Student-Built Solar Electric Utility Vehicle to Compete in World Solar Challenge
Tom Lombardo posted on June 17, 2017 |
These students want to change the automotive industry by making a practical solar-electric vehicle.

This October, Iowa State University's PrISUm design team will travel to Darwin Australia, where its solar-assisted electric vehicle (SAEV), Penumbra, will compete in the 2017 Bridgestone World Solar Challenge. Formed in 1989, PrISUm has designed and built more than a dozen SAEVs and they've competed in every SunRayce, North American Solar Challenge, and American Solar Challenge. Penumbra is the team's first car to race in the World Solar Challenge, where it will compete against WSC veterans such as Stella Lux and Sunswift.

Penumbra (2017) Unveiling
Penumbra (2017) Unveiling

I recently spoke with Dylan Neal, a senior in mechanical engineering at ISU, who currently serves as PrISUM's Project Director. He was reluctant to divulge any technical details about the car since the competition is still a few months away, but he did share some insights about the team, its mission, and the design process.

The PrISUm team with its 2016 Solar Car, Phaeton 2
The PrISUm team with its 2016 Solar Car, Phaeton 2

World's First Solar Electric Utility Vehicle

PrISUm's earlier solar cars (like the Phaeton 2 shown above) were one-seat models designed specifically to compete in SAEV races. As a member of the leadership team, Dylan helped PrISUm shift the focus toward a more practical solar electric vehicle - one that could someday be manufactured and sold to the general public at a competitive price. That was the impetus to design the Penumbra, which PrISUm calls "the world's first solar electric utility vehicle."


Penumbra with ISU Mascot Cy the Cardinal
Penumbra with ISU Mascot Cy the Cardinal


The team set out to create a four-seat solar electric vehicle that can go 150 to 200 miles on a charge. For city driving - say, going to work every day - the integrated solar modules will replenish the batteries while the car is parked, making the Penumbra a net-zero energy car. For longer commutes, the batteries can be recharged at home through a plug-in outlet.


Drivers can also register their phones with the car, allowing them to customize the driving experience. When a registered phone enters the vehicle, the car greets the driver and, through its infotainment system, gives access to music, communication, and navigation systems. PrISUm partner Harman International, developer of connected products for the automotive industry, provides assistance on the infotainment system's human machine interface.

Inside the Penumbra
Inside the Penumbra


The team won't release any details about the technology, but their previous models used high-efficiency SunPower C60 monocrystalline solar cells, like the ones used on NASA's Helios solar electric airplane, so it's safe to say the same cells are used on the Penumbra. Like all EVs, Penumbra uses regenerative braking to help recharge the batteries. Carbon fiber composites give it a good strength-to-weight ratio, and additive manufacturing helps reduce waste and mass and create parts that aren't possible (or practical) with traditional machining techniques. The team is pioneering better manufacturing processes that can be used throughout the automotive industry. In many ways, the Penumbra serves as a proof of concept for both materials and methods.

Unlike most SAEVs, Penumbra has an actual rear window.
Unlike most SAEVs, Penumbra has an actual rear window.

PrISUm Team

PrISUm operates like a Silicon Valley startup company, from its youthful vision and energy to its corporate hierarchy. Young entrepreneurs often have day jobs to support themselves while they spend their free time pursuing their vision. In this case, the ISU team consists of full-time students who dedicate their non-classroom hours to the project. While the bulk of the team members come from engineering disciplines, there's no technical requirement for membership. In fact, they have a diverse workforce, consisting of mechanical, electrical, industrial, and aerospace engineering students, as well as students majoring in business, public relations, and even elementary education. (Elementary education majors? More about that later.) About 15% of the team members are women, and 40% are native Iowans. Many of the students are lifelong shade-tree mechanics, while others spent their youth in Iowa's cornfields, often repairing farm equipment. One of the project leaders built a fully-electric Jeep when he was sixteen years old.

Regardless of a newcomer's prior experience, the more seasoned team members and the faculty advisors teach technical skills to the young recruits. Students are often learning concepts in a practical application years before being introduced to the same ideas in a classroom. Teaching others and learning new material in context are two of the best educational methods for any discipline, especially engineering.


Each car that PrISUm builds takes about two years from conception to completion - one year of design and one year of manufacturing and testing. This allows a typical student to work on at least two different vehicles while attending ISU. It also provides a nice balance of experience and fresh ideas.


The multidisciplinary team includes some obvious branches of engineering - mechanical, electrical, aerospace, and industrial - as well as computer engineering (onboard infotainment system) and industrial design (interior and exterior aesthetics, human-machine interface, ergonomics, cognition). Business majors handle project management, including supply chain issues, lead times, etc. All teams maintain thorough documentation so that the next generation of PrISUm members can pick up where the previous team left off.


Each sub-team - mechanical, electrical, business, and systems integration - is assigned part of the project in a "black box" format: it needs to do X task, fit into Y area, and cost no more than Z dollars. Sub-teams have project leaders, with the systems integration group serving as the communication channel between the other sub-teams. They attend weekly design reviews and help the other groups understand where their part of the project fits into the whole and how it interfaces with the other components. In effect, the systems integration team assures that the project moves along according to the projected timeline, and recommends reallocation of resources when necessary.


Community Outreach

And what about the elementary education majors? I hate to stereotype, but in general, engineers don't always make the best communicators. PrISUm's mission is to change the automotive world, and part of that quest involves community outreach. Besides going to competitions, the team takes its vehicles on tour, introducing the public to the importance of sustainability in transportation and energy. In its effort to influence the next generation of leaders, engineers, and citizens, PrISUm frequently presents at elementary schools, hoping to inspire the next Elon Musk. Education majors translate the "geek-speak" into lessons that are appropriate for school kids. These future teachers not only learn about science and technology by working with the team, they also gain valuable experience in lesson planning and delivery. How cool is that?

Inspiring the Next Generation
Inspiring the Next Generation

Extra-Curricular Learning

In many cases, the students have to learn application-specific skills and techniques that may not be a part of the curriculum at all, so they partner with engineers from local industry, who serve as volunteer consultants. For example, when they decided to use a carbon fiber monocoque structure, there was nobody on campus with that expertise and no laboratory in which to experiment and build the structure. Industry partners gladly provided advice and facilities, allowing the team to create something that virtually nobody in the automotive industry was making.


Students will also talk to automotive technicians to be sure the parts are easy to access for repairs and they consult with machinists to ensure design-for-manufacturability. Several ISU faculty members are registered Professional Engineers; they sign off on all designs in their respective areas. When an on-campus PE is not available in a particular discipline, the team relies on PEs from their industrial partners.



To the Future

"We want to be the step from the now to the future." - Dylan Neal, PrISUM Project Leader

Every morning, I get up, read the news, and become thoroughly depressed about what's going on in the world. But now and then I meet students like Dylan - sometimes in my own classroom and other times through my research and writing - and hear about the amazing ideas they have and the tireless efforts that they put forth to make the world a better place. These students, along with their faculty mentors and industry partners, remind me that there's hope for the future.



If you'd like to support team PrISUm, click here


Images courtesy of PrISUm



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