156B Week 5
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Printed and assembled valve design
Tested under normal conditions (not in device under pressure)
Developed code to control servo position by potentiometer
Accomplishments from Previous Week
Printed and assembled single valve for testing
Code can successfully control a single servo
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Test valve and record data with RR device (Josh)
Update code to incorporate 3 servos, 3 potentiometers, and LCD screen readout (Jeffrey)
Continue working on report (Obed, Basil)
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
All comments via Zoom on 4/29
Recommends measuring pressure drop across channels in series to ensure they are the same
Recommends we label the plots so they may stand alone without the need to explain
Make it clear we are using water in our device but cells need DEMEM medium to survive which is water with electrolytes
Okay to assume it behaves like water because the viscosity is constant
Soft tube introduces compliance
Recommends using as little of the soft tube as possible to avoid compliance due to expansion/contraction due to pulsatile flow
We will need to order additional rigid tubing
Breadboard is okay for developing our prototype
Wants to see a detailed budget
Preferably include pictures and the cost associated with that item
Valves
Needle valves
Electronically controlled is too expensive
Affects flowrate too much to be viable option, introduces very high resistance to the system
Crop the bar plots, only tops of data are of interest
Did this for Proof of Concept presentation
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
All comments via Zoom on 4/24
Data is much more organized and clear
Absolute pressure plots allow us to more clearly see what's going on and determine if it makes sense
Suggests taking pics of parts being 3D printed
Added pics to presentation
Suggests finding the weight needed to obtain certain deformations in and forces involved by FBD to obtain a Factor of Safety
Should aim for a minimum of 1.5
Concerned about noise in steady state data
Plan to use capacitors to filter noise as per manufacturer recommendation
Wants whole class to understand in reference to fluid mechanics
Included extended bernoulli analysis of tube diameter and effects on pressure in Proof of Concept presentation
Suggests adding lubrication to cam surface to reduce friction wherever possible since linear sliders are susceptible to jamming
Friction could cause hysteresis
Recommends controlling servo is top priority
Should quantify performance of the valve somehow
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
none
Risks and Areas of Concern
Attaching valve to the device securely
Resources or Information Required but not Available
none
Schedule
Implementing one servo valve into the device
Integrating servo valve, pressure sensors, and LCD readout
Budget (list amount spent and amount remaining)
~$300 spent, ~$2-300 remaining
Progress on Report and Webpage
Working on 1st draft
Updated internal page
Added Proof of Concept presentation to media section