UMD students build 'robotic pack mule'

A group of University of Minnesota Duluth engineering students has spent two semesters designing, building and refining a "robotic pack mule" that could be used by the military.

Colby Carlson rides atop a prototype robotic pack mule on the UMD campus Friday while Josh Duellman runs alongside with the robot’s controller. UMD mechanical and electrical engineering students developed the robot for the Air Force Research Laboratory Challenge. Steve Kuchera /

A group of University of Minnesota Duluth engineering students has spent two semesters designing, building and refining a "robotic pack mule" that could be used by the military.

On Tuesday, they'll see if it carries its weight against creations from other schools around the country.

The group of 14 UMD seniors, all majoring in mechanical or electrical engineering, will be competing at the Air Force Research Laboratory Challenge at Arnold Air Force Base in Tennessee. The project is the capstone project for the students, who all will graduate this May.

Dr. Emmanuel Enemuoh, associate professor of mechanical engineering at UMD, said that being selected is quite an honor.

"We are very lucky to be a part of it," said Enemuoh, who teaches the capstone class. "It is usually just Ivy League and military schools - top schools we will be competing with."


The process began more than seven months ago, he explained, when the students received the challenge from the AFRL and submitted their proposal. Acceptance of that proposal came with a $20,000 grant to work on the project. The challenge was to design and build a resupply device; the team was tasked with making it operational either manually or autonomously, and able to tackle rough terrain.

The students met the challenge - and on Friday they showed off their creation behind Malosky Stadium at UMD before heading to Tennessee.

Colby Carlson holds his hands up to demonstrate that he’s not controlling the robotic pack mule. Steve Kuchera / DNT

The pack mule, which resembles an ATV with no seat or controls, is capable of hauling loads of up to 350 pounds at speeds up to 15 mph.

Garrett Drechsler, a mechanical engineering student, said that the process was time-consuming but worth it.

"It's no stretch to say we have all worked 40-plus hours a week on this," Garrett said, noting that's in addition to his normal workload as a student. "For the most part it is definitely where we want to be."

Drechsler did say there may be some fine-tuning of coding, but he said they're competition-ready - and ready to bring the $100,000 top prize home to UMD.


The prize, awarded to the winner of the competition, would be used to further develop and improve the robot - focused on strengthening it as well as making it lighter.

The pack mule is made of an aluminum frame and parts from a couple of four-wheelers, and is powered by a Tesla battery. It is made to be controlled manually with a repurposed Xbox controller, or autonomously by following a person wearing a remote sensor.

Zack Ludwig, also a mechanical engineering student and team leader for the project, said the fact that he and his fellow team members grew up around four-wheelers and snowmobiles was an advantage.

"That is one of our main selling points," he explained. "We did subject-matter expert interviews, where we called some airmen and pararescuemen and talked to them, and they loved the idea that it looked and drove like a four-wheeler because that's what they are used to."

Ludwig also mentioned that the pack mule could be used for a variety of jobs, from Air Force applications to humanitarian missions; he even saw a future where it could be used by private individuals to haul items on their own land.

"Maybe put some sides on the top," he said. "Have a way to slide stuff on that wouldn't come off."

The Xbox controller used to drive the robot was the brainchild of electrical engineering student Logan Lauder. He said they wanted something simple and familiar, that anyone could operate.

"We decided to use the Xbox controller because it has a lot of user inputs and they are easy to use, and intuitive," he said. "We tried to design it so it played like an RC car or video game, so people could pick it up and and start driving it."


Lauder said he thinks the autonomous controls are what will make UMD stand out at Tuesday's competition.

"(It's) the big one we tried to implement for the wow factor," he said. "Someone carrying this device (a sensor) should be able to walk along and have it follow them. So it will be a hands-free, put-it-on-and-forget-about-it kind of deal."

The prospect of a win, and the next senior class continuing work on the project for possible production, is exciting for the team - even though they'll be graduating.

"It would be such a big thing for the school," Drechsler said - noting that it's not a bad item to include on a resume, either.

UMD mechanical and electrical engineering students check over their robotic pack mule between test runs on campus Friday. Steve Kuchera /

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