Testing
Warning!
Images below contain blood and exposed leg muscles.
On 4/19/2021 the system was ready to be tested. The assistance of Dr. Janes from the veterinary diagnostics lab at the University of Kentucky was required to provide a horse leg cadaver for testing. The purpose of this test was to verify that the system would be able to gather acceleration data at multiple points along the leg and at different frequencies.
Testing Procedure
In order to test the system Dr. Janes brought in a horse cadaver leg and it was attached to the frame with the voice coil being placed under the leg and with the hoof in the center of the voice coil. After the leg was securely attached to the frame then three accelerometers were drilled into different bones in the horse leg. The accelerometers were attached to the short pastern bonce, long pastern bone, and the cannon bone so that the vibrations through the pastern joint and fetlock joint could be measured. Once the leg was attached and the accelerometers were connected the voice coil was vibrated at 5 different frequencies: 3.5Hz, 7Hz, 14Hz, 28Hz, and 56Hz and data was gathered from the accelerometers. The data was exported to excel for analysis.
Results
The system was successful and data was able to be gathered from the different accelerometers. Initial review of the data shows that the most variation between the accelerometers occurs when the frequency is low, while high frequencies show little to no variation between the accelerometers. The full data file can be viewed by clicking on the google sheets on the left. A video of the a test running can be seen below.
Complications
While the overall testing was successful there were several items that came up during testing that were unforeseen and disruptive. The first issue was that the cadaver's femur had a diameter too large to fit into the previous groups clamp and so the clamp would not close and hold the leg properly. The only solution to this problem was to use a saw to decrease the diameter of the femur until the clamp was able to securely hold the leg in place.
The other complication that arose during testing was the attachment of accelerometers. The problems came from the fact that the bone and the skin of the cadaver could move independently of each other, this meant that the skin could move while drilling into the bone and cause the hole to not be in the right location (issue shown in the video below). The only solution to this issue was to try and hold the skin as tight to the bone as possible while drilling, but this solution was not perfect and the drilling procedure still took a lot more time than anticipated. With the attachment procedure proving to be more difficult than anticipated only three accelerometers were attached to the horse leg instead of the intended four so that the process could be shorted and testing could continue.
FullTest.MP4In this video a screw is trying to be drilled into the bone, but the skin moves and causes the screw to miss the bone entirely. This can be seen at the end of the video.
ScrewingIntoSkin.MP4