156B Week 3

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• Three design concepts have been decided upon. Testing will begin once parts arrive in the mail.

• The standard lubrication interval is after 5 million revolutions. Calculations will be made to determine the amount of time it takes for the ball screw to make those revolutions.

Accomplishments from Previous Week

• Three configurations have been chosen.

• Parts are approved to be ordered by sponsor, but need Professor approval

• MATLAB Simulations further investigated

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• Receive parts and begin our testing phase.

• Design several tests for the prototype once the parts have arrived.

• Begin machining parts necessary for testing.

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• Jules advised against using the compressed air design since it would be difficult maintaining a consistent buoyancy. The compressed air design has been ruled out. (4/12/13, in person)

• A suggestion was made to try all three of our proposed configurations and see which one works best. The components were ordered this week. (4/12/13, in person)

• Jules is concerned about how often the ball screw would need lubrication. These questions are being addressed to the manufacturer of the ball screw. (4/12/13, in person)

• Jules was interested in the change to the operational life of the unit caused by the removal of one of the batteries/new motors. Model planned on similar estimates used in initial design but with new parameters. (4/12/13, in person)

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Looking into the buoyancy effects at depth, we reviewed the methods we plan to use for buoyancy control and created some MATLAB simulations with the current set up

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• All comments from students on 4/10 during design proposal presentation:

  • could change piston diameter 

  • what is current noise level? measure with microphone & o-scope to manipulate noise

  • possibly look into filters for collecting hydrophone data

  • add pros & cons to design proposal table

  • for testing: attach rope to pull AUE back up

  • suggestion for rack& pinion to push piston....?

  • nylon gears are good --> less friction

  • use analysis to decide on design instead of buying stuff and seeing how it works

  • look into using external bladder with either oil or air

  • for simulating water depth: access to pressure tanks @ scripps?

  • different material balls in ball screw to reduce noise?

Risks and Areas of Concern

• Area of concern: how often ball screw would need to be lubricated--is this too high maintenance?

Resources or Information Required but not Available

• • N/A

Schedule

• Milestone for next week: receive parts for testing. Design/brainstorm motor mounts.

• Gantt chart is updated.

Budget (list amount spent and amount remaining)

• Parts haven't been ordered yet, so no budget money has been spent

Progress on Report and Webpage

• The Impact on Society section for the final report is to be completed.

• The site has been updated with sponsor comments.