Week 8 Update

 Mohammed: This week the group doubled down with research targeting motors that would fit the requirements of the Exoskeleton. Thanks to the help of Professor Gordon we were given a better estimate on the range of the budget. Professor Kim's advising helped get us focused onto the biggest hurdle we had, which is the pool of motors at hand. Most of the time implemented with this week will be to enforcing the proper motor into the project and to test portions of the product we have at hand from the recent shipment.

 

 

 

 Brad: This week we had started with looking into several types of different motors that would work, such being either stepper motors or DC brushless motors. This had taken up a good chunk of time during class as well as a day outside of class looking into which of the two to choose from. Aside from that, we had looked into several journals for Dr. Kim in regards to which motor to choose as well as the development of several exoskeletons that have already been developed. From this, as a team we have all found that the two most common motor types for an active hip is either an stepper motor or a DC brushed or brushless motor to go in place. There have been several companies that we have reached out to to see what the cost of a motor would be if we placed an order for two to use for this capstone project but have yet to hear back from them. Later in the week we had conducted the first round of our shakedown testing on the weight lifting belt as well as the Velcro straps for the upper thigh. The results from this shakedown testing were unfortunately not in our favor with the strap being something that we'll need to look more into in a tighter design, or one that can hold a bar without rotating as much on the leg. in regards to the belt, we'll need to either look into a different design that would prevent the belt from pushing into the individual when a torque is applied as well as something that would attach to the two motors such as a torsion bar to take the flex of the motors into account.

Natalie: This week our main priority was to research and determine what motor we will order as a team to test for our first design iteration. Since we don't have professors at CBU with an intensive knowledge of motors, I reached out to my summer internship supervisor for any recommendations on what direction to go. He said that if we wanted a high torque and good position control, a stepper motor along with an Arduino control board would be a great choice for our exoskeleton. After receiving this information, I continued researching stepper motors to see if previous exoskeletons had incorporated stepper motors into their design. I noticed that for upper body exoskeletons it was common for stepper motors to be used, however our focus is lower body so I looked into if it would provide enough torque. Our goal torque was 25 N and there were many stepper motors that exceeded that, and in comparison to DC motors the price is much cheaper and more cost effective for testing purposes. Based on that and after talking to Dr. Kim, we have decided to order a stepper motor for our testing so that the momentum of our project continues to move us forward. 

Here is the link to the main journal I referenced when discussing with Dr. Kim: https://www.researchgate.net/publication/285475351_Upper_Limb_Exoskeleton_Controlled_by_Stepper_Motor


Fig. Natalie: I drew up the design iteration 1 for our exoskeleton. 


Chris: Other than what has already been talked about by other member regarding the meeting we had with Dr. Kim and with each other on the furthering of the motor research and the narrowing down of our choices. I spent the week looking at possible fabrication methods and determining possible final selections for different materials and processes for our design. We have decided that an aluminum frame and 3D printed casing components would be the best option due to price and workability. Also we decided to go with a mechanical knee brace, which we will augment for our purposes, as our lower limb attachment point for our exoskeleton, meaning fabrication will require attachment of this portion of the device to the body. We also looked into possible "overalls" or a vest style attachment for the actual exoskeleton to the body in conjunction with a belt of some kind, which we had previously been thinking of using. I found products for these that can be modified and used in our project, they can be shown in class during our meeting time and will make their way into the blog once we decide on a final product for each by this week, and order those parts.











 

 

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