2016 Technology Challenge Report

Academy of Arts, Careers, & Technology

NASA Rover Team

University of Nevada Advisors: Dan Ruby

AACT Faculty Advisors: Greg Burge, Jim Cooney, Addison Wilhite

Tech. Design, Safety, and Media: Natalie Fox, Emily Contreras-Johnson, Kimberly Aguilar, Katrina Dutt, Lori Berg, Shannon Palmer, Irene De Haan

CAD Team: Preston Latham, Dexter Bush, Owen Schenk

Fabrication Team: Dexter Bush, Travis Troop, Patrick Thompson, Kraigon Ladner, Preston Latham, Christian Oaks, Gregg Symonds, Natalie Fox, Alissa Chavalithumrong, Jordan Buxton, James Harney, Miranda Weinert, Cory Starks, Irene De Haan, Grace Wallace, Anthony Sombatoiri, Kimberly Aguilar, Sarahann Wallace, Katrina Dutt, Turbo Sombatsiri, Lorenzo Arvisu, Henry Day

Away Team:  Dexter Bush, Madelyn Newcombe, Owen Schenk, Christian Oaks, Irene De Haan, Natalie Fox

3       Technology Challenge

3.1      This Year’s Challenge

3.1.1    Technology Challenge Definition

The engineering designs from NASA are mainly focused on plans to explore planets, moons, asteroids and comets.  Designing, constructing, and testing mobility technologies to perform in different obstacle courses are the main focuses for the NASA Human Exploration Challenge.  Each rover must be human powered and be driven by two students, one male and one female.  Each year there is a different challenge provided by NASA for the teams to solve. 

3.1.2    2016 Challenges

The challenge for the year of 2016 consists of each rover being human powered, building a custom wheel for the rover, and changing a minimum of 50 percent of the combined total structure and systems.

Each team must design and build their own wheels.  The only commercial items that can be used in the fabrication of this rover are the hubs containing bearings or bushings. The wheels should include the outer surface and a supporting structure.

There also must be change of a minimum of 50 percent of the combined total structure and systems if the rover is being reused.  A reused vehicle is considered a vehicle that has been registered in competitions and participated in a race in previous years.  Adding new content or changing existing pieces qualify as a change.

3.2      AACT Rover Team Solutions

The AACT Rover Team addressed these challenges by designing and fabricating a new wheel and changing a minimum of 50% of the rover.

As a team, we have decided to come up with a new wheel design.  This year, we decided to machine our own hub along with a new tread and supporting structure.

For the minimum change of 50 percent, the AACT Rover Team has determined to completely redesign and fabricate new wheels, crew restraints, storage systems, and vehicle braking.

3.2.1    Wheel Design

For the 2016 NASA Human Exploration Challenge, the team has decided to completely redesign and fabricate new wheels.  The design process began with our students Dexter Bush, Owen Schenk, and Preston Latham trying to come up with a lighter wheel design that included a machined hub.  They had to redo the original drawing eight times in order to get it perfect.  It was agreed upon that the ninth design was the best option, which included the dimple die idea.  It was decided that the best material for the wheel to be made out of was aluminum because it would make the wheel much lighter than previous years’ designs.  This year’s wheels will be made out of 1/8” aluminum, which makes the overall weight of each of the wheels 5 pounds lighter than last year’s design.

3.2.2    Building the Wheel

To build this wheel, the AACT Rover build team began by cutting the 1/8” aluminum into 2ft by 2ft squares. They put these squares into the plasma cutter to cut the holes for the dimple dyes and proceeded to dimple die these holes. The team then bolted these to the jig and cut the outsides.  They used the CNC machine to make the hubs and installed pins onto the hubs.  Then, the team bent the L angle into a circle to create the rims, plasma cut and rolled the outside strip.  The team proceeded to assemble the wheels and welded the parts together using the tig machines. The team cut and drilled the suction hose and installed these tubes onto the cabling on the wheels.  The final step in this process was to rivet down the tread material. 

3.2.3    Returning Vehicle Requirements

The 2016 NASA Human Exploration Challenge requires each returning rover to have at minimum a 50% change.   The AACT Rover team addressed this challenge by changing the wheels, crew restraints, storage and deployment systems, and vehicle braking.

The newly designed and fabricated wheel counts as a 10 percent change for each wheel.  In total, we have 4 new wheels, which qualify as a 40 percent change.

The next part that the team changed is the crew restraints. The team determined to change these restraints to ensure the safety of our drivers. This counts as a 10 percent change.

3.3      Machining the Hubs

3.3.1    Deciding to Machine Our Own Hubs

For the 2016 Rover Challenge, it was optional to create your own hubs; however the AACT Rover team decided to take on this challenge.  Our team concluded that this was the best solution because we could not attach them to our old Chub Hub.  We would have had to use bolts to connect these parts together, but we concluded that it would be best to machine the hubs so that we could weld directly onto them.

3.3.2    Creating the Hubs      

The process of fabricating these hubs was not too difficult; however, it was time consuming.  The team began by using the CNC lathe to machine the aluminum.  This created the inside and outside diameters.  They then used the CNC mill to make pinholes and tap them.  The team finished the hubs by using the opposite side end mill to machine the swirl pattern.

 

AACT Fabricated Hubs

3.4      Precautions and Durability

3.4.1    Problems We Encountered and Our Solutions

There were a few design issues that we encountered while we worked on this project. One of the main design flaws we had was when the spokes were welded, they warped and got out of true.  To solve this problem, we welded them in a truing stand.  Another problem that the team encountered was when we dimpled the spokes, the plate warped six (6) inches.  Our solution was to build a custom steel jig, bolted it down, and then cut around the jig. The final major problem we came across was the tubing.  For the 2016 year, the team decided to use a cable to keep the tubing in place, rather than last year’s rivets. In order to keep this tubing in place, the team needed to create cable guides to keep the tubes in place.

3.4.2    Design Features That Ensure Success in the Race

The main design feature that was created to ensure success in the race was the dimple dyes. The spokes were dimple dyed to add strength. They add sideways, up, and down strength.  Another design feature that was created to ensure success were the tubes. The tubes provide suspension for our rover as it rolls over obstacles.

Dimple Dying the Wheels

3.4.3    Most Likely to Break

Early prototype testing revealed that the part that is most likely to break on our 2016 rover are the tubes. If one of the tubes break, all of the tubes could break.  We tried to prepare for this problem by creating a cable system to hold them in place.  In order to keep the cables in place, we made tabs on the side of the rims to ensure that the tubing and cables would stay in place.

Cable Alignment Tabs

3.4.4    Precautions

The 2016 AACT Rover team took a few precautions with our vehicle.  One precaution that we decided to take is that we made one area thicker where it will be welded.  This made it stronger so that it would not warp during the welding process. 

Another precaution the team took was to create a large surface area to ensure the strength and durability of the wheel.  We discovered that if there was too much tension on the wheels, they could bend.  With the larger surface area, the wheels will be less likely to bend.

Close Up of the AACT Rover Wheel Design

3.4.5    Making the Rover Lighter

We decided to make the rover lighter by eliminating large amounts of weight from the wheels.  We realized that the wheels would be the best place to take weight from due to the difficulty in pedaling in previous years.  The wheels in previous years were wider and created more friction.

To make the wheels lighter, the team used much less hardware.  We welded the wheel together rather than bolting it together as we have in previous years.  The team also used the cable tensioning method, which takes one cable through all hoses with a turnbuckle for tensioning.  This allowed us to remove the heavy rubber belting that took up space.  In total, each of our wheels were 20 pounds lighter than in 2015.

AACT Rover Wheel

3.5      Costs and Materials

 Materials paid for by Nevada Space Grant Consortium (NSCG) and Washoe County School District (WCSD)

Cost	Material	Amount for Set	Paid By
$47	1/8” Plastic Covered Stainless Steel	100’	NSCG
$26.20	1/4” Eyelet Turnbuckle	5	NSCG
$19.97	Swaging Tool	1	WCSD
$14.8	1/8” Aluminum Ferrule and Stop Set	10	WCSD
$8	SWM Bolts	1 pack	NSCG
$250	Sprocket	10	NSCG
$10	Cable Noodles	10	NSCG

3.6      Locations

For this challenge, the AACT Rover Team used a few locations to construct our rover.  We mainly used the Truckee Meadows Community College’s campus for our meetings.  We used this campus’ workshop to build, machine, and weld our rover.  We also used the Academy of Arts, Careers, and Technology’s campus, located across the street from TMCC, to use the computers for writing and drafting.  We also used AACT’s bike shop and parking lot to train our athletes.

3.7      Lessons Learned

During the process of building this NASA Rover, our team learned many valuable life lessons.  We learned the value of time management through real-life deadlines.  We learned how to accomplish tasks without having to stress over the time.  Another lesson that we learned during this challenge was how to work together as a team.  Each team member had to communicate with each other in order to create this rover, which required patience and listening abilities.  Every one of us had our own ideas on how we should create this rover and we all needed to work together to create one functioning rover.

The most important lesson we learned was how to function as not only a team, but a family. We learned how to treat everyone with equal respect.  This challenge taught us how to function as an engineering team in ways that we had not done previously to ensure a working rover.

2016 AACT Rover Team