All the documents for this phase are in the Detailed Design Documents directory.
Team Vision for Detailed Design PhaseWith major strides being taken in the last design phase, we were looking to end the semester and MSD1 properly. In order to do this, we needed to create a real wooden coil and develop our plan for MSD2.
With great hustle and, at other times, patience, all of our real wooden coils were assembled. Additionally, our MSD2 plan came together showing how we speculate next semester is projected to, ideally, happen.
Drawings, Schematics, Flow Charts, Simulations
Revised Cutting PicturesWith the realization that out previous sketches were not optimizing our wood use, we went back and redid the cut patterns. With more plywood research, we also updated the size of the plywood. This resulted in us needing to buy less plywood and save money. Each sketch is for each piece of plywood, respectively.
Prototyping, Engineering Analysis, Simulation
Wood SelectionWe opted for two .25" x 60" x 60" pieces of baltic birch plywood. This wood was chosen for the following reasons:
- Conveniently sized to allow for cuts needed, while minimizing waste
- No voids
- Multiple plies at such a thin thickness (5 plys)
- Reasonably priced for our structural demands
- Due to the CNC machine having trouble finding the 'zero' on a 60" x 60" sheet of plywood, we had to halve it
- The following pictures are of the wood being cut by the panel saw
- After both the plywood and drawings were halved, the revised sketches were reformatted for the CNC (.tab files)
- The CNC used was a ShopSabre CNC Router 4860
- As we can see in the pictures below, the pieces came out with a lot of rough edges and unwanted wood hanging from it
- 200 grit sandpaper was used to clean off all of the pieces
GluingThe following pictures overview our gluing process
- The two halves were glued at the corresponding edges to form a full circle
- One the face oriented towards the ceiling was then covered in a layer of glue (below)
- The exposed glue was met the corresponding faces of the other halves, in an orthogonal manner
- The coil was then weighed down with various objects to prevent any movement and to ensure additional, constant pressure was applied (below)
- A finished, inner coil (below)
- In order to complete the coil, the outer layers of the coils needed to be constructed
- A completed coil
- All of the coils, completely constructed, stacked concentrically
- Our best efforts to create an isometric view of our structure
Painting & SandingNow that our coils are assembled, we need to sand off glue residue and apply two coats of our spar urethane to finish the job.
Wrapping (Proposed Method)
- Wrapping will be done in MSD2
- Below is a picture of out prosed method using a spinning chair as a means to hold our coil and spin it both consistently and accurately about an axis
- By using a stable axis to spin about, we can pay more attention to regulating both the tension and alignment of the coiling wire.
Bill of Material (BOM)
This is the most recent BOM. The most significant change is that the plywood has been purchased.
Design and Flowcharts
This is the proposed circuit to give the coils the full range of voltage. Ideally, double pull double throw relays would be used to switch both coils using only one input, but for the relay boards available that are compatible with the Arduino, they are limited to single pull double throw. It is important to note that the coils will only switch when the voltage on them is zero. Due to this, any inductance can be ignored.
- 5V 8-Channel Relay interface board, and each one needs 15-20mA Driver Current
- Equipped with high-current relay, AC250V 10A ; DC30V 10A
Magnetometer DevelopmentWe were granted access to use a calibrated magnetometer in order to further verify our method of calibration. Unfortunately we were unable to obtain correct readings from the calibrated magnetometer in relation to what we were expecting. As we were in a lab with a lot of metal and electronics, we are inclined to believe the exhibited error was due to the local environment.
This is the risk chart with minor updates.
MSD2 PlanTasks for next semester include:
- Finish woodworking/painting (if needed) (Week 2)
- Wrap coils with wire (Week 3)
- 3D print parts (Week 4)
- Complete assembly (Week 5)
- Software development (MATLAB) (Week 1-10)
- Execute tests (Week 8)
- Integrate CubeSat/magnetorquer to legitimatize software (Week 11-12)
- Develop 'white paper' (Week 13-15)
Plans for next phase
Before the end of the semester
- Sand coils (to rid of glue residue)
- Apply two coats of spar varnish
- Double check standing with any ordered parts
- Leave work bench clean and organized
Beginning of next semester, as a team
- Finalize details for our wrapping Technique
- Wrap the coils
- Detail means to hanging CubeSat
- Further research opportunities to 3D print our pieces
- Research if particular adhesive is needed for Polylactic Acid (PLA) to plywood bonding
- Software development using MATLAB
- Intefacinging Matlab with with the Arduino and power supply
- Construct and solder the circuits