156B Week 8
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Motor, shaft, bearings have been sourced
Sling material has been sourced
Bearing analysis complete, sling pin lug analysis complete
Waiting on quotes for brakes
Still need to decide on material for counterweight
Arm final CAD still in progress
Center stack final CAD still in progress
Accomplishments from Previous Week
Motor, shaft, bearings have been sourced
Sling material has been sourced
Bearing analysis complete, sling pin lug analysis complete
Waiting on quotes for brakes
Goals for Next Week (list names after each item). Use specific and measurable objectives.
For Week 9 (5/26/2020)
Finish CAD with all selected components
Finish analysis on individual components
Complete simulation with updated motor/inertia parameters
Complete BOM
For Week 10 (6/2/2020)
Complete FMEA
Finish drawings for machined components
Make CAD animation of system
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
5/19/20 meeting:
Would like a name for the machine (Erik)
Discussion on brake component:
braking is for safety and for acceleration curve
operation/testing after multiple uses → lots of testing uses (100s of runs, 1-10mins)
gearbox loading & brake loading will be very important for machine life → esp. with backdriving
operational life of machine: ~3-5 years
longest time in use: no hypergravity, replicating conventional launches, repeated runs up and down → should only be a few minutes each time
Might make more sense to just replace worn out back driven motors instead of buying $2000 brake
Twyman: described launch profile as consistent thrust in one direction, then zero gravity for a few seconds right before actual 1st stage (shock event), a little more zero gravity before 2nd stage, goes up to 3.5G
To decide on brake, we need a simulation with and without to see if brake is necessary to follow drops in profile
Current sim has only brake no backdrive → Nicholas plans to look into this situation
Erik: it’s a tradeoff problem, brake control + motor control or just replace motor, but replacing motor might make system unreliable if load is 100% on the motor
→ final decision, both sponsors okayed the brakes if necessary
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
5/19/20 meeting:
R = 0.995 at minimum for research equipment
Instructor recommended tapered roller bearings
→ also brought up concerns about underloading bearings
Launch load validation needed for the camera users
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
Center stack calculations need to be rechecked
Arm tangential forces during sudden stops and starts must be checked with FEA
Resources or Information Required but not Available
None
Schedule
Describe upcoming milestone
Update Gantt chart.
Budget (list amount spent and amount remaining)
N/A
Progress on Report and Webpage
Second draft of report to be completed by 5/24/2020
Webpage ~70% complete