156B Week 7

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

• • Wedding cake internal metal structure components fabricated

    • Waiting to thread rods and fully assemble

  • MATLAB dynamic model of dive depth vs time, incorporating system compression, buoyant force, drag, weight, thrust being fine tuned

  • Battery drainage analysis is done and aiding in quantifying potential duty cycles for thrusters and linear actuator

Accomplishments from Previous Week

• • Created dynamic MATLAB model of system to aid in controller design

  • Demonstrated successfully ability to run linear actuator using Arduino PWM code

  • Battery life versus thruster and linear actuator usage analysis completed

  • Fabricated wedding cake components, waiting to assemble

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

• • Finalize design for linear actuator mount and fabricate (Zach)

  • Layout exact locations of sensors, piston, bulkhead connector, ballast, and any other components in end cap

    • Implement in CAD model (Doris)

    • Machine through holes in end caps (Duncan)

  • Interface pressure sensor to read in data and implement simple controller for thruster/actuator based on pressure error (Hugo/Michael)

  • Design PID controller for piston buoyancy control (Hugo/Michael)

  • Cut acrylic housing to length for precise fit with wedding cake

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

• • Suggested methods for implementing thrusters and updating dynamic model (5/16, in person)

  • Discussed PID control for piston buoyancy and suggested 10 Hz sampling of pressure data for averaging (5/16, 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)

• • Analysis on center of mass, pressure, and buoyancy (5/10, in person)

    • Center of mass found in Solidworks

    • Center of pressure is in the middle of the body because system is roughly symmetrical (not sure how to find in Solidworks, use Torque goal?)

  • Add more analysis to report (5/10, in person)

    • In the middle of correcting and updating report

  • Suggested having piston react an order of magnitude slower than thrusters (5/10, in person)

    • Noted for code and piston adjustment delay time

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 of buoyancy/center of mass/center of pressure locations

    • Potential moment on system during either descent, rise, or even both

Resources or Information Required but not Available

• • N/A

Schedule

• • Plan to have system constructed by early next week (5/22)

  • Updated Gantt chart.

Budget (list amount spent and amount remaining)

• • Spent: $1750.31

  • Remaining: $249.69

Progress on Report and Webpage

• • Website up-to-date

  • Received feedback on first draft of report

    • Correcting easy-fix issues such as units, wording, tense

    • Adding annotated figures throughout

    • Expanding on all areas of report and preparing for second draft