Engineering Portfolio


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Past engineering work explained in more detail.

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Engineering Portfolio

  1. 1. 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.
  2. 2. Suraj Rama’s Portfolio Contents Medtronic Internship ……………………...… 3 Reconfigurable Endoscopic Capsule Minibots Using Modular Assembly………..…7 Polygraph Machine………………………….13 Wilson Promotional Gyro……………………18 2
  3. 3. 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
  4. 4. 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 4
  5. 5. 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 5
  6. 6. 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 6
  7. 7. 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.) 7
  8. 8. 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 8
  9. 9. 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
  10. 10. 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 10
  11. 11. 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. 11
  12. 12. 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
  13. 13. 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 13
  14. 14. 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
  15. 15. Suraj Rama’s Portfolio Polygraph Figure 14: LabVIEW program developed to interpret biological signals 15
  16. 16. 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
  17. 17. 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 17
  18. 18. 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
  19. 19. 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 19