Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Analysis: Done
Design: Done
Fabrication: Almost done, finishing optical sensor mounts and control boxes by end of week
Tests: Done
Fiber Optics: communication confirmed, moving stepper motor appropriately, now just finishing up the PCB for limit switches
GUI: almost done, need to finalize limit switch functionality
Accomplishments from Previous Week
working fiber optics
confirmed sponsor's desired GUI functions
tested system in MRI room and determined accuracy and noise
Goals for Next Week (list names after each item). Use specific and measurable objectives.
finish gui, pcb, control boxes and sensor mounts, report, poster, website and presentation to sponsor
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
landmarking position - laser marker would be a nice 'bells and whistle' but not critical
process for landmarking is good
option to check sample manually
disable switch inside MRI room
controls inside of MRI room for future design
will try to include recommended implementation
shielding electronics
sponsor has copper tape and paint available for use if necessary
accommodating for backlash within the LabVIEW
recommended by sponsor: saving previous value in text file and read for use to determine direction of the movement
we are currently looking into it
Expert Mode -> disable or gray out developer functions, do not need to make invisible
instruction manual
describe GUI at both user and developer level
include comments in block diagram
maintenance
tensioning belt
dealing with backlash; how to test for backlash
troubleshooting
safety chapter - how to bolt down the motor (for future iterations)
shielded cover to avoid pinch points
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Presentation Comments by Delson
specify if sample mass 2 kg includes SF of 3 or need to add SF of 3
if wires are okay inside scanner room, why not use copper wires instead of fiber optics to the control room
copper wires can possibly act as an antenna and bring noise from inside the control room and distort the image
zoom in to design overview picture to fill full screen
put results and requirements exactly side-by-side
combine all numbers into a single accuracy and repeatability number and compare that to the requirement
show linear slider components picture earlier
how much resistance if stepper is removed?
3 N without the stepper motor
GeckoDrive does not provide current sensing?
no, the G201X stepper motor driver we are using does not have an output that tells us how much current is being used by the motor
G201X has a current limiting function, which reduces the amount of torque in the motor
did you search ways to find out if a stepper misses steps? since stepper is moving at a low speed, the back EMF never gets large enough when missing steps
"stall" torque test - show results on a motor torque-speed curve
was included on the next page
has the belt-clamp arrived?
apparently it was not shipped, JV said she would confirm with us today but we have a functioning belt clamp (make-shift) that can be used until that arrives
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
Presentation comments (5/29, in person)
add more labels for each component in the figures
can the metal components of your device be pulled into the MRI scanner?
highly magnetic components such as the motor and motor driver are bolted to the table to prevent them from being pulled into the MRI
they are also set the furthest away from the MRI bore, where the magnetic field is much less (around 5 gauss)
will the developer portion of the LabVIEW be removed for production?
for potential mass production, the developer portion will most likely be removed
however, the developer portion will be included in the deliverable presented to the sponsor to allow for further testing and improvements
try using a tensioner on your belt; designs for tensioning mountain bike chains
how are you planning on incorporating the laser crosshairs into the design?
the laser will be mounted either stationary on the platform or on a hinge
G723-400-4 NEMA 23 has a holding torque up to 400 oz-in, which is ~2.82 Nm; where did you get 0.19 Nm?
0.19 Nm was the value we calculated our system to need in order to operate, which is indeed much less than the motor capabilities
for current sensing, you could look into a sense resistor to be able to measure low currents
is there a backlash requirement? how to improve?
there is no specific backlash requirement; however the movement of the carriage must be within a tolerance of 0.5mm
the backlash will hopefully be improved with the use of an actual clamp plate
Report comments (Team #2)
maybe include a table and list priority levels of each deliverable
show overall design before describing functionality
there is a way to get rid of "double dimensions"
we prefer to have double dimensions for easier machining
could add a price range for bill of materials
include short objective of analysis
maybe reference equations used in analysis in the equation portion of appendix
try to make fiber optic send/receive circuit darker on report
label main sections of the PCB circuits
Website comments (Team #2)
make functional requirements and deliverables into a table and show priority of requirements
label images
show overall description of total design first
Risks and Areas of Concern
Belt clamp was not shipped, JV is supposed to confirm if it is shipping out today
Resources or Information Required but not Available
Schedule
Complete project
Update Gantt chart.
Budget (list amount spent and amount remaining)
$876.23 spent, $623.77 out of $1500 remaining
Progress on Report and Webpage
Report: working on appendix
Webpage: making final changes this week