Integrated System Build & Test with Customer Demo
Table of Contents
Review of Action Items
- Developed method for measuring compliance
- Created measurement method for the turn valve
- Built a drain location for ease of use
- Pressure trouble shooting to get outputs of 120/80
- Painting display box
The compliance tanks have been built and integrated into the system. The changes to the circulatory system include:
- The placement of the flowmeter: This is now attached directly to the pressurized tank to prevent vibration due to water-hammer.
- The method of adding resistance: The previous pinch valve was not robust enough to provide the desired outputs. An inline turn valve replaced the pinch valve and provides accurate outputs with a high sensitivity. The high sensitivity is good because the compliance changes can be done within one valve rotation.
- The types of fittings: The previously used fittings for the tanks to tubing and heart pump to tubing were no longer available. To keep consistency in color all connections were replaced.
- Added a way to drain the system
The previous measurement method was manually measuring the the height. The design was changed to a turn valve because the previous pinch valve was unable to cause the flow restrictions needed to control compliance.To make it simple for the students to measure compliance the following indicator was designed. The indicator is labeled with the percent of the turn. This allows for the manual to easily describe desired locations for the students. The dial is on the turn valve so that the indicator can pass 100% to incorporate a large range of flow resistances. The protocol instructs that the students fully close the turn valve and then open it to the desired location on the indicator.
See CAD files here Resistor Measurement Design
LabVIEWThe following LabVIEW image is the current front panel. The file is attached in the link below.
See LabVIEW update here LabView
Test Results Summary
See all Test Plans here Testplans
It was observed that the heart rate was not the same as the input frequency. This is due to losses from the communication from the computer software to the DAQ to the solenoid. The solution to this was to do a calibration using a analog counter for accuracy. Data was collected in sets of beats per 10 seconds. The data was then multiplied by 6 to get bpm and plotted against the input frequency. The trend was linear with a strong linear regression coefficient showing that it is an acceptable fit for this data set. The linear equation was solved in the LabVIEW program so that the input value of BPM provides the needed frequency to the system to get an accurate heart beat. The counter was used again to test the program which proved to fix the problem.
Solenoid Heat Test
Solenoid heat testing was conducted this time with the solenoid inside the box with air and vacuum open. The solenoid was ran using LabVIEW for 6 hours while temperature measurements were taken. As seen by the test chart, the solenoid did not reach the maximum allowable value and followed the same trend as the initial solenoid heat testing. Thus, heat build up because of the enclosed space is not a concern.
Output testing is currently ongoing. Currently the pressure waveforms are accurate and are acceptable shape to model physiological conditions. The flowmeter provides data that fluctuates at time because of the mechanics of the flowmeter. The data does not allow for the integration in the LabVIEW program to generate a P-v Loop. The solution is to provide an example of using MATLAB or Excel to generate a P-v Loop. This is an exercise that the students would complete as part of the post lab.
The current pressure is outputting 120/80 as desired. This was achieved by changing the design of the original compliance tanks in MSD 1 to tanks that can hold desired pressures. As well as, replacing the pinch valve with an in-line turn valve. The turn valve assisted with achieving the desired pressure differential and the ability to change the pressure range.
The majority of problems have been solved. A new common problem of how to measure the compliance with the turn valve was found in this phase. The problem was solved by the information above under resistor measurement.
The problem of ventricle non-uniformity has not yet been solved. The pouring of the silicone is a method that takes practice. It is a trade off of how the mold is designed. Possibilities for future build would be to adapt the design of that it is similar to a casting process.
Updated problem matrix here Updated Problem Matrix
Combined Bill of Materials
See the combined bill of materials here Updated BOM
Plans for next phase
See Schedule here Updated Schedule
Three Week Plans
- Documentation Organization
- Generate User Manual
- Document Build Manual
- Clean-up Drawings with Henry
- Modify compliance ballast
- Document Build Files
- Assist in Build Documentation
- Generate User Manual
- Writing of Technical Paper
- Writing of Technical Paper
- Make LabVIEW Student Friendly
- Email Costumers for a teaching day and demo, Review any problems with user interface and system.
- Create LabViewInterfacing Manual
- Note procedure for DAQ computer heart beat calibration
- Theory of operations in manual
- What is it?
- What influences it?
- What does it influence?
- What does it model?
- Note flowmeter location and why appendix to the build manual
- Move problem 18 to generating solution
- Add user interface to schedule
- On edge for final hand-off show engineering requirements and the results