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Key Questions
Key Questions
Would this product make users feel more comfortable when going out solo?
Would users trust this product in dry ground? What about other ground types?
Is it comfortable to get in and out for our user demographic?
How much effort do users consider this product? Easier than burying a tire?
Would users pay ~$50-75 for this?
Where would users store this in the vehicle? Any there any concerns?
Initial Prototypes Built
Initial Prototypes Built
Overall, we were able to utilize the leftover steel on hand from our pretotyping phase to save cost. Additionally, we purchased some 2" steel for further prototyping efforts. We used a combination of the tools at the Idea Forge shop, including band saws, TIG welders, and "at-home" methods including an angle grinder and a MIG welder. By using 2 long individual sections of tubing and modifying existing fabricated parts, we were able to save costs and time in this critical stage. The former pretotype tubing was modified and used to simulate the thumb guard, as well as used for the taper angle tests since it was easier to get in the ground. The 2-inch prototype was made initially to simulate the ergonomics and ease of insertion for the 2" tubing, then was improved for an attempt at feasibility testing.
Prototype #1: Thumb Guard Effectiveness
The existing pretotype was modified by cutting off the existing removal members and moving them to the top for thumb protection. This prototype tells us whether adding a thumb guard is a useful and desired feature by our users. Specifically, performing tests on both left-handed and right-handed users to make sure the modified design for storage does not sacrifice protection for either group.
Prototype #2: Stake Point Optimal Design
This is again utilizing the existing pretotype, with the thumb guards to protect the sensor. Using PLA, 3D printed stake designs that were swapped out between tests, this prototype determines our final stake design based on the ease of insertion for users. This is accomplished using the Sparkfun Artemis sensor to gather data on the force required to get the stake in the ground while also acquiring user feedback on what feels the best to use.
Prototype #3: Ergonomics/Viability of 2" Tubing
This tubing was cut and welded together based on initial calculations for supporting 6,000 lbs at the eyebolt location. We assumed that only providing a ground stop for the member was necessary for this specific test. This prototype gauges the ergonomics and comfort using the product as well as how easy the larger tubing is to hammer in for users. This directly informs us of future prototype design and questions that need to be asked.
Prototype #4: Adjustments and Feasibility Testing
The fourth prototype addresses the user feedback collected from the first three prototypes. This version incorporates the 78° taper angle stake and reinforced strike plate. It also includes a structural frame member to meet our load requirement. This prototype tests the ease of insertion with added support features and allows us to examine stake stability when placed fully into the ground.
Prototype Testing Round 1
Prototype Testing Round 1
Users were encouraged stake the prototype winch stake into the ground using three different tapers of stake tips for this testing. An Sparkfun Artemis sensor was mounted on the stake to provide real time data of the uniaxial forces imposed on the stake by each user. Unfortunately, the Artemis was unable to withstand the heavy shocks induced by hammering and ejected the memory card while testing as a result. This resulted in an inability for the device to record useful data. After each test trial, users offered their perspective on the task difficulty.
Additionally, users were asked about the thumb protection during testing.
Users were asked to insert the 2-inch tubing into the ground to test ergonomics of the winch stake.
During test trials of the final prototype, the stake tip broke off in the ground, and our team was unable to penetrate the ground deep enough to apply loading with a vehicle. Our team discovered that the prototype was significantly easier to drive in to softer ground.
Insights
Insights
Ergonomics
•Users had no concerns for hand safety
•One user reported that the higher positioning of the thumb guard improved handling
•Left handed user was able to readjust to a comfortable position easily
•Users reported that the 2” tube prototype was harder to handle and orient than the first version
•Top of stake (Impact Zone) at risk of deformation – Requires additional reinforcement
Ease of Insertion
•Users preferred the 78° taper angle stake (hard compacted ground)
•One user suggested including a bubble level to visually orient the stake during insertion
•Although more robust, the 2” tube prototype was noticeably more difficult for users to insert
Key Takeaways
Key Takeaways
Top of stake deformed when hammered repeatedly
Thumb protection is functional for all users
78° taper angle is better than 66°
82° taper angle was too fragile and blunted/broke
Difficult to drive into hard ground (1.25-inch tubing was tough, 2-inch tubing was nearly impossible)
With reinforced striking plate, 2-inch tubing was slightly easier to drive in, but the tip broke off
PETG cannot withstand repeated tests
Moving forward, we need to optimize the ergonomics with the expected strength of our design. We may also reconsider the loading constraints for current calculations or scale down future prototypes for cost/portability purposes. Additionally, we will reinforce the top with a robust plate to withstand continuous testing and try to maintain a ~78° driving angle for user comfort.
![Confidence [1]](https://lh3.googleusercontent.com/sitesv/AA5AbUD12S2Yd-nvboG-mXBsIi2PeKlTHLBkQSOTjya4ntM481awsPHV-R6E9-gGecE90XpTpmlya7aj_7q8gC4tO6p1qDuMamuIYKeZ5ZgcnegVOZxbOsh3sgCwYi5LUNDvitli__WCXX8NnGFEtmOiAwYXsUdo1rxeO3-UJYYzTCjEBS0gdulxDaFJ5SSfTsKN9sectqL4SOCw4FXKv324qHiC9s7Lmb5QDII9MDwVnDw=w1280)
Key Performance Indicators
Key Performance Indicators
70% of subjects reply with "Increased confidence" of self-rescue on post user-clinic survey
Product is targeted to self-rescue market and we want to make sure it will actually impact users positively
Tradeoff: Ease of handling
We think users will feel confident in the product if it can be tested and verified
Photo Reference [1]
70% of subjects reply with 5/10 comfortability getting it in and out of the ground or better
We want users to feel like this is an easy product to use and if they struggle to get it in the ground and handle it, it is mostly useless
Tradeoff: Strength and durability
We are struggling with this product fit and trying to optimize for it
Photo Reference [2]
80% of subjects rate it at 6/10 exertion or less
This is a more specific indicator of how comfortable they feel using the product and we plan to have a scale from 0 (driving out of it) to 10 (burying a tire and winching off of it)
Tradeoff: Reliability of staying in the ground
We are struggling with this product fit as well because the tubing design that stays in the ground is really hard to drive in
Photo Reference [3]
80% of subjects rate it as 6/10 or better on a visually pleasing/aesthetic scale
Offroaders care about the "cool factor" of products and we want to gauge how users feel about the look of the design
Tradeoff: Cost, storage
Users liked the red stake tip of our 2" prototype and this gave us an idea of where to go for the final aesthetics
Photo Reference [4]
100% of users can store the product in or on the vehicle
We want to ensure that the product is actually taken with users on normal offroad outings in case they need it. By asking directly to our users if they would have a place to store the product, we'll learn any changes we need to make
Tradeoff: Strength, aesthetics
Currently all of our users would store this product in their vehicles from interviews
Photo Reference [5]
Final Iterated Prototype
Final Iterated Prototype
Changes Implemented
Changes Implemented
Based on the user feedback and pretotypes showing that 1.25" tubing would be sufficient, the team optimized the comfort and ergonomics with the strength and sturdiness for the final design. Additionally, the red color was integrated, an anvil was added in, and grip tape was added in two places based on how users liked to handle the product.
The final features are:
Large eyebolt to handle up to 6000lbs safely from a winch
Thumb guards
Anvil to hammer on
Bracing member that acts as a ground stop
Compact storage capabilities
Lightweight (15lbs)
Grip tape for comfort
Final User Testing
Final User Testing
User Feedback:
Grip desired on angled bracing for users that want to kneel - integrated
Can be loud (not a priority, could be an advantage to draw attention)
100% KPI alignment from user clinic
User Clinic
User Clinic
The user clinic was designed to put users in different environments that they might use the winch stake in by using three different types of “ground” to simulate hammering it in.
Users were given a 2lb Brass hammer and instructed to do whatever felt most intuitive to them to get it in each bucket. Unfortunately, the buckets were not quite tall enough to go all the way to the brace, but it was still a useful representation of the force required from them. The three ground types were potting soil, top soil, and play sand. The ground materials were repacked between each test for consistency. We had three users come to the official user clinic, while we have had an additional three users testing the final prototype in different real world ground types. The setup in three distinct buckets is shown in the figure.
All three team members were present for the user clinic and we observed how the users were naturally interacting with the product for the first time, as well as any emotions we could notice during the testing.
Since this was conducted on campus on expo day in bad weather, user accessibility was limited. User 1 was a random sample who offroads and agreed to take the time for the test, but other random samples were in a rush or hestitant to agree. This resulted in two classmates, both of which offroad, being clinic participants.
User behavior was recorded and they were asked a post-clinic questionnaire to rate their perception of our KPI’s on a scale out of 10. These questions are included below in an Appendix section.
Overall, the users showed a resounding success of our KPI’s summarized in the table. This reinforced that our product is satisfying our users needs and expectations from us. Users did mention that it was loud to hammer it in, but it is more muted in real ground and we have concluded that if you need to use the product to rescue yourself, the noise would be less of a concern and actually might function to draw attention to the user in an emergency.
Next Steps
Next Steps
We have a great medium-fidelity prototype!
Need to:
Raise funding
Make final technology improvements to stake mechanism (soil stability)
Destructive testing
References
[1] https://www.pexels.com/photo/woman-wearing-blue-shawl-lapel-suit-jacket-1036622/
[2] https://www.istockphoto.com/photo/relaxation-at-home-gm1834965956-551029885
[3] https://stockcake.com/i/intense-laboring-man_1315333_251321
[4] https://www.istockphoto.com/photo/art-museum-gm1218961153-356386069
Appendix
User Clinic
· Instructions to users:
o Please hammer this into each type of ground and remark on how easy or difficult it is for you
· Questions for users:
o Please rate the following
§ Confidence with and without the product of self-rescue (increased or decreased)
§ Comfortability using the product (mildly, moderately, not)
§ Exertion level from 1-10 with 0 being not leaving the car and 10 being burying a tire to winch off of it
§ Visually pleasing from 1-10
§ Would you be able to store this product in or on your vehicle?
o Is there anything outside of the difficulty in inserting that would make this product better for you?
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