Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Ideas for sit-stand mechanisms are somewhat narrowed down, but until we decide on one speculation won't stop
Idea for motor was made somewhat obsolete after presentation research, but most recent meeting brought it back.
CAD will begin this week alongside more concrete ideation (FBD, FMEA)
Ordering parts for next iteration of frame & design will happen on Monday, fabrication will occur throughout the week
Model will be perforated tubing for a retractable frame design
Other main change will be inclusion of front swivel wheels for device support
Accomplishments from Previous Week
Research was done on different sit-stand mechanisms for viability
Over a half dozen viable mechanism ideas were generated
More detailed analysis and Pugh chart comparisons must be made
Motor and cylinder ideas were made mostly obsolete, but most recent meeting with Dr. Yu re-introduced them.
Design decision made to try out perforated tubing and front swivel wheels.
Experiment introduced to shave front extrusion bars for harness guide.
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Order parts for newer model (perforated tubing & front swivel wheels) (Sherman)
Fabricate new model (Ming Ming/Team)
Modify old model (extrusion frame)
Replace corner brackets with sturdier supports (Aryan)
shave down half of extrusion along front to allow harness guide to slide over it. (Elias)
Solidify decision on sit-stand mechanism, including CAD (Team)
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Start doing more detailed analysis, ordering, fabrication, justification and testing (already done with week 2, time flies).
Take another look at motor viability.
Main issues with existing sit-stand mechanism (rear brake from previous year cart) are lack of space and excessive effort required
If our design can address these concerns with the same model, we don't have to re-design anything.
Although appreciated, solutions do not have to be driven largely on physiological concerns, as long as they are safe.
Willing to go over budget for certain components, if there is a need for it with relevant analyses.
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Constant force springs won't work, previous year's team did analysis to prove this (in-person, 1/17 presentation comments)
Previous year's team have lots of analysis and justification for the spring choice in their design, take a look at it (in-person, 1/17 presentation comments)
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
4-wheel model will add an extra layer of difficulty in the sit-stand problem if we want our whole frame to fold (in-person, 1/17 presentation comments)
Risks and Areas of Concern
Motor can be very expensive and hard to work with, we would rather not work with one, but unless we provide sufficient justification to Dr. Yu for us to not work with motor, it is still on the table for analysis.
Our new model (perforated tubing & 2 front swivel wheels) needs to be analysed for weaknesses for us to be able to iterate again.
Resources or Information Required but not Available
Would like some professional advice & experience on motors and their viability in this application.
Schedule
Next milestone: CAD and ideate for mechanisms in order to make a more concrete decision
Gantt chart: part ordering, fabrication and testing will be done through our next meeting with Dr. Yu (1/27)
Budget (list amount spent and amount remaining)
4x 8020 extrusion bars--$41.39
Loop Clamps--$12.00
corner brackets--$29.05
Home Depot trip for screws--$4.94
upcoming purchases: perforated tubing and components for front 2 swivel wheels (wheels, fasteners, rods . . .)
Amount Remaining: $2512.62 (out of $2600)
Progress on Report and Webpage
Week 2 requirements for report have been completed