings will be completed in order to fix the current system's mechanical reliability issues. A motor mount currently being manufactured in the KGCOE machine shop will be utilized for testing on a temporary base to complete preliminary testing. The chosen coupling will determine how the motor is to be mounted to the system. Special consideration will be placed on price of the coupling along with its ability to maintain motor alignment with the slotted line.
Detailed Design DecompositionIf we go back to the intial work in defining our overall system we find that the following diagrams are of great use. The proposed system level diagram is shown below:
Breaking the above diagram down further we can separate each outcome that must be achieved:
From the above diagram it can be seen that there are four major components to our system. They are as follows (in no particular order):
- PC - MATLAB GUI
- Power Supply
- Microcontroller and Motor Control
- Mechanical Coupling of Motor and Slotted Line (and base design)
The first proposed Detailed Design level wiring diagram is shown below:
The correct proposed Detailed Design level wiring diagram is shown here in pdf form for easy viewing:
Changes that have occurred since the last review include a new selection of power supply and motor needed for our application. These changes are listed below:
Breaking the Final Microcontroller Wiring Diagram down further we can represent it on a circuit schematic level as shown below:
MATLAB Network Analyzer Data Acquisition Code
Drawings, Schematics, Flow Charts, Simulations
The initial flowchart for the MATLAB GUI is shown below:
The revised version is as follows:
Test PlansTesting this system will involve using the previous halfstep.vi program as a reference. The results from this program will be compared to the results of the MATLAB program. As per our customer requirements, the results need to be equivalent.
Drawings, Schematics, Flow Charts, Simulations
From the first Detailed Design Review the following two charts were shown:
Below is an initial incorrect explanation of the code for microcontroller:
The next initial code flowchart which is slightly more accurate to the final implementation is shown below:
For this flowchart shown above a timing diagram explanation for this code would be largely as follows:
Timing Diagram Explanation - This timing diagram and explanation is no longer correct and should not be referenced for an understanding of actual project implementation.
It was found that after a more through examination of the interaction needed between the MATLAB GUI and the microcontroller code that the "timing" that needs to occur is within the code. This issue of timing is solved with while() loops that wait for a response from either the GUI or microcontroller depending on what response is needed.
The final code flowchart which represents the code that has been written thus far is shown in the file below:
The appropriate code for this flowchart above is shown in the Test Plans section below:
Initially, the coding that will need to be achieved will expand upon the previous code used in the Subsystems Design phase of the project:
This code will be expanded upon by the tasks listed below:
- Write code to send the motor one direction a set number of steps.
- Define the above code for the exact distance that
needs to be traveled.
- 1000 steps (@ 0.05 cm/step) = 50 cm
- Develop a rudimentary interface with MATLAB to collect distance traveled data from the Arduino Mega 2560 for the GUI plot.
It should be noted that the programming that will occur for the Arduino Mega 2560 will be done in the Arduino Software (IDE). This programming environment is shown below:
The coding that has been achieved thus far is found below:
Overall Test Plan of Full System
Bill of Material (BOM)
Our Bill of Materials as it currently stands is shown below:
This table is subject to change. Any information currently excluded from this table is due to the fact that unforseen needs may arise due to the Detailed Design Review and to the upcoming work that will be done on the project.
Our proposed budget for MSD II is shown below:
Schedule and Risk AssessmentOur initial proposed schedule for the final weeks of the semester with the associated major events was detailed below:
As of the final review a schedule of events is no longer needed for this semester. For the next semester we have attempted to map out how we propose to break down the work we have to do in order to successfully complete the project. This is shown below:
At this stage in the project it has been determined that the following table is a more up to date and accurate description of the project risks:
In addition we have also updated our engineering requirements to meet this stage of the design process. These requirements are found below in the following pdf:
We have also created a our proposed build/test plan based upon all the information given above:
Post Detailed Design Review Notes - PART 1/2
Microcontroller Circuit Diagram
- Would like more of a schematic than a wiring diagram of electrical components
- Low pass filter from switch to microcontroller
- Show Arduino's wiring diagram on ours so that we know what the codes mean-ex: what is D05 on the Arduino?
- Show third wire to wall-ground
- Timing diagram with stepper
Microcontroller Code Flowchart
- What starts the code?-->PC on
- When you plug in USB, not when you turn on the power supply
- More detail
- Timing diagram
- Turn on power supply
- Stepper motor returns to home position switch
- Show actual inputs and outputs that are happening
MATLAB Code Flowchart
- Must display SWR data AND plot data
- Motor steps .5 mm each time
- "half step"
For Thursday 4/23/15
- Kate-order base plate materials now
- Cheng-order a plastic enclosure (with vents) for components
- Matt & Will-Timing diagram for microcontroller and MATLAB
- Will-Modifications to the DDR Wiring Diagram and Creation of a schematic
Post Final Detailed Design Review Notes - PART 2/2
- Update revision number and date on the wiring diagram
- Add high resolution/medium resolution (Dr. Venkataraman is considering this as an option for the GUI – she will let us know), add dual plotting, prompt user for name of file for .txt file holding the collected data, add safeguard timeout for bringing the measurement head back to home position, reverse axes on GUI
- Move home switch arrow on your flowchart, work with Matt on implementing the safeguard timeout issue
- Check spacing on rods that measurement head rides on,
software issues stopping measurement head?
- We are clear to perform the discussed modifications and cleaning to one designated slotted line in order to try and remedy the mechanical issues present.