156B Week 5

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

• • All sub-assemblies (carriage, rail system, crank mechanism) are ready to be mounted on the base plate, once the ideal configuration and precision of the crank mechanism has been determined/achieved

  • The sub-assemblies have been joined together by temporary means (i.e. double-sided tape) in order to evaluate how components work together.  Jamming was found associated with the linkages, and has been reduced by removing bearings out of 1 of the linkages.  This will require a revision of the crank-mechanism, which is currently under development.

  • Additional purchases have been made, incl. telephone wires, jacks, and hubs; power supply; rubber matt for the base plate, and new shaft

Accomplishments from Previous Week

• • The carriage has been successfully glued/assembled together

  • Rail system has been attached temporarily to the carriage system in order evaluate if jamming or high friction was a problem >> it works properly, as expected

  • Clips have been fitted & attached to carriage so that each monitor slides in & out the carriage easily, but has enough resistance to keep the monitors properly in place

  • All parts of the crank mechanism have been fabricated and can be rearranged according to needs (position of linkages can be changed, and the sprocket wheel can be  easily interchanged with a bevel gear, for instance) 

  • Orders were placed (4/24) and arrived (5/1) for a universal mounting hub for the 6mm motor shaft, which allows us to mount sprockets without set screws; and a "Protoscrewshield", which extends all pins of the Arduino out to 3.5 mm pitch screw terminals

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

• • Replace both short shafts on carriage subject to lever arm moments with one long shaft,which has been ordered (Shannon)

  • Cut out support brackets for this shaft on the Lasercamm (Roque)

  • Solder remaining electronics used for accelerometer and motor driver (Mark) 

  • Reassemble the crank mechanism with quarter inch shaft, which has been ordered (ALL); this includes:

    • re-manufacturing/machining of affected linkages (Chris)

    • determining the optimum configuration of the crank mechanism parts (i.e. the configuration by which the smoothest possible oscillatory motion can be achieved) (Shannon)

    • Cut out an additional acrylic sprocket with set-screw hubs (Roque)

    • Ream the holes of all these acrylic parts to achieve high precision when mounted (Mark)

  • For the bevel gear option: Manufacture a block of proper height, on which the motor with bracket can be mounted; the motor shaft must be the same height as the crank shaft (Chris)

  • Connect / solder the electrical components so the motor can be tested and accelerometer data can be taken (Shannon)

  • Configure the layout of the telephone cables and 5-way hubs (ALL)

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

• • We asked the sponsor via email how many wires per network cable are used, since there are variations.  Dr. Joiner replied that they use 4 wires (email, 4/30/12)

  • At our last meeting, we showed the sponsor our partially complete apparatus, along with the SolidWorks model.  With regards to the telephone cables used for the activity monitors, Dr. Joiner mentioned that they can be easily "daisy-chained" together without any particular restrictions in our case.

  • The sponsor confirmed that they are satisfied with our initial "1-monitor" prototype, which they are currently using

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

• • Progress report: Upon Dr. Tustaniwskyj's request, the accomplishments for the previous week, and the goals for next week have been covered in more detail (in person, 4/25/2012)

  • Yoshio Tsuruta and Dr. Tustaniwskyj urged us to implement velocity control in the software.  We are currently researching this topic (in person, 4/25/2012)

  • For components subject to high stress, Yoshio Tsuruta and Dr. Tustaniwskyj recommended the use of materials  less prone to cracking than acrylic, s.a. Delrin or anodized aluminum. >> The linkages have been manufactured using Delrin and the stress on the two shafts on the front end of the carriage will be replaced by a single shaft, with the addition of support brackets (in person, 4/25/2012)

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

• • One student wondered why we are using acrylic and aren't using "better" materials (in person, 4/22/2012)

  • Nearly every student we've encountered last week and was not aware of the specifics of our project didn't understand "why there isn't an easier way to wake up the flies" (in person, 4/21-4/25)

Risks and Areas of Concern

• • Jamming or high friction of the entire apparatus due to misalignment and/or imprecision, and the ability of the motor to fulfill its requirements as a result of this problem.

Resources or Information Required but not Available

• • none

Schedule

• • The next step is to resolve the problems associated with the crank mechanism (1st part of week 6),

  • then assemble all components on the base plate and test the apparatus with the motor (2nd part of week 6)

  • Finally, we will get started on the programming of the closed loop control (3rd part of week 6)

Budget (list amount spent and amount remaining)

• • amount spent:

  • amount remaining:

Progress on Report and Webpage

• • The report and webpage are about 75% complete at this point in time