Week 6

     One of the things we did this week was redesign the electronics casing so that it was smaller. Our client/adviser agreed that only one motor unit would be sufficient for demonstration (in addition, an extra leg brace for the other leg could be printed, allowing the astronaut to simply switch the motor system between the two). Since the old casing was designed to hold two of everything, the new casing is about half the width. It also includes holes for the "kill switch" to be easily accessible, as well as a port through which the microUSB on the Arduino can be accessed. The updated casing can be seen in the images below.

The Arduino's microUSB can easily be accessed, as well as the "kill switch" that will stop the motor.

This view shows all of the components placed in the casing. The lid (not pictured) slides onto the box via notched grooves, as in Revision 1 of the casing.

     We also finished designing the double weight system this week, which is the redesign that attempts to minimize the wiggle produced when the motor is run. This system uses two brass masses, each roughly half the size as the original brass weight. The masses are spun in opposite directions, via the motor and two attached gears. As can be seen in the image below, this system is much bulkier than the original system, but will hopefully vastly reduce the axial rotation created. 

The redesign will also attach to the leg brace via a long "arm."

This view shows the two brass weights and the gears more clearly.

The entire system will have a casing around it, to help improve safety. This makes the overall system much bulkier, but will hopefully help reduce/eliminate the wiggle.

     This week we also went to Dr. Kim's lab to use the force plate again. We were trying to see if the force generated was transmitted to the upper leg/femur. One way we thought to test this was to have Isaac sit on the force plate with his legs raised in the air. We then collected readings will his legs straight and locked, and then with his legs bent. We were hoping to see similar readings for both cases. However, the data we received was inconclusive and would require additional testing/possible testing with the redesigned system.

Isaac standing on the force plate with the motor system on his left leg. Shown in his hand is the new electronics casing (he did not wear it as he did not have a belt).

Isaac sitting on the force plate with his legs bent and his feet elevated  above the ground.

     Finally, we updated Deliverable 6, turned in the Midterm Notebook, and worked on the Midterm presentation this week. The midterm presentation will be presented on Monday at the beginning of Week 7 (Feb 27, 2017).