156A Week 10

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

• • Ideas of mounting sensors onto SLK head were presented to Ernest

    • Sensors explored included pneumatic cylinders, FlexiForce sensors, springs, and load cells

    • See attaches files to find our presentations to our sponsor (Ernest), given on 3/9/20

  • FlexiForce sensor mounted to head of SLK seemed like the best choice.

Accomplishments from Previous Week

• • Further clarification of mechanism of machine

  • Researched each design proposal gone over by Ernest in the previous meeting

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

• • Work on risk reduction presentation to Prof Delson on 3/12/20

  • After that, work on actual risk reduction that we will present to Prof Delson on 3/17/20

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

• • (Wed 3/4/20) Present ideas with cost analysis, pros vs cons

  • (Mon 3/9/20) Presented ideas of mounting sensors onto head of SLK, single load cell with plate in tray, array of springs, and FlexiForce sensors

    • Springs most likely would not work, as they are not reliable and deflection of the plate would cause inaccurate readings

    • Mounting sensors onto the head of the SLK seems like the desirable choice, however we would need to find a way to attach onto each SLK head variant, possibly through multiple models that would fix to multiple variants of SLK heads

    • Single load cell with a plate above it may also work, however we need to find a way to minimize the moment created at the load cell from a force off-center of the plate.

      • Would also need a "spacer" to attach to the SLK head in order to measure the force of one particular head. The spacer would be attached to the SLK head and the load cell with the plate attached would need to be brought down the same distance as the spacer to avoid damaging any equipment

    • FlexiForce sensors are extremely cheap, great for risk reductions, and seem to be the desirable choice.

      • Accuracy is a large issue, however. Spec sheet says they are accurate for <+/-3%. With a load of 500 lbs, the error could be +/- 15 lbs, which is unacceptable

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

• • N/A

    • Didn't meet with Prof Delson week 9

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

• • Accuracy of FlexiForce design solution will be a problem

    • Need to find a way to increase achievable accuracy of these sensors

      • Either finding more expensive, more accurate sensors, or increasing the sensitivity in the circuit by choosing the proper resistors, capacitors, and op-amps

  • How to constrain the design solution to only move in the z-axis, without over constraining or impeding the system in any way

Resources or Information Required but not Available

• • If precision springs are actually attainable?

    • They've eluded Damon, Richard, and even our sponsor, Ernest

Schedule

• • Risk Reduction plan for next week

  • Update Gantt chart to reflect the proper risk reduction design we are going forward with

Budget (list amount spent and amount remaining)

• • N/A

Progress on Report and Webpage

• • 3/9/20

    • Update 156A Weeks 9 and 10, as well as Gantt Chart tabs to reflect the work we've done so far

  • 3/10/20

    • Further refine these tabs to update and improve our site 

    • Add a front page that attracts viewers