Rice University students are working toward a long-standing goal of making the benefits of hippotherapy – equine-assisted therapy – available to those without access to a real horse.
The students' robotic device adds levels of sophistication to the project started several years ago. Their steed, named Stewie, is more comfortable and they believe more controllable for riders with neurological or movement disorders or problems with balance who could gain physical and mental benefits.
Senior mechanical engineering majors Kelsi Wicker, Sebastian Jia, Matthew O'Gorman, James Phillips, Wesley Yee and Jijie Zhou took on the challenge as their capstone project, required of most Rice engineering students.
Hippotherapy is thought to help patients with coordination, balance and posture through rhythmic, three-dimensional movement, and there are ranches around the country that cater to patients, Wicker said. "Often, it's simply an aid to put a patient in a relaxed state to do other therapies," she said.
Stewie is based on a robotic concept invented in the 1950s called the Stewart platform, which in this case uses six computer-controlled motors attached to aluminum legs that give the saddle's movement six degrees of freedom – latitude, longitude, vertical, pitch, roll and yaw.
"It's similar to what you would see on flight simulators at NASA," Yee said.
The precision motors can be manipulated by the computer in any combination at any time. That allowed the team to fine-tune the saddle's movements to match those of actual horses. Members worked with the Panther Creek Inspiration Ranch, a nonprofit facility in Spring, Texas, that offers equine-assisted therapy to those who need it.
"When we started, we were rigging this whole complicated accelerometer thing," Wicker said. "Then a professor came by and said, 'Hey, you have an accelerometer on your phone, right?'"
Ultimately, the students used a $1 app that collected the necessary data. "We taped the phone to the back of a saddle on a horse, and they took the horse around," she said. "We were able to take all of the data at the same time."
They brought that data back to Rice's Oshman Engineering Design Kitchen, where they incorporated it into their code and loaded it into a small control panel patients and their therapists could use to select a horse and control the length of a session.
Appropriately, each programmed "horse" is named for the real model at the ranch; Sayed was loaded in first, with two more to follow. "Because the app was on my phone, I had to go out to the horse ranch every time. It was really hard for me to go out and pet all the horses," Wicker said, smiling.
Stewie is designed to support up to a 250-pound rider, O'Gorman said. "We have a factor of safety of 2," he said. "It could theoretically hold up to 500 pounds, but we want to be sure it doesn't break later on." They've designed an additional saddle pad to help accommodate riders with different physiques.