Week 5

     During class this week, we were able to spend a good amount of time talking to Dr. Gordon and showing him our progress thus far. We were also able to run the motor system (with Isaac wearing it on his leg). The main concern with the motor system currently is that it produces a fair amount of wiggle in the leg. This could become uncomfortable; however, if the astronaut is only wearing the device for short periods (15 minutes) at a time, then this may not be the highest priority, so long as the system works. The second concern with the wiggle is that excess force may be getting transmitted in the horizontal directions (rather than vertically, along the axis of the leg). This could be tested and checked by running the system on the force plate again, however, as it has the ability to record force in the x, y, and z-directions. (Additionally, Dr. Kim was able to show us a way to export the data this week).

The motor system shown on Isaac's leg. The entire system (and leg) wiggled/vibrated when the motor was turned on. 

     Dr. Gordon suggested another method that could be used to help combat the wiggle. He suggested spinning two weights at once, and using gears to mechanically ensure that the motors were in phase. Since the class is scheduled to allow a couple weeks for testing and verification, and since our system has very few ways to test it, he thought that we would have the time to be able to look into and possibly do this. As for our current progress, Dr. Gordon felt that we were in a good spot for the semester.
     We had been planning on purchasing the items needed to create a second motor assembly for the right leg, but we decided to postpone this (possibly indefinitely) in case we need the budget for gears or additional brass, and because it would be possible to switch the same unit between the two different legs (running them at different times). However, we did purchase some additional items, most of which will be used for our current set-up. This includes the items shown in the table below.

Items ordered this week.

     We also created an up-to-date budget that includes all of our purchases to date and the amount of money spent so far. To date, we have spent $370.49, out of an original $600. This budget was part of the requirements for Deliverable 6.
     Additionally, a box was designed in Solidworks to hold all of the electronic components (for testing, we have simply been having the user hold them). The box has a loop on the back that will fit around the wearer's belt loop, and can be worn at the back. There is a lid that slides on and off via notched grooves in the box, and holes for wires to enter and exit the box. The next version of the box will need an additional hole for the on/off switch to stick through, making it easily accessible to the user. The size of the box was determined by the size of the components that will need to be placed in the box. This can be seen in the images below.

The electronics box with lid.

The electronics box with lid. There is a hole for wires on the bottom of the box and a loop through which a belt can fit through.

The lid is slid off to show the contents of the box. It will hold the motor battery, Arduino battery case, breadboard (with Arduino and other components), and motor controllers). 

     We also started looking at and designing the double-weight system this week, and worked on Deliverable 6 (due 2/20). We decided that the gears for the double-weight system can be 3D printed for now.