Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Nearly all major systems of the final design have undergone preliminary design, prototype, and/or component tests.
The electrical DPDT switch circuit was connected to two actuators in parallel. The component testing validated the final circuit design.
The appropriate length actuators (4") arrived Monday night after an unexpected delay from Friday which prevented mounting and force testing.
The hinge lock system has been designed and a prototype is being 3D printed in conjunction with machined struts and mounts.
Experienced process errors in printing on Friday that prevented component testing.
This week is focused on:
Iterating, improving, and refining the wheelchair design and system components based on testing findings.
Assembling the parts altogether.
Must consider mounting and component adjustment to prevent interference.
Performance testing, if time permits.
Key insight from sponsor meeting is to re-prioritize the consideration of comfort components, and how they integrate, into the final design.
Accomplishments from Previous Week
Received linear actuators with 10cm (4") stroke for sit-stand mechanism
Delivery was unexpectedly delayed from Friday to Monday.
Built and tested circuit diagram for wiring 2 actuators in parallel to the same DPDT switch.
Modeled and began printing/fabrication of harness locking component of sit-stand mechanism (3D printed locks, machined struts).
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Mechatronics component testing: Actuator lifting system
Purchase appropriate battery and new ON-ON switch/button to power sit-stand mechanism (Ming Ming)
Design, assemble, and mount actuator system (Ming Ming)
Test the lifting force of actuators is sufficient for sit-stand purposes (Aryan)
Mechanical component testing: Hinge locking system
Finish fabricating and assembling harness locking component for testing (Elias & Sherman)
Design button interface/implementation (Aryan)
Complete and fully assemble hardware and electrical system. If time permits, begin first round of testing for final design.
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Consider larger wheels for both the front and back wheel struts (in person, 2/17)
Hinging lock system:
Make sure 3D printed harness coil stop won't break from usage (in person, 2/17)
Is it possible to match the amount of freedom the harness has (in length) to the distance the actuator has extended when in motion? (in person, 2/17)
Re-prioritize consideration of comfort:
Ways to easily incorporate loading of Bodie's diaper pads (in person, 2/17)
How to position saddle so it cradles Bodie comfortably in all (stand, sit, lay down) positions (in person, 2/17)
Clearance between inner and outer frame for components that need to go between them (diaper clips, harness coil uprights) (in person, 2/17)
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Consider spring support for inner frame in sit-stand mechanism (in person, 2/12)
Build and test critical sit-stand and lock components (in person, 2/12) Done
Start looking at button for Bodie, only 3 weeks left (in person, 2/12) Preliminary button and circuit testing has been completed
Report feedback (in person and through comments on copy of report, 2/12) In progress
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
N/A
Risks and Areas of Concern
Harness coil & stop:
Is 3D printed durable enough? - Bodie has broken retractable leashes
Lock system performance (doesn't catch, slips too easily from applied force, slips out from vibration . . .)
Bodie button usage (hasn't been looked into much yet, is a design assumption that Bodie will be able to use button with no problems)
Resources or Information Required but not Available
Calipers, rulers and mills in metric (is a joke)
How to improve lock catching mechanism for harness coil (angling the teeth, encasing entire contraption, . . .)
How to use 3D printers on 3rd floor without getting usage errors
What material & densities do the printers use (for FEA)
Schedule
Describe upcoming milestone
test new actuators, design mounting for them to connect and operate on inner & outer frames
3D print and test harness leash locking mechanism, might be iteration intensive to get one that works
start looking at button for Bodie & how to get him to use it
Update Gantt chart.
Budget (list amount spent and amount remaining)
(4) 8020 extrusion bars--$41.39
Loop Clamps--$12.00
Corner brackets--$29.05
Home Depot trip for screws--$4.94
Linear actuators & peripheral components (power supply, mounts): $310
Gate latch--$4.49
**4'' actuators (in process of returning 12" actuators):
Amount Remaining: $2210.62 (out of $2600)
Upcoming purchases: perforated tubing and components for front 2 swivel wheels (wheels, fasteners, rods . . .)
Progress on Report and Webpage
Report is 50% done as expected by the week 5 deadline
Webpage has content on front page, most of our working files are still on separate drive