RIT will permanently shut down the RIT Wiki (Confluence wiki) on February 2, 2024. Review the Wiki Shut Down Overview for information on alternative tools, exporting content from the wiki, and other FAQs.
Team Vision for Subsystem Level Build & Test Phase
Summary:
- On the mechanical side, we planned to finish building the solar module as well as test it and begin building the scissor module. On the electrical side, we planned to finalize CAD models and start fabrication of the electrical box. For both the mechanical and electrical, we planned to hit roadblocks and redesign as necessary.
- On the mechanical side, we finished building the solar and scissor modules and began testing on both. The electrical box CAD models were finished, and the acrylic was cut from these models. The electrical box as been assembled and is ready to be wired.
Purchasing Update
Nearly all outstanding orders have arrived for both Mechanical and Electrical BOMs
Only one item remains
Neodymium magnets (renewable BOM)
Contacted vendor for backorder status
Solar Module Build
Tackled the Solar Module first due to order of parts machined
First attached the hinges to the panels to ensure hole location
Next we assembled the enclosure of the solar panels
Started with hinges to attach base to side flaps
Attached rubber “clips” to hold flaps in place
Then creatively used the MSD tables to secure solar panels to enclosure
Needed to enlarge holes in the enclosure slightly to secure solar panels
Solar Module Build Issues
Hole alignment and hole access were small struggles. We mitigated these problems by enlarging a few holes slightly to ensure assembly would be successful
Had to work around the Plasma Cutter being down and not functioning
Scissor Module Build
Machining
Second priority to solar module
Parts fabrication order came from:
Where they needed to go next
Finished designs
Available material
Welding
Had welding done as soon as parts were available for each drawing
Worked with Gary to make sure design priorities were clear
Hole-to-hole dimensioning for better alignment with sheets
Sub-Modules
Upper
No adjustment needed
Lower
Slight hole adjustments
Arms
Slight positioning change on roller ends
Bolts VS. Welds
Easier to make slight adjustments with bolts
Full Module
Attention to detail paid off
No major changes needed
Scissor Module Build Issues
Sliding
Not the smoothest slide when changing height
Changed washer positions to give roller more clearance
Wobble
Slight wobble with lateral force to module top
No change currently needed
Thumb Screws
Heads were too big
Trimmed without losing functionality
Electrical Module Build
Acrylic pieces have been laser cut and assembled
Minor hole adjustments have been noted
Display panel is being fabricated in tandem with box
Close to wiring components
The screw holes align and clearance is good
Angle brackets make the box structurally suitable
Footholds align with scissor module
Acrylic is very clear and easy to see through
Electrical components are receiving minor tests to verify functionality
Code repository has been initiated on github with some SW written
All displays work with I2C interface
Electrical Module Build Issues
Some components don't fit and need more clearance
Acrylic panels will have to be modified
Multiple issues with vendors led to two slightly different thickness being used for acrylic
50 amp current sensor got rather warm during low current test
May affect max power test
Test Results Summary
Pick up and Move Test - Engineering Requirement 9
Outcome | Weight |
Required | 30-50 |
Results | Both Modules within Range |
Solar module: 48 lbs, Scissor module: 46lbs with wheels, 26 lbs without Wheels, Wheels 5 lbs each.
Physical Load Test - Engineering Requirement 17
Outcome | Weight (lbs) |
Required | 50-100 |
Results | Top held 70 lbs, Bottom held 130 lbs |
The top of the cart held 70 lbs, Bottom held 130 lbs (Garrett).
Sizing Test - Engineering Requirement 10
Outcome | Pass/Fail |
Required | Pass |
Results | Pass |
Scissor: 12.75” height, 30” length, 23.75” width, 5.6 ft3
Solar: 7” height, 31” in length, 24.75” width, 3.1 ft3
Electrical Box: 13” height, 15” length, 13” width, 1.5 ft3
9.8 ft3 total combined volume
Risk and Problem Tracking
Risks
Seven risks, 10,14,19,24,31,32, and 35, were modified, and one risk, 36 was added. These changes can be seen below and the rest of the risks in the following document: Updated Risks MSD II .
The likelihood for risk 10, the previously purchased equipment not functioning properly in assembly, was decreased from 2 to 1. We have incorporated previously bought material into our design and it is working well. The severity of risk 14, the cart may not be durable enough, was decreased from a 3 to a 2. We tested the physical loading of the top and bottom tables and they held the desired weights. The severity of risk 19, cart collapsing mechanism does not work properly, was decreased from a 3 to a 2. This system was tested and it works; however, it will be further optimized. The likelihood of risk 24, cart requires two people for set up, was decreased from a 2 to a 1. We tested picking up and moving all subsystems and they were all below the desired weights and were easy to lift; however, the severity was raised from a 0.5 to a 1 because the corners are sharp and this could be an issue. We will make the systems safer to pickup and move. The severity of risk 31, choosing a non adequate roller and track system, was decreased from a 2 to a 1. Our design is currently working. The severity of risk 32, choosing a non adequate hinge system for solar panel folding, was decreased from a 2 to a 1. Our design worked and we slightly modified it by adding in rubber stoppers. The likelihood of risk 35, necessary design changes push us behind schedule, was decreased from a 1 to a 0. We fixed the welding problem and the physical system now works and is almost finished. We added risk 36, wobble of the scissor system will deform the scissor arms. The likelihood is low, but there is a slight wobble. The severity is a 2 because a wobbly cart would lower the stability of our design. The likelihood of risk 18 has been reduced to 0, the electrical design has been reviewed and verified that this will not be an issue. The severity of risk 21 has been reduced to 0, with the electrical schematic finalized, the modbus protocol no longer affects our implementation. The likelihood of risk 30 has been reduced to 0, the charge controller has been verified to prevent overcharging of the battery and a cutoff switch has been added to prevent over discharge.
Problem Tracking
The problem we were tracking in the previous phase involving the plasma cutter has been resolved. We were able to work with the machine shop staff to get the cutter working and get our parts made.
Links
Plans for next phase
In the integrated system build and test phase, we will work towards finishing the assembly of our cart and work through our test plans to prepare ourselves for a functional demo of our project.