Jackrabbit in the Spotlight / Hatkin’s interest in linear controls lands him a Bullseye

Brady Hatkin knows his way around a hockey arena. A roping arena? That’s a different story.

But the fact that the electrical engineering major is more comfortable on ice skates than on a quarter horse didn’t keep Hatkin from being a major contributor to an award-winning project to create an autonomous team roping dummy.

The Bullseye autonomous roping dummy is a three-wheeler using a 24V battery system. Standing at around 3 feet tall and 8 feet in length, Bullseye simulates a live steer, reaching up to 22 mph and performs complex turning paths determined by the user via a handheld remote controller, allowing practice without the use of live steers.

Hatkin, originally of Mankato, Minnesota, was one of eight South Dakota State University students who selected the roping dummy for their senior design project.

Bullseye was tabbed as the top electrical engineering project at the Lohr College of Engineering’s Engineering Expo April 28. The May 9 graduate considers that one of the academic highlights of his SDSU career, especially considering the complexities of making a three-wheeler imitate a steer.

Jason Sternhagen, research associate III in the electrical engineering department, said, “Since one of Nick’s roping arenas is inside of a metal building, the traditional navigation method of using GPS won’t work. Overcoming this challenge required a tremendous team effort to develop the necessary electronics and software systems.”

Creating Bullseye became a two-year challenge

Engineering students took a stab at the project last year at the request of Nick Sternhagen, Jason’s brother and a team roping enthusiast from Yankton. Nick Sternhagen had bought a roping dummy, Sparky III, from a manufacturer that since went out of business. 

It consisted of the wheels, the head and body of the dummy steer and a back-drive motor. 

It could only travel straight and only for the amount of seconds set on the timer. If roped, it would stop. Nick Sternhagen, who ropes regularly with friends and whose daughters rope in 4-H and high school rodeo, wanted a more realistic training partner and become the project sponsor both last year and this year.

Hatkin explained that last year’s senior design team took Sparky III and “got it to a state of autonomation and remote control, but didn’t work as intended. It tried to go in the general direction, but it was all over the place. It didn’t follow a smooth path. They didn’t have the range to wirelessly communicate across the entire arena and didn’t have proportional control of the drive or the turning motors.”

The project that Hatkin and his classmates took to the expo had a range of 500 feet compared to the 150 feet they inherited. 

Proportional control added

Proportional control is a common automation feature that operates similar to a dimmer switch. In Bullseye’s case, the device is a joystick. When the operator moves the throttle up 50% of the way, that signals the motor controller to deliver 50% of the motor’s power. “Last year they just had a button for a slow mode or a fast mode,” Hatkin said.

He added, “With your turning, when you point your joystick 30 degrees to the left, the wheels should turn 30 degrees to the left. Last year they just had a turn left or right, the joystick did not command a specific turning angle.

Hatkin’s eight-student group was split into two teams with two electrical engineering majors and two computer science majors working on the controller and hardware side while an equal pairing of students worked on navigation and autonomy. Hatkin worked with the controller and hardware.

“We did a lot of research on wireless communication, figuring out how we could talk to this thing over a range of greater than 500 feet, which is primarily what we did first semester and then picking out a controller we could use to send all the inputs across. Then I started designing a printed circuit board.

“All of our inputs from the controller get sent to the printed circuit board, and that would route all signals and convert signals to different logics levels and digital vs. analog so we could communicate with all the circuitry to drive the motors,” Hatkin explained.

Hatkin tasked with printed circuit board

Hatkin said designing a complex printed circuit board was the most challenging part of the project for him.

Specifically, he cited “making sure that when I designed it, we had everything not only my team needed to control the robot, but also the navigation team had everything they needed for when they added the sensors and the ‘smarts’ was a lot of work. 

“I had to make sure everything was perfect and that  we wouldn’t have any problems so the navigation team would have as much time as they need to implement their subsystems to make it follow paths.”

The controller and hardware work was finished about six weeks before the expo with the navigation work finishing a week before the expo. Testing was done in front of Daktronics Engineering Hall, home to the McComish Department of Electrical Engineering and Computer Science, and some at the rodeo club’s campus arena.

However, no one attempted to lasso Bullseye. That was reserved for Nick Sternhagen, who picked him up May 17 and is getting it set up in his indoor arena.  

Nick Sternhagen said, “The team spent a lot of time and effort to fix issues that came up. Seeing the end results at the demo and how they integrated the hardware and software was impressive. It was very exciting to see this idea become a reality.”  

A liking for linear controls

While Bullseye was Hatkin’s first rodeo, it wasn’t his first time working with linear controls.

As part of junior class assignments, he and a partner redesigned the control system for Disney’s Hollywood Studios ride Tower of Terror, in which patrons plummet 130 feet in a randomized, accelerated elevator. The class assignment was to “ride the fine line of thrill and safety,” Hatkin said.

So, it’s not surprising that linear controls was his favorite class. “I like being able to be in control, to design something and know everything that the system is going to do. I know everything to a T. I know how it is going to react and I know how it is going to behave, to be able to see things move. It’s cool to tie the electrical and mechanical components together” in a remote and autonomous operation.

Hatkin began tutoring for the linear circuits 1 class in the spring semester of his sophomore year. A member of Eta Kappa Nu, the electrical engineering honor society, Hatkin has tutored or been the lab instructor for at least one electrical engineering class each semester through this spring, when he taught the lab for a junior-level microcontrollers class.

Life outside the lab

Despite his academic achievements, Hatkin’s friends wouldn’t call him a technogeek or a laser-focused scholar.

“It’s been easy to live a dual life — to work hard at school and still have a social life,” he said. On fall weekends he could be found on his grandfather’s land near Howard hunting pheasant or deer. During his freshman and sophomore years he was a right winger for the SDSU hockey club as well as serving as its secretary.

Hatkin was captain of the varsity hockey team at Mankato West and longed to continue to play his favorite sport after his 2022 high school graduation.

As a Jackrabbits forward, he was pulling a 3.3 to 3.5 GPA, but it was “getting hard to balance school and hockey with practice three times a week and weekend games in different states. I felt like I was falling behind and scrambling to get assignments done. My work was not to the best of my abilities.”

His grades improved to 3.8 to 4.0 in the following semesters, and he put in 40- to 50-hour weeks working on the senior design project this year.

With graduation and a celebratory trip to Florida behind him, Hatkin started his career June 1 at Myer-Hall Machine Works in Canton, a startup company that creates robotics and automation for manufacturing firms. Most of his duties will be creating custom designs so the repetitive tasks can be left to robots.

In his free time, he plans to lace up the skates again in a Sioux Falls men’s league. No word yet if Nick Sternhagen can rope him into joining him in the rodeo arena.