A Portable Test Fixture for the Medtronic Signia Surgical ......A testing protocol was developed to...
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References Acknowledgements We would like to thank our advisor, Prof. Joseph Palladino and our Medtronic contacts, as well as Prof. John Mertens, Andrew Musulin, and Nancy Fleming for their great support. ➢FEA (CFD) Simulation ➢Valve Angles ➢Re-design of the Adapter ➢Force - time Profiles ➢Verification & Validation A testing protocol was developed to prove the test fixture functions properly. A test fixture that is transportable, mechanical, and provides unit-step constant resistive forces was successfully built. Repeatability and durability testings are being conducted. Conclusions A Portable Test Fixture for the Medtronic Signia Surgical Stapler Christopher Mulhern ’17, Hieu (Hugh) Nguyen ’17, Tristan Peirce ’17, Robert Tella ’17 Advisor: Joseph Palladino, Ph.D. Industrial Sponsor: Jennifer McCabe, Thomas Wingardner, Medtronic Inc. ➢Pugh Matrix: The matrix compares each design idea to the test fixture from the previous generation for a series of weighted criteria on a scale ranging from -2 (much worse than) to 2 (much better than) the existing benchmark design. The hydraulic cylinder won over the other design ideas. ➢Governing Equations: ➢Determining Valve’s Opening Angle ➢Verification & Validation ● Verification: Confirm each requirement is met (built properly?) ● Validation: Confirm Medtronic’s needs are met (right system?) ➢Final Design ● Laparoscopic surgery is a common procedure for removal of abdominal organs. ● 700,000 people have their gallbladder removed by laparoscopic surgery each year.[1] ➢Medtronic Signia Surgical Stapler: A laparoscopic device that clamps, staples, and cuts tissue ➢Problem Definition and Objectives: ● Current test fixture is stationary, big, and expensive ● Design a portable testing fixture that is able to: ○ Provide four constant resistive forces at four advancement speeds of the firing rod ■ 1 clamp test ■ 3 different firing tests ○ Display force data ○ Be transportable ● Design Constraints: ○ Simple to use ○ Safe to use ○ Compatible with Signia power handle ○ Durable (survive 100,000 tests) ○ Contain minimal electrical components ○ ➢Alternative Design Solutions: Introduction Methods (cont.) Results Figure 1 : (a) Medtronic Signia Surgical Stapler Courtesy of Medtronic Inc.(b) Surgical stapler used in laparoscopic surgery [1] Elwood, David R. "Cholecystitis." Surgical Clinics of North America 88.6 (2008): 1241-1252. (a) (b) Figure 3 : Possible design solutions: (a) Piston-cylinder (b) Eddy Current Brake (c) Constant Force Spring Methods (a) (b) (c) Results (cont.) ● Calculate required flow coefficient for each force-velocity profile ● Determine the relationship between valve angle-flow coefficient (Cv) ● From the valve angle-Cv curve, back-calculate the required valve angles corresponding to the required flow coefficients Figure 5 : Experimental setup that relates valve angle with flow coefficient Figure 4 : A depiction of the fluid flow inside the hydraulic cylinder Figure 6 : (Left) CAD of the final design. There are four flow paths for three firing forces and one clamping force path. (Right) The physical design Figure 8 : Experimental relationship between flow coefficient (Cv) and valve angle. The three calculated Cv were lying in the ‘region of interest.’ The corresponding valve angle for each Cv was linearly interpolated. Figure 9 : (Left) Medtronic’s current adapter that hooks up to the firing rod. (Right) The new design enabling retraction of the piston rod. 0.6 K v = C v Figure 7 : CFD analysis of the forward motion of the firing rod and piston. The flow trajectories are depicted by the colored paths. Numerical results were used to size adjustment valves and to determine that viscosity of the working fluid did not significantly affect pressure differential across the adjustment valves. Figure 10: Measured resistive force vs. time. Unit-step-like profiles were obtained. Numerical results are not disclosed per request of the project sponsor. Time (s) Force (lbf)
Transcript of A Portable Test Fixture for the Medtronic Signia Surgical ......A testing protocol was developed to...
References
Acknowledgements We would like to thank our advisor, Prof. Joseph Palladino and our Medtronic contacts, as well as Prof. John Mertens, Andrew Musulin, and Nancy Fleming for their great support.
➢FEA (CFD) Simulation
➢Valve Angles
➢Re-design of the Adapter
➢Force - time Profiles
➢Verification & Validation A testing protocol was developed to prove the test fixture functions properly.
A test fixture that is transportable, mechanical, and provides unit-step constant resistive forces was successfully built. Repeatability and durability testings are being conducted.
Conclusions
A Portable Test Fixture for the Medtronic Signia Surgical StaplerChristopher Mulhern ’17, Hieu (Hugh) Nguyen ’17, Tristan Peirce ’17, Robert Tella ’17
Advisor: Joseph Palladino, Ph.D.Industrial Sponsor: Jennifer McCabe, Thomas Wingardner, Medtronic Inc.
➢Pugh Matrix:The matrix compares each design idea to the test fixture from the previous generation for a series of weighted criteria on a scale ranging from -2 (much worse than) to 2 (much better than) the existing benchmark design. The hydraulic cylinder won over the other design ideas. ➢Governing Equations:
➢Determining Valve’s Opening Angle
➢Verification & Validation ● Verification: Confirm each requirement is met (built properly?)● Validation: Confirm Medtronic’s needs are met (right system?)
➢Final Design
● Laparoscopic surgery is a common procedure for removal of abdominal organs.
● 700,000 people have their gallbladder removed by laparoscopic surgery each year.[1]
➢Medtronic Signia Surgical Stapler: A laparoscopic device that clamps, staples, and cuts tissue
➢Problem Definition and Objectives: ● Current test fixture is stationary, big, and expensive● Design a portable testing fixture that is able to:
○ Provide four constant resistive forces at four advancement speeds of the firing rod ■ 1 clamp test■ 3 different firing tests
○ Display force data○ Be transportable
● Design Constraints:○ Simple to use○ Safe to use○ Compatible with Signia power handle○ Durable (survive 100,000 tests)○ Contain minimal electrical components○
➢Alternative Design Solutions:
Introduction Methods (cont.)
Results
Figure 1: (a) Medtronic Signia Surgical Stapler Courtesy of Medtronic Inc.(b) Surgical stapler used in laparoscopic surgery
[1] Elwood, David R. "Cholecystitis." Surgical Clinics of North America 88.6 (2008): 1241-1252.
(a) (b)
Figure 3: Possible design solutions: (a) Piston-cylinder (b) Eddy Current Brake (c) Constant Force Spring
Methods
(a) (b) (c)
Results (cont.)
● Calculate required flow coefficient for each force-velocity profile
● Determine the relationship between valve angle-flow coefficient (Cv)
● From the valve angle-Cv curve, back-calculate the required valve angles corresponding to the required flow coefficients Figure 5: Experimental setup that
relates valve angle with flow coefficient
Figure 4: A depiction of the fluid flow inside the hydraulic cylinder
Figure 6: (Left) CAD of the final design. There are four flow paths for three firing forces and one clamping force path. (Right) The physical design
Figure 8: Experimental relationship between flow coefficient (Cv) and valve angle. The three calculated Cv were lying in the ‘region of interest.’ The corresponding valve angle for each Cv was linearly interpolated.
Figure 9: (Left) Medtronic’s current adapter that hooks up to the firing rod.(Right) The new design enabling retraction of the piston rod.
0.6 Kv = Cv
Figure 7: CFD analysis of the forward motion of the firing rod and piston. The flow trajectories are depicted by the colored paths. Numerical results were used to size adjustment valves and to determine that viscosity of the working fluid did not significantly affect pressure differential across the adjustment valves.
Figure 10: Measured resistive force vs. time. Unit-step-like profiles were obtained. Numerical results are not disclosed per request of the project sponsor.
Time (s)
Forc
e (lb
f)
