156B Week 8

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

• • Closed loop control of 3dof stage accomplished

  • Schematics for machining draft completed

  • Ready to order bias springs

  • New flexures ordered and design requirements of resting shelf found

Accomplishments from Previous Week

• • PCB draft Schematics/layout made

  • CAD for deliverable made

  • decided on bias springs to use.

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

• • PCB order submitted (Kyle)

  • Implement target wire length code & hall sensor off-axis sensitivity correction into control code (Chad)

  • Schematics finalized, machining starter (Ben & Carl)

  • Build Arduino Shield with voltage divider on analog inputs (Edar)

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

• • Optimistic about project

  • Would like to see high flexure stiffness issue resolved with different flexures rather than thicker SMA wire

    • Resting Shelf Solution

      • In consideration but requires tight tolerances.

    • Multiple smaller flexures

      • Not feasible.  Max buckling force decreases slower than flexure stiffness with diameter so more smaller flexures will give greater stiffness for less buckling force.

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

• • Improved presentation

  • In CAD, could show importance of having pins line up correctly.

  • Pedro, 2/20: Look into ease of manufacturing prototype.  Excess material versus having separate parts

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

• • None this week. 

Risks and Areas of Concern

• • Misreading in linear encoders when mechanism translates in x- and y-directions simultaneously or rotates.

  • High tolerances required for resting shelf.  Possible friction in the design

Resources or Information Required but not Available

• • None at this point.

Schedule

• • 2nd draft of report (Thursday)

  • Website updated per comments (Thursday)

  • Show PCB & Machining schematics to sponsors for comments (Tuesday)

  • Update per comments (Wednesday)

  • Design Proposal Presentation (Saturday Night) 

Budget (list amount spent and amount remaining)

• • Amount spent: $269.42, Amount remaining: $2,230.58

Progress on Report and Webpage

• • Small updates on website