156B Week 2
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Further literature review is in progress
Failure analyses (listed on the week 1 page) have been started
Timeline of deliverables (see below) has been established
Accomplishments from Previous Week
CAD is now 90% complete (SEE ATTACHED FILES BELOW) --> may change depending on research
Established new scope of the project (see below)
Established new timeline of the project (see below in Schedule)
SCOPE/DELIVERABLES (Must Have/Nice to Have)
Robust model of system
Simulation of acceleration vector(s) under generic profile
Mechanical Design
CAD
Component selection
Component analysis
BOM/Budget for manufacturing
Electrical Design
Circuit diagram
Software Design
Drive software
UI
Controller design
Broader system analysis
See 156B Week 1 for analyses
Documentation package for next quarter’s students
Consider making their project mainly manufacturing/software design
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Have literature review complete and equations of motion established (ALL)
Research floor mounting & vibrational effects (ALL)
Equations of motion for centrifuge (Peter & Nicholas)
Optimal number of degrees of freedom
Inertia as a function of bucket tilt (David)
Dynamic simulation of the system in Simulink given the equations of motion determined (Nicholas)
Complete CAD with new bucket design if confirmed at next sponsor meeting (Peter)
Complete Design Proposal Presentation (Clara, Labiba, David)
Complete rough draft of report (Clara, Labiba, David)
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Images of current CAD were sent to SpaceTango and Arthur C. Clarke Center (4/6/20)
Concerned about bubbles interfering with the microfluidics if not managed/oriented properly (4/5/20)
Suggested a system with a swinging bucket design/more degrees of freedom in movement
Also concerned about vibrations interfering with other experiments in the building--> pending response from building manager (4/5/20)
Safety concerns --> see Risks and Areas of Concern (4/5/20)
Would like braking mechanism or other appropriate solution to make sure that high speeds are not maintained in the event of an E-stop
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
From instructor meeting (4/7/20):
Need to find literature/resource to confirm if design is appropriate
Suggested more robust FEA software such as NASTRAN
Need to find literature on machine design, specifically for the braking mechanism and motor shaft
Crucial deliverables:
Robust system model
Mechanical design of components
Component selection
BOM
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
Dynamic simulation of the system is most important; will use Simulink for modelling and controller design
Sudden stops to provide the discontinuities provided in target acceleration profile may cause stress on arm and motor shaft and decrease machine life
need to design for optimal performance life
need to test/model to make sure the equations of motion are correct
Safety concerns:
E-stop needs to be implemented (could use reverse motor control, decoupled motor control, braking system?)
Braking system with reverse motor control is current solution being researched
Needs to be up to same standards as CNC mill
Resources or Information Required but not Available
Need definitive textbook/resource on proper centrifuge design and equations of motion
Pending software license for NASTRAN/similar FEA software
Schedule
Update Gantt chart.
Complete research/literature review.
Assign analyses to team members.
Assign deliverables to team members.
GENERAL TIMELINE
Design ideation (what are possible solutions/configurations?) WEEKS 1/2
Research WEEKS 1/2
Dynamic simulation WEEKS 2/3
Set DOF
EOM
Controller design
Component selection
Friction calculation (i.e. drag)
Gx, Gy, Gz (M, V, A)
Graphs
Engineering analysis
Select components (motor, controller, software, brake?, shaft, bearings) WEEKS 3/4
Repeat simulation for final analysis (With more accurate system representation, change DOF, arm length) END OF WEEK 6
Final design (DOF, key geometry) END OF WEEK 6
Cost bracketing based on material selection, manufacturing methods, etc. WEEK 7
Roughed manufactured component design (ask about coding the interface) WEEK 8
Component analysis (Dynamic/static, modal, DFMEA, reliability) WEEKS 8/9
Allow for next group to pursue open questions if necessary
Thorough manufactured component design WEEKS 9/10
Final CAD model
Documentation
Electrical design? Circuit drawing
Basic code for interface
Budget (list amount spent and amount remaining)
N/A
Progress on Report and Webpage
Weekly progress reports
Report sections completed:
Background
Review of Existing Solutions
Statement of Requirements
Deliverables
Title page
Appendix with Individual Component Reports