156B Week 7

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

• • Analysis:

    • Conducted analysis of web tension values needed to send to company in regards to purchasing a cartridge style transducer. 

      • Result: They do have something that would work within our requirements, and we are in contact with them currently. 

    • Control Algorithm:

      • Met with Ed to discuss best controls approach to the system and this is discussed further below.

  • Design:

    • Currently working on finalizing the designs of the following subsystems:

      • Tension monitoring system

        • 90 degree angle idler pulleys

        • Tension transducer mounts

        • Pulley mounts

        • Additional design to back up plan for tension transducer using load cells. 

  • Fabrication

    • Currently fabricating the following parts:

      • Take up spool:

        • A new take-up spool is being manufactured that has its axis horizontal, has a removable cap, and has a fitting lock. 

      • Spooling Guide:

        • Making a new spooling guide that will be attached to a servo that was ordered.

  • Tests

    • Length Tracking:

      • Conducted length tracking at the feeder mechanism assuming no slip. 

      • With correction factor, were able to find consistent length spooled within 2 % error. 

        • This is outlined further in accomplishments from previous week below. 

    • Mechanical Damage:

      • Conducted tests where tubing thickness was tested before and after being fed through the feeder mechanism. 

      • Main Result:

        • Compression was minimal and within satisfactory limits for sponsor.

        • This is outlined further in accomplishments from previous week below. 

    • Tension from Feeder Mechanism

      • Conducted test to determine tension force applied to tubing from the feeder mechanism using a load cell. 

      • Main Result:

        • Tension was in line with expected value. This value will be used to further test mechanical damage to the material. 

Accomplishments from Previous Week

• Controls algorithm:

  • • Met with Ed to discuss controls algorithm and decided a PD controller used in conjunction with the tension transducer would be sufficient.

      • Control would be implemented at the take-up spool around a nominal target velocity.

• Length Tracking Test:

  • • Conducted length tracking for various amounts of time to see if length tracking was consistent at feeder mechanism. 

    • Results:  

• • • Main Result:

      • Tracking length seems to be consistent with 10% extra length be calculated using the encoders. This may be due to strain developed in tension zone 1.

      • With accounting for this extra 10%, the extrapolated error is within the 5ft error functional requirement.

      • We are going to try working with slower speeds with a new high torque motor which should give us better results as well. 

• Mechanical Damage Test:

  • • Tested three pieces of tubing fed through the feeder mechanism and our sponsor measured the double-wall thickness before and after the feeder mechanism.

    • The results were:

• • • The average results were:

• • • Sponsor comments:

      • There is a difference before and after, but the final thickness still meets requirement even though this is damaged spool. 

    • Outcome:

      • Feeder mechanism does not compress the tubing enough to make it not functional. Design is moved forward. 

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

• • Finish design and fabrication of the following parts:

    • Take-up spool: (Iman)

    • Mounting and Pulleys for tensioning system (Jhon)

    • Mounting for take-up spool (Iman)

    • Mounting for supply spool (Jhon)

  • Finalize tension monitoring device:

    • Finish discussing options and pricing with Cleveland Motion Controls on their available transducers (Patrick/Anthony)

    • Develop backup tension monitoring design with load cells or strain gauge (Patrick/Anthony)

  • Testing:

    • Install and test new high torque motor on feeder mechanism.

    • Install spooling guide and test functionality.

    • Test failure during air pressure test using PSI specification supplied by sponsor. 

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

• • Sponsor came to the campus to view the prototype developed for the proof of concept. 

  • Comments from followup after meeting:

    • Cannot use acrylic since it builds up static charge.

    • Feeder mechanism compressed the tubing slightly but was within functional requirements of the desired outcome. 

    • Should use dry bearings and no lubricants to adhere to cleanroom guidelines as indicated by Mr. Gillett. 

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

• • Presenation for proof of concept was held last week in place of a meeting. 

  • Notes/Comments from POC presentation:

    • Analytical slides should have major outcome of test, and focus less on explaining the details of the analysis. 

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

• • N/A

  • Will update after we get comments from the students on the feedback form. 

Risks and Areas of Concern

• • Risk Areas:

    • Feeder Mechanism:

      • Still finalizing tests with regards to failure of the tubing passing through the feeder mechanism.

      • Will conduct air pressure test this week for final verification.

      • Will conduct tensile strain relaxation test for additional verification.

    • Tension monitoring

      • Need to finalize the design and whether or not we are purchasing this or making it ourselves. 

      • Need to implement into control system

    • Control and Tension on Take-up spool

      • Since final prototype is not developed yet, we cannot yet test take-up spool tension.

      • We need to finalize and develop the prototype by next week to conduct control tests on the system. 

Resources or Information Required but not Available

• • N/A

Schedule

• • Gannt chart updated. See Gannt chart link.

  • Schedule is outline in proof of concept presentation and is as follows:

Budget (list amount spent and amount remaining)

Progress on Report and Webpage

• • No progress has been made since the submission of the 50% on Friday of Week 5.

  • Will revisit this week to update and make significant progress.