Overview of Status of Analysis, Design, Fabrication, Tests, etc.
After meeting at DJO the team has decided to move forward with the 4-bar linkage design. We are now working with DJO to determine if we want to pursue a vertical or horizontal design.
We are also considering a method for covering the joint that involves three layers of material. A base layer that will be come the knee, a foam layer that will simulate muscle tissue and a neoprene sleeve to cover the surface.
Accomplishments from Previous Week
After analysis it was determined that the cable pull actuation method is viable but despite this we have decided to drop it due to motor fatigue concerns.
Goals for Next Week (list names after each item). Use specific and measurable objectives.
CAD model and acrylic scale model (cut with Lasercamm). - Brian/Chris
CAD model and 3D printout of covering. - Randy/Chase/Meagan
Determine which cots parts can be utilized for 4-bar linkage design. - Meagan
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments
The speed of the tester was a concern brought up and through email communication we have proposed to run the tester at normal human cadence. "Ideal cycling frequency range is 1 to 1.5 Hz (1,000,000 cycles complete in 7.7 - 11.5 days)."
Instructor Comments from Last Meeting and Actions Taken to Address these Comments
Concerns of ligament stretch in actual knee: Based on DJO feedback the main goal is to test the braces in absolute values of max and min stretch based on knee rotation. The individual ligament testing is dont with other experiments at DJO and would not be overly informative in a long duration cycle test.
The existing tester shown in the project proposal is not a cycle tester, and is hardly even utilized for current DJO tests. However it would still be beneficial to use it to display how the braces can collapse in a mechanical joint and so we will use it to illustrate this point at our next DJO visit.
Risks and Areas of Concern
"Flesh and skin" compatibility with 4-bar design.
Sensor placement in a 4-bar system.
Torque distribution in a 4-bar system.
Data Acquisition/sensor system.
Motor
Resources or Information Required but not Available
Labspace at DJO for the cycle tester - will determine if we pursue horizontal or vertical design.
Ideal amount/length of leg portions to create on cycle tester.
Schedule
Describe upcoming milestone
Update Gantt chart.
Budget (list amount spent and amount remaining)
$5.94 PVC from Home Depot
Progress on Report and Webpage
Webpage updated 1/11/2012