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Team 14026 – MSD I Presentation. Mike Allocco, Soham Chakraborty, Leslie Havens, Danielle Koch, Andrew Miller, Kristeen Yee, Stephanie Zambito. Agenda. Sensor Placement Pressure Sensors Flow Sensors Bill of Materials Budget Test Plan Risk Assessment Plan for MSD II. Problem Statement
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Team 14026 – MSD I Presentation Mike Allocco, Soham Chakraborty, Leslie Havens, Danielle Koch, Andrew Miller, Kristeen Yee, Stephanie Zambito P14026_Detailed Design Review 12/05/13
Agenda • Sensor Placement • Pressure Sensors • Flow Sensors • Bill of Materials • Budget • Test Plan • Risk Assessment • Plan for MSD II • Problem Statement • Engineering Needs and Requirements • Functional Decomposition • Week 6 System Design • Current System Design • Connection to PEV • Assist & CPR Mode • Tubing • Trachea • Lung P14026_Detailed Design Review 12/05/13
Problem Statement • Current State • 1st generation of a validation system • Desired State • Simulate the respiratory system and measure flow, pressure, volume, and oxygen concentration • Project Goals/Opportunities • Collect data to evaluate 13027’s PEV • Constraints • ANSI Z79.7 • ISO 5469:1967 • ASTM F1100-90 • ISO 80601-2-12 P14026_Detailed Design Review 12/05/13
Matrix P14026_Detailed Design Review 12/05/13
Functional Decomposition P14026_Detailed Design Review 12/05/13
Design Proposed Week 9 P14026_Detailed Design Review 12/05/13
Why the Design Changed • Testing the LTV • Connection to the MediResp-III • Breathing into the LTV P14026_Detailed Design Review 12/05/13
Why the Design Changed • Breaths per Minute • Breaths per Minute at 0.9 Lpb P14026_Detailed Design Review 12/05/13
WHY The Design Changed • The LTV takes readings at the beginning and end of the tubing • Using the LTV would require the team to reverse engineer the LTV • Would be outside the time constraint of the project • Potentially, would be outside the budget constraint of the project P14026_Detailed Design Review 12/05/13
Current System Design P14026_Detailed Design Review 12/05/13
Connection to PEV P14026_Detailed Design Review 12/05/13
Current System Design P14026_Detailed Design Review 12/05/13
Assist Mode Components • Actuation is anexcellent way to makea process repeatable. • The rotational energyof a small motor wouldhave to be converted tolinear pushing/pulling. • An easy-to-execute choicewas to use the rack-and-pinion • A lead screw was alsoconsidered, but these areless efficient P14026_Detailed Design Review 12/05/13
Assist Mode Components • The syringe is 150mL and we expect to move roughly 100mL at a time, based on a typical inhalation. • The rack part of the rack-and-pinion must make a solid connection with the plunger 100 mL Dist = x P14026_Detailed Design Review 12/05/13
Assist Mode Components • The rack will need support to avoid slipping out of place. • The typical solution is to fit the rack into a short channel to constrain its path. Characteristics of the Rack as Designed: Keep rack on a level with the pinion. Leave space (0.01 in) on either side. Fairly wide to allow for easierconnection to plunger of the syringe. P14026_Detailed Design Review 12/05/13
Assist Mode Components • THREE CARDINAL RULES OF GEAR DESIGN: • Meshing gears must have the same height, • Distance between gears’ teeth (“pitch”) should be as close to same as possible • Different number of teeth is mechanically advantageous for torque-to-turn ratio and for speed of rotation. P14026_Detailed Design Review 12/05/13
Assist Mode Components -35-45 HR -Pressure Angle 20deg -Circular Pitch 2mm -300mm Long -Pressure Angle 20deg -Circular Pitch 2mm -Bore Size to Order -23 Teeth RM-2M-300 SH2MS2B250F7A P14026_Detailed Design Review 12/05/13
Assist Mode Components • The gear connection to the stepper motor relies on the motors default pin being able to find purchase in the gear bore. • The round pin of the motor is 5mm. We expect to order the gear at a NEMA#23 single-flat bore type. P14026_Detailed Design Review 12/05/13
Assist Mode Components • SIZING OF THE STEPPER MOTOR • The maximum expected resistance to motion is a volume of 100mL of air. • We would like to be able to apply the pressure of roughly half a breath (17 cmH2O or 1.667 kPa) • We would like a fairly quick reaction time of 0.2 sec. • Recall that Work/Time is Power, so analysis yielded: • Moreover, stepper motors are roughly 50% efficient, so the stepper motor selected was sized at 2 Watts of power. • The stepper motor is also bidirectional to allow for retraction. P14026_Detailed Design Review 12/05/13
CPR Mode • Originally, the team planned on using the syringe, stepper motor, and actuation to simulate a patient receiving compressions • At first team 13027 counted compressions by sensing pressure • Team 13027 has narrowed the scope of their project P14026_Detailed Design Review 12/05/13
Current System Design P14026_Detailed Design Review 12/05/13
Tubing • Why PVC? • PVC has many standard sizes and variations for connections. • Will be easier to implement. • PVC has smooth Inner Diameter walls. • Turbulent Vs. Laminar Flow? • If Re<2300 then we can assume flow is laminar: • , for air at STP: , and • Where , , • 20.83<<2300 therefore we can easily assume flow is laminar. P14026_Detailed Design Review 12/05/13
Current System Design P14026_Detailed Design Review 12/05/13
Trachea Resistance • Airway Resistance Basics • (1) • Orifice Plate Feasibility • (2) • plugging in ρQ=ṁand solving for results in, • where ΔP comes from Equation (1)(3) • Which results in orifice plate diameters as follows: • These orifice plate ΔPs will need to be validated; diameters may need to be adjusted based on empirical correction factors and experimental results. P14026_Detailed Design Review 12/05/13
Trachea Resistance cont’d. P14026_Detailed Design Review 12/05/13
Current System Design P14026_Detailed Design Review 12/05/13
Lung Compliance • How can we vary lung compliance with only one test lung? • Add a weight • Use a rubber band P14026_Detailed Design Review 12/05/13
Bezier Curves • Bezier Curves are splines that are controlled through the manipulation of control points P14026_Detailed Design Review 12/05/13
Bezier animation P14026_Detailed Design Review 12/05/13
Compliance program • Uses Bezier curves to model an ideal breath curve and generate simulated data based on this curve • We “force” the program to generate a curve that we want and use it to predict how different factors will affect our results • 5th degree Bezier Curve gives more control • This equation gives an x or y value for a specific t value. 0≤t≤1 • Rearranging the equation allows us to get control points from given coordinates. • Gives us a useful estimation of data P14026_Detailed Design Review 12/05/13
Comparison to Real data P14026_Detailed Design Review 12/05/13
Current System Design P14026_Detailed Design Review 12/05/13
Sensor Placement P14026_Detailed Design Review 12/05/13
Pressure Reading • SM5470 -Product of Silicon Microstructures Incorporated • Low Pressure Scale 0-3 PSI • Gauge Pressure Sensor • Accuracy is .25% • Used within Medical Instrumentation and Monitoring P14026_Detailed Design Review 12/05/13
Sensor Placement P14026_Detailed Design Review 12/05/13
Flow Meter • TSI 4000 Series Flow Meter • Flow Measurement: • Accuracy +/- 2% of reading • Range 0.01-99.9L • Response: 4ms • Pressure Measurement: • Accuracy +/- 1 kPa • Range 50-199kPa • Computer Cable (mini-DIN to 9 pin D-Sub) allows interface between device and computer. • Outcome: Data logging for flow and volume measurements *Note – same device used by 13027 to calibrate MediResp-IV P14026_Detailed Design Review 12/05/13
Preliminary Flow testing • Tested Mike exhalation of breath • Connected tubing to flow meter • Read in real time data P14026_Detailed Design Review 12/05/13
Sensor Placement P14026_Detailed Design Review 12/05/13
Release Valve • 4320T15 Miniature PVDF Relief Valve • Temp. Range: 26F to 255F • Use with air • Relieve excess pressure in air lines • Valve body is PVDF • Seal is Buna-N P14026_Detailed Design Review 12/05/13
Current System Design P14026_Detailed Design Review 12/05/13
Electrical Schematic P14026_Detailed Design Review 12/05/13
EMANT300 Low Cost USB 24 DAQ Module • Up to 6 channels of differential multiplexed ADC • Single channel 22 bit @ 10 samples/sec • Single channel 16 bit waveform @ 2500 samples/sec • 1 channel of 8-bit D/A conversion • 8 digital IO channels • One 16-bit general-purpose counter or 16-bit PWM • USBconnection • 25 pin D-Sub connects to physical world • Application adaptors with instructional guides • LabView compatible • Cost = $99.00 http://www.emant.com/251004.page P14026_Detailed Design Review 12/05/13
PCB Layout P14026_Detailed Design Review 12/05/13
Bill of Materials P14026_Detailed Design Review 12/05/13
Budget P14026_Detailed Design Review 12/05/13
Test Plan for our system • Leak Test • Test sequentially over build of assembly using flow meter • If lose 1% of flow, then look into forming better seals • Calibration Test of Pressure Sensors • Use manometer to validate pressure sensors • If within 5% of the sensor, then proceed • Calibration Test of Flow Meter • Use validated pressure sensors over a known distance to validate flow meter • Take into account the discrepancy between analytical and experimental values • Timing of Actuation • Use stopwatch or switch to time and validate actuation is working as expected • See mitigation plan (in future slide) P14026_Detailed Design Review 12/05/13
Risk assessment P14026_Detailed Design Review 12/05/13
Risk Assessment P14026_Detailed Design Review 12/05/13
Risk Assessment P14026_Detailed Design Review 12/05/13
Plan for Msd II P14026_Detailed Design Review 12/05/13