Category: Rhea Status Reports

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I made the surveys for the device usability and comfort, and collected responses from different participants to get an idea of whether or not the shank-mounted device met our use case requirement of being unobtrusive while walking. I also worked with Iqui to make more of the soft cases for the shank-mounted device for use during the demo – I fabricated 3 sets of cases just in case one of them rips during the demo.

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is on schedule; all that is left to do this week is final assignments (video, poster, paper). 

What deliverables do you hope to complete in the next week?

1. Finish final poster
2. Prepare for demo
3. Finish final report
4. Finish final video

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

Finished fabricating cases for both the foot mounted and shank mounted components. These components are currently adhered to the user using tape, but the next iteration of the case will have a slot for a velcro strap for the foot mounted device. I also finished soldering the MCU/IMU component with the battery and on/off switch. I had to resolder the MCU for the shank mounted device since the battery was not soldered on the right pins to allow for charging capabilities through the MCU usb-c port. 

Started testing the device with Lakshmi, Kaitlyn, Vu, and Iqui. We conducted the following tests: 

• FPA accuracy testing: 
  • Treadmill walking at baseline walking speed with the foot mounted device 
  • Treadmill walking at 20% slower than baseline walking speed 
  • Treadmill walking at 20% faster than baseline speed 
  • Overground walking 
• Intuitive feedback testing: 
  • Treadmill walking at 20% slower speed, verbally instructed participant to walk with their toes pointed inward 
  • Treadmill walking at 20% slower speed, verbally instructed participant to walk with their toes pointed outward
  • Treadmill walking at 20% slower speed, participant walked with their toes pointed inward based on vibrotactile feedback 
  • Treadmill walking at 20% slower speed, participant walked with their toes pointed inward based on vibrotactile feedback 
• Gait retention testing: 
  • Treadmill walking with toes pointed inward immediately after receiving vibration cues on how to walk toe in 
  • Treadmill walking with toes pointed outward immediately after receiving vibration cues on how to walk toe out 

The tests were done with the motion capture system as well – I preprocessed/labeled all of the motion capture data after each experimental session. After FPA accuracy testing, we compared the results from the device estimated FPA vs. the mocap ground truth. After intuitive feedback testing, we compared the FPA of the user without any feedback vs. receiving feedback to see if the vibrations were helpful to the user to learn how to adjust their walking. 

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is on schedule, as we have been conducting testing with the mocap system all of next week. 

What deliverables do you hope to complete in the next week?

1. Conduct second round of testing with a new participant 
2. Finish analysis of gait retention data 
3. Finish slides for final presentation 
4. Start working on final poster 

As you’ve designed, implemented and debugged your project, what new tools or new knowledge did you find it necessary to learn to be able to accomplish these tasks? What learning strategies did you use to acquire this new knowledge?

We recognize that there are quite a few different methods (i.e. learning strategies) for gaining new knowledge — one doesn’t always need to take a class, or read a textbook to learn something new. Informal methods, such as watching an online video or reading a forum post are quite appropriate learning strategies for the acquisition of new knowledge.

At the beginning of the semester, I wasn’t very comfortable with soldering (I had done it a few times before, but not as much as required for this project). So a lot of what I was learning (how to solder an on/off switch, how to solder a battery onto an MCU, etc.) were things I learned both through Youtube tutorials online as well as tutorials and suggestions online. 

The MCU for the shank component also ran into issues where it wasn’t being recognized as a device when I plugged it into a laptop. I realized that the MCU was bricked, and was able to find a forum post from 2020 where someone ran into a similar issue and was able to unbrick the MCU so that it could be recognized as a device to be programmed. 

This was also the first time I was making a soft case, so I learned the methodology of making a case using liquid silicone. With Iqui’s guidance, I learned how to use the centrifuge to mix the liquid silicone materials together to then cast it into a mold for the soft case. 

A lot of the learning strategies I used to acquire this knowledge involved how to look things up effectively with different keywords/phrasing for the questions to get the best results I am looking for. I also asked for a lot of help from mentors such as Vu and Iqui for guidance as they also had resources from previous experiences that could help me when I got stuck or had questions for design decisions. Most of what I was working on required a lot of trial and error. 

It was also necessary to learn the background information related to gait retraining and how vibrotactile feedback cues work/are perceived by humans. This required an extensive literature review to understand the fundamental background knowledge to be able to apply it to the project. I went through and read the recommended papers sent by Dr. Halilaj and also conducted some of my own literature reviews. 

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I finished soldering the MCU/mux component with the battery and an on/off switch to take it off the breadboard and make the vibrotactile component fully wearable.

I also worked on writing up an experimental protocol for us to start testing next week and met with Vu to get his feedback on the protocol. 

I met with Iqui to fabricate more cases – we ended up changing the fabrication protocol such that the liquid silicone mixture will get run through the centrifuge twice (instead of once) so that it is fully mixed, since last week we had issues where the silicone wouldn’t cure even after 24 hours. The design of the mold was also adjusted as well to reduce the larger air bubbles. Instead of pressing the positive of the mold into the negative from the top, the positive will get pressed into one half of the mold and the second half is put in place on top of it (like a sandwich). 

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is on schedule, as we will begin conducting testing with the mocap system all of next week. 

What deliverables do you hope to complete in the next week?

1. Solder the MCU/IMU component with a battery and on/off switch so that the foot mounted component can be worn without needing to be connected to the laptop. 
2. Run experiment for testing FPA estimation accuracy 
   1. Label the motion capture data to be processed using Lakshmi’s mocap vs device FPA code 
3. Make a case for the foot mounted device 
   1. If this does not get done before the experiment on Monday, we will fir

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I met with Iqui multiple times this week to fabricate 5 more soft cases made out of the liquid silicone. I was running into issues where a significant number of air bubbles would get trapped in the mold, resulting in holes in the liquid silicone after it cured. 

I worked on fabricating a new mold for the case based on Dr. Halilaj’s feedback (rounded edges, slightly thicker) and have been working on trying different methods for the case to get rid of the large air bubbles. 

I also discussed with Vu different options for the device adhesive. The wig tape I was intending on using did not stick to the soft silicone material well – it was easily peeled off and removed. As an alternative, I proposed using adhesive/tape used for attaching glucose monitors onto an individual’s arm instead of the wig tape we originally proposed. The glucose tape seemed to work well and stuck to the soft case. 

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is behind since the soft cases I have been fabricating are not ready yet for the device to be fully wearable. This weekend I am planning on making more soft cases such that the whole device can be taped onto the shank for testing. 

I am also slightly behind with resoldering the MCU/mux component with the battery to take it off the breadboard since the parts we ordered went missing for a few days, however I found the parts so I will work on that early next week. 

What deliverables do you hope to complete in the next week?

1. Prepare for demo 
2. Resolder the MCU/multiplexer and attach the battery with the switch so that I can take the MCU off the breadboard 
   1. Print a case for the MCU+mux+battery to make it fully wearable
3. Make new versions of the soft case and find a way to remove bubbles from the silicone 
   1. Make enough cases for both the left and right LRAs 
4. Write up experimental protocol for the user testing of the device 

What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I met with Iqui multiple times this week for assistance on designing the mold for the case as well as learning the fabrication process. We made 3 different versions of the case using 3 different materials and fabrication methods. 

1. Hard Case: 3D printed TPU 
   1. This version was the most rigid out of the three, so it absorbed a lot of the vibration when testing different vibration sequences
   2. It is the most sturdiest and most reusable material
2. Hard flex case: 3D printed soft resin 
   1. Semi hard/semi flexible case 
   2. Also still absorbed a decent amount of the vibrations, making it harder to perceive 
3. Soft case: liquid silicone that was cured/casted in a separate mold 
   1. The most user friendly/comfortable out of all the cases due to the squishy material
   2. Also the most fragile since it is so soft, which means it could end up tearing/ripping even during one session 

After meeting with Dr. Halilaj with the group, she suggested that we focus the most on the soft case since it is the most wearable out of the three options. 

Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

My progress is on schedule since I planned on finishing the case fabrication for the LRA+haptic drivers by the end of this week. 

What deliverables do you hope to complete in the next week?

1. Resolder the MCU/multiplexer and attach the battery with the switch so that I can take the MCU off the breadboard 
2. Print a case for the MCU+mux+battery component to make it fully wearable 
3. Print different versions of the soft case with varying thicknesses 
   1. Make enough cases for both the left and right LRAs

What I accomplished this week:

The majority of my time for the first half of this week was spent working on the ethics assignment.

I also further discussed with Iqui about creating the soft case on Thursday; specifically, he gave me suggestions on how to design the mold for the case. I plan on making a case similar to this design:

I have never 3D printed anything before, so I spent a lot of time this week doing research on how to get started with 3D printing and making a CAD design for a mold that can get 3D printed. I went through multiple beginner SolidWorks Tutorials as well as a LinkedIn Learning introductory tutorial to become familiar with the software to use it for making a CAD of the mold.

On schedule? 

No, I am behind schedule for prototype fabrication. The plan was to finish developing a few different versions of the case by the end of this week, but I was set back due to the learning curve of how to use CAD and 3D printing, since I have never done either before. To catch up, I have already done multiple tutorials on how to use SolidWorks, so I feel more confident in being able to easily make a design for the mold. I will meet with Iqui again earlier next week (Monday or Tuesday) to get feedback on the mold design and 3D print it by Wednesday so that the soft case can be completed by Friday.

Objectives for next week:

1. CAD 3 different versions of the soft case mold to be printed by Wednesday
   1. Meet with Iqui to get feedback on the deign for the mold before printing
2. Fabricate the soft case using the molds and the liquid silicone that was delivered last week
3. Write up an official experimental/testing protocol for the prototype testing (treamill walking, motion capture, overground walking scenarios)
   1. Get feedback from Dr. Halilaj if any adjustments need to be made for the experimental protocol before officially conducting tests

What I accomplished this week:

This week majority of my time was spent working on the design review report. Specifically, I worked on the following sections: Abstract, Related Works, as well as all the sections related to the shank-mounted wearable and the vibrotactile feedback throughout the report.

I met with Vu and Iqui this week with Kailtlyn to discuss 3 different methods for creating the soft case for the hardware components (outlined here). After this discussion, I decided that the best method for making the case is to 3D print a mold for the case (given the dimensions of the actuator system and the central component) and create the case using the mold and liquid silicone.

On schedule? 

Yes, I am on schedule for prototype fabrication. We recently ordered a second round of parts specifically for the foot-mounted device as well as the soft case, and will begin prototyping different versions of the case after the team is back from spring break.

Objectives for next week:

1. Fabrication of different models for the case mold. I aim to make 3 versions of the soft case
2. Solder the new hardware components
   1. 2nd Seeed Studio MCU/IMU
   2. Integrate the on/off switch into the shank-mounted wearable
3.  Develop vibration command sequences for the left and right LRA and test to see which vibration pattern and waveform is the most detectable

What I accomplished this week:

I practiced my presentation and presented the Design Review slides on Wednesday.

This week I integrated the second LRA and haptic driver with the current prototype for the shank (last week’s version only had one LRA being controlled by the MCU). This allows for the MCU to send vibration commands to either the left or right LRA using a mux. We also received the parts we ordered, so I was able to connect the circuit to the battery and have it run wirelessly without needing to be plugged into the laptop for data transmission.

After discussing with Dr. Melissa Orta-Martinez as well as a PhD student in her lab, Iqui, I started doing research for how to encase the hardware components that will be the most “wearable”. I looked into different materials to make a soft case compared to a hard case that has been used in previous studies.

On schedule?

I’m on schedule in terms of the hardware for the prototype (putting together both LRAs for the shank component and the IMU for the foot). However, I am behind in terms of fabricating the sleeve/cases for the components to be worn on the user’s leg. This was something I wanted to start this week. In order to make up for this, I will be able to use the slack time we built into our schedule to first finalize the plans for the soft case and order the parts early next week to start fabrication.

Objectives for next week:

1. Finalize the plans for fabricating the soft case after discussing with Iqui one more time
2. Order the parts for the soft case
3. Develop vibration command sequences for the left and right LRA and test to see which vibration pattern and waveform is the most detectable
   1. For now, I will place the entire breadboard and circuit on my leg using wig tape that we have borrowed from Iqui
4. Complete the Design Review Report

What I did:

• Soldered the MCU, haptic driver, and multiplexer. Soldered the connections between the haptic driver and the single LRA
• Put together each individual hardware component to work together with Lakshmi’s code
  • Connected the haptic driver+LRA to one channel of the multiplexer to allow for sending commands to 2 separate haptic driver + LRA components for both sides of the leg as part of the device
• LRA vibration testing
  • Read through the documentation for the haptic driver we are currently using (DRV2605), as it contains a library of preset vibration commands to drive the LRA that can be put into different sequences for different types of vibration feedback (sinusoidal, ramp up, constant, pulsing, etc.)
• Tested the vibration feedback from the LRAs with Lakshmi using her code/pipeline to send vibration commands from the MCU to the haptic driver
  • The LRA feedback was too faint to detect a difference among the different vibration commands,
  • I debugged this issue by changing the pin the haptic driver was connected to (originally it was connected to the 3V pin, but I then adjusted it to V_in, which supplies 5V)
• LRA type comparisons
  • Conducted literature review on different types of LRAs and their vibration amplitudes to see which models could provide the most detectable vibration amplitudes
• Worked on Design Review presentation slides
  • Worked on the solution approach slides by compiling the information we have on hardware component comparisons (different LRAs, MCUs, IMUs)

On schedule?

I am on schedule based on our project timeline, as I have connected the necessary hardware for the device that will be worn on the shank and integrated it with the current code. I also worked on testing the LRA vibration commands. After discussing with the group, we agreed to shift around when I will start building the sleeve for the LRA by another week since ideally the hardware components for the device worn on the shank will be connected first. I also still need to look into tradeoffs between an adhesive attachment vs. using a strap for the attachment.

Next week’s deliverables:

• Present Design Review in class
• Solder the second LRA and haptic driver
  • Integrate the additional haptic driver to the current system
  • Test vibration intensities with the 2 LRAs
• Solder the IMU/MCU components to be worn on the foot for the FPA estimation
  • Comparison between adhevise vs. strap to attach the device on the shank

• What did you personally accomplish this week on the project? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).

I assisted with compiling the parts list to being prototyping. The current MCU chosen is a single-core MCU with an integrated 6 DoF IMU that is capable of BLE+WiFi data transmission. An alternative MCU has also been ordered that is a dual-core MCU, but it does not have a built in IMU, which means that the size of the prototype would have to increase if the MCU and IMU were separate components.

I also met with Dr. Eni Halilaj with the group to get some guidance on the project and feedback on high level goals that were listed in our Gantt Chart and proposal presentation.

I conducted literature review to learn more about foot angle progression (FPA) estimation by reading the following paper. I also start planning out the BLE data transmission pipeline from the laptop to the MCU, as well as how to set up the connection between the MCU and the haptic driver.

• Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?

Currently, my progress is on schedule since I already had the single-core MCU to start testing and working with while waiting for the other parts we have ordered to arrive.

• What deliverables do you hope to complete in the next week?

I hope to start working on connecting the MCU to the haptic driver with a breadboard at first as a proof of concept.

I also plan to work on developing the MCU —> laptop pipeline using the single core MCU that we have, and that code will ideally be easily translated to another MCU if we decide to go with the dual-core MCU instead. As part of this, I will work on implementing code for BLE data transmission between MCU —> laptop to plot test/sample data before transitioning to having it display the raw IMU data.

Finally, I will conduct further literature review on FPA estimation and a previous study’s algorithm for this calculation and how to integrate their approach for our device components. The code will be added and updated to the project’s GitHub repo.