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Past engineering work explained in more detail.
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Suraj Rama’s
Portfolio The goal of this engineering
portfolio is to supplement my resume and provide further insight to my engineering experiences and skills I have gained in recent history.
Suraj Rama’s Portfolio
Contents
Medtronic Internship ……………………...… 3
Reconfigurable Endoscopic Capsule
Minibots Using Modular Assembly………..…7
Polygraph Machine………………………….13
Wilson Promotional Gyro……………………18
2
Suraj Rama’s Portfolio
Medtronic: Catheter Manufacturing
Inner
Member Middle
Member
Outer
Member
3
Summary - During my internship my focus was to aide in the manufacture of CoreValve, a transcatheter aortic valve replacement delivery system. Our team worked closely with R&D groups in Sana Rosa, CA and Galway to develop a process of manufacture while maintaining needed performance specifications.
Responsibilities - I aided in the manufacturing and testing of several components of the CoreValve delivery system.
Inner Member - Injection molded tips and tensile tested bond
Middle Member - Fused capsules to MM and tensile tested bond
Outer Member - Injection molded tips and tensile tested bond
Suraj Rama’s Portfolio
Problem - The machine would initiate the homing sequence but would not load the recipe profiles. After hitting the stepper control switch the platform would stop and the stepper drive would fault returning a “stepper control error” message. Travel length needed to be extended and password for changing setting needed to be added.
Resolution - Communication to the processor was established via RSLogix 500. The machine was wired to allow for remote access to a Controls Engineer from ADAPT. The program was inspected for faults while running the homing sequence. The logic of the program dictates that the 3 programmable distances for recipes are stored as absolute values, not
relative. Secondly, two consecutive velocities cannot be the same. Logically this makes sense. If P1=10in V1=.5 𝑖𝑛 𝑠 and P2=20in V2=.5 𝑖𝑛 𝑠 then one would combine P1 + P2 for .5 𝑖𝑛 𝑠 .
Travel length and password was added by editing the installed program.
Medtronic: Repaired 6-up Fuser
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Suraj Rama’s Portfolio
Summary - The machine is now in working conditions. Distances 1-3 in the recipe must increase, and any two consecutive velocities cannot be the same. The travel length has been extended to 64.4 inches and a reprogrammable password was added
As seen in the Figure 7, the three positions were all set to 10 inches assuming
the total travel would be 30 inches, however this will cause a fault since the values are not absolute. Additionally, velocity 2 and velocity 3 were equal and therefore would also result in a fault. The proper format is illustrated in Figure 8.
Medtronic: Repaired 6-up Fuser
Figure 9: Left image of PLC board and
right image of machine frontal view Figure 8: Screenshot of Quick Panel
recipe configurations that are
properly programmed
Figure 7: Screenshot of Quick Panel
recipe configurations that result in a
fault
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Suraj Rama’s Portfolio
Problem - Inventory management in the advanced manufacturing
laboratory was a manual process. An up to date inventory list is crucial since many raw materials and components have a long reorder lead time and can often stall engineering builds. Lab needed a non-SAP inventory system.
Resolution - I implemented an automated inventory management solution
using a barcode system. Materials were assigned individual barcodes encoded by Code 39 and ACSII Characters. A Microsoft SQL server was set up for shared data storage. The program inflow was customized for our application and specific reorder points we set up to send reminders to purchasing departments when inventory fell below a threshold value.
Summary - The inventory management
project has been completed and is
currently used by Medtronic’s discrete
manufacturing group.
Medtronic: Inventory System
Figure 10: Diagram of
network setup
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Suraj Rama’s Portfolio
“Reconfigurable Endoscopic Capsule Minibots Using Modular Assembly”
Background - Ingestible capsule endoscopy is a less invasive method of imaging the gastrointestinal tract than traditional tube-
guided endoscopes, and it improves patient comfort and
reduces risk of infection. However, endoscopy capsules have
limited capabilities as a result of short battery life, a non-
repositionable camera, and lack of motion control.
Project – To overcome those limitations, we have designed and prototyped a 4x model that consists of four wirelessly powered
capsules with the ability to attach to one another once
swallowed and assemble into a larger more complex robot.
Partners: Jason Pui and Ben Szewczyk
Figure 1: (A.) CAD
model and (B.) final
assembled
prototype (A.) (B.)
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Suraj Rama’s Portfolio
Approach
We decided to design the robotic system such that there is
one central docking station and several capsules.
Mechanical housing for capsules were designed using
SolidWorks and printed using a 3D printer.
Electronics were designed to fit within housing.
A 4x scale prototype was built and tested for performance.
Individual Responsibilities
Designed individual capsule housing using SolidWorks.
Built 4x prototype of capsule and assembled electronics.
Tested device to verify functional and performance specs.
Designed, built, and tested wireless inductive power system.
Approach and Responsibilities
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Suraj Rama’s Portfolio
Capsule Design
Capsule Design
Initial Design Final Design Prototype Figure 2: Several design changes were made to increase capsule mobility.
The CAD model followed by the actual prototype can be seen above. 9
Suraj Rama’s Portfolio
Wireless Power System
Primary coil generates magnetic field.
Secondary coil receives energy via magnetic
induction according to Faraday’s Law.
B
Primary Coils
Secondary Coil
Figure 4: Primary
(transmitting) coil and
secondary (receiving)
coil
Figure 5: Fabricated coils
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Suraj Rama’s Portfolio
Function
generator
Power
amplifier
Rectifier
Regulator
Receiver System
Wireless Power System
Figure 6: Wireless power system diagram illustrating concept. Inductive power transfer from transmitting coil to receiving coil within capsule.
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Suraj Rama’s Portfolio
Goal - The objective of this project was to measure the galvanic skin response (GSR) of a test subject and correlate that physiological measurement, along with blood pressure and electrocardiogram (EKG) measurements, to ideally test whether a subject was lying or not.
Specific Aim 1 - Determine if the voltage potential and current between two points on skin is measurable
A circuit was designed to trigger an
LED to light up when subject’s skin
voltage potential increased
iWorx GSR-200 was used to detect
skin conductance
Polygraph
Figure 11: GSR circuit design
12
Suraj Rama’s Portfolio
Polygraph
Specific Aim 2 - Develop methods to filter and clean the heart rate and
galvanic skin potential signals
Software
Hardware
Initial measurements through the oscilloscope would merit the use of triggered averaging and moving boxcar averaging to attempt to clear up whichever signal is passed through, e.g. heart rate, GSR, or blood pressure.
The hardware filtering was applied via the iWorx amplifier, using different gains, lowpass and highpass cutoffs in order to find the clearest signal when collecting through the Digital-to-Analog Converter (DAC) board.
Figure 12: Diagram of
filtering and table of filter
cutoffs
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Suraj Rama’s Portfolio
Polygraph
Specific Aim 3 - Test the measuring device on a test subject to detect
physiological response to lying
List of questions was developed and test subject was interviewed
iWorx GSR unit was tested
Correlation between lying and physiological response was calculated
Figure 13: An increase in SNS response increases the conductance by as much as a factor of 2x . This
change is brought about physiologically by an increase in duration and number of sweat glands
opening. 14
Suraj Rama’s Portfolio
Polygraph
Figure 14: LabVIEW program developed to interpret biological signals
15
Suraj Rama’s Portfolio
Polygraph
Figure 15: LabVIEW program successfully returns a message when there was a galvanic skin response
and increased heart rate are detected.
16
Suraj Rama’s Portfolio
Wilson Promotional Widget
A project in Product Design was assigned and required teams to design and
create a promotional widget using a 3D printer.
We chose to create a gyro used for arm workouts since tennis players are the main target market for Wilson. In addition we thought designing and printing the gyro in one piece would be interesting and challenging.
Figure 16: Final model of gyro ball
and stand Figure 17: Front face of gyro with Wilson logo
engraving
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Suraj Rama’s Portfolio
Wilson Promotional Widget
The final design had a stand used to start spinning the gyro. The stand served
the role of also displaying the Wilson logo and made the storage of the gyro more user friendly. The tolerances between pieces needed to be accurate according to printer specifications since it was printed in one piece.
Figure 18: Stand contains motor
and spins the gyro to high velocity
Figure 19: Mechanics of gyro are illustrated in these images. The gyro can rotate
freely on two axes.
18
Suraj Rama’s Portfolio
Wilson Promotional Widget
Only the initial design was printed. After a design review we chose to market
the product to Wilson, a company better oriented to our product. Then we made changes to arrive to our final design which was seen earlier.
Conclusion: The prototype was capable of rotating freely and the gyro
generated a force large enough to give forearms a work out.
Figure 20: Initial design prototype
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