156B Week 10

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

• • Micro-scale prototype design is frozen

  • Full electronic control of motor with PWM ramp-up, spool indexing, and actuation under load verified

  • Machining ongoing for current and final micro-scale prototype version.

Accomplishments from Previous Week

• • Key external test milestones completed (William)

    • Force test

    • Distance test

  • CAD and last prototype iteration finalized/frozen (Andrew)

  • Hand-held controller design finalized (Wesley)

  • Machining on final prototype iteration started (Kevin)

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

• • Implantation test in dead rabbit cadaver (Thurs 3/14) (Andrew, William, Kevin, Wesley)

  • Finish machining and assembly of last prototype iteration (Kevin, Andrew)

  • Finish 3D printing and assembly of hand-held controller (Kevin, Wesley)

  • Finalize CAD of scaled-up actuator for poster session (Andrew)

  • Finish 2D drawings IAW ASMEY14.5/GD&T for applicable parts (Andrew, Kevin)

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

• • Current prototype as of now fulfills expectations, just needs to demonstrate implanted nerve pulling for completeness (in person, 3/6)

    • Team acknowledged - focused on making the current prototype work inside the cadaver, the "final iteration" will not make it into implantation before finals week, but will be machined, assembled, and verified to work externally.

  • Suggested set screw holding of backbone rather than welding it to the actuator enclosure. Also recommended increasing backbone OD to 4mm in order to avoid excessive bending moment issues due to rabbit movement. (in person, 3/6)

    • Design suggestions were implemented. Resulting final enclosure design is still within sponsor bounding box, and machinable. Extrusion with counterbore and set screw holes was added to side of enclosure to accommodate the design suggestion.

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

• • Last progress report was half empty (in person, 3/7)

    • Team acknowledged error - forgot to save an update that completed the progress report

• Can do a preliminary submission of final report before Friday due date for peer review by MAE156B instructors (in person, 37)

  • Preliminary version was submitted on 3/10.

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

Risks and Areas of Concern

• • Amount of time left to get everything done

    • Short turnaround between rabbit cadaver implantation test and report due date (Fri) - will need to work quickly to process data and format neatly in report

    • Still need to scale up the design for visual purposes/poster session

  • Motor internal gearbox strip

    • Running motor at full voltage and PWM results in planetary gearbox stripping at stall conditions, plastic gears not as robust as expected

    • Does not occur at lower voltages

      • Still need to fine tune algorithm to be able to detect stall conditions at lower voltages - consider swapping load resistor on current measurement board for higher resolution

Resources or Information Required but not Available

Schedule

• • Describe upcoming milestone

  • Update Gantt chart.

Budget (list amount spent and amount remaining)

• • Amount spent: $333.27

  • Amount remaining: $1166.73

Progress on Report and Webpage