Engineers to help paraplegic student walk at graduation
When graduating senior Austin Whitney hears his name called this Saturday at the University of California, Berkeley’s Commencement 2011, he will rise out of his wheelchair, walk to Chancellor Robert Birgeneau and shake his hand.
That moment will cap a long and dramatic journey for Whitney, who was instantly paralyzed in 2007 when a car accident severed his spinal cord. In the four years that passed, life lessons were learned, Whitney’s spirit rebounded, and technological advances were explored. Last year, Whitney began working with a team of UC Berkeley engineers developing exoskeletons, wearable robotics that look like souped-up leg braces, and found himself imagining the unimaginable – a graduation walk.
“Ask anybody in a wheelchair; ask what it would mean to once again stand and shake someone’s hand while facing them at eye level,” said Whitney, 22, a double major in history and political science. “It will be surreal, like a dream.”
Making that dream happen has humanized the exoskeleton project for Homayoon Kazerooni, professor of mechanical engineering, and his team of UC Berkeley graduate students, so much so that they named it “Austin” in honor of its first human test pilot.
Core members of the team include Michael McKinley, Jason Reid, Wayne Tung and Minerva Pillai, all Ph.D. students in Kazerooni’s Robotics and Human Engineering Laboratory. They have worked around the clock for the past year – and especially for the past few months – in preparation for commencement, an annual event that honors all graduating seniors.
“In the beginning, we hadn’t realized how important Austin’s role would be,” said Reid. “The feedback he provides – from the comfort level of straps to the ease of control – has really helped us fine tune the design of this machine.”
A life-changing injury
Austin Whitney grew up in San Juan Capistrano in Southern California. He was involved in student government and theater, played sports, and excelled in academics, graduating in 2007 with a 4.0 GPA. He also was not immune to the feelings of invincibility so characteristic of youth. After drinking with friends on a summer day in July 2007, Whitney got behind the wheel of a car and crashed into a tree.
His spinal cord was severed just above the hip. He was hospitalized for 41 days and embarked on a tough physical and psychological recovery, but he refused to let the accident detour his plans for college.
Wasting no time, he started attending college classes 10 days after being released from the hospital. He attended UC Santa Barbara before transferring to UC Berkeley as a sophomore. Nearly four years after his accident, Whitney is about to finish his undergraduate studies.
The Austin project represents the latest in a series of exoskeletons Kazerooni and his team have developed over the past decade. Kazerooni’s work in this field began in earnest in 2000 with a Defense Advanced Research Projects Agency-funded project to create a device that can help users carry heavier loads for longer periods of time. That project led to the Berkeley Lower Extremity Exoskeleton (BLEEX), a machine unveiled in 2004. At that time, Kazerooni also realized the potential use for exoskeletons in the medical field, particularly for physical rehabilitation and as an alternative to wheelchairs.
Aided by increasingly powerful batteries and faster computer processors, among other advances, there has been significant progress made in recent years in exoskeleton research, not just by Kazerooni and Berkeley Bionics, the company he co-founded in 2005, but by research teams around the world.
In 2009, Kazerooni and his team jointly developed with Berkeley Bionics the Human Universal Load Carrier (HULC), a successor to BLEEX. Last year, Berkeley Bionics also successfully launched an exoskeleton for paraplegics called eLegs. Another exoskeleton by Israeli company Argo Medical Technologies was even featured in an episode of the TV show “Glee.”
“What distinguishes the Austin exoskeleton from the others out there is its simplicity for unsupervised in-home use and its lower cost,” said Kazerooni. “We made the conscious decision to only focus on key functions to keep the cost down. Users won’t be able to walk backward or climb ladders with the Austin exoskeleton, but what we sacrifice in capability, we gain in accessibility and affordability. Just getting people to be upright and take steps forward is already a huge advance in increasing independence.”
Kazerooni noted that current exoskeletons on the market run about $100,000 and up. Developing more affordable exoskeletons will bring this technology to a larger group of people, he said.
“The streamlined Austin exoskeleton is still in the early stages of research and is not yet connected to a company for development, but I do not see any real obstacle to bringing Austin exoskeletons to market at a price comparable to some motorized wheelchairs,” said Kazerooni.
Keeping it simple
The challenge, the researchers said, is to resist the temptation to over-engineer the machine. Rather than rely upon a large number of hardware components, they favored computation and elegant programming to perform key functions.
“It is much harder in engineering to keep things simple,” said Tung. “It’s easy to just add more parts to do what you need, but that raises the cost of production, and it means more things can go wrong.”
McKinley added that this streamlined approach has more than a cost-benefit to the end user. “With fewer components, we can make the exoskeletons resulting from the Austin project easier to use, operate and maintain,” he said. “Our goal was to create a workhorse device able to faithfully handle the most essential tasks of daily life.”
Robotic exoskeletons generally share similar elements: mechanical braces that can be strapped onto the user’s legs and body, motorized joints controlled by actuators, electronic sensors, a computer brain that orchestrates the movements, and a portable power source.
When possible, the researchers used off-the-shelf, low-power parts and adapted them to their needs. They focused their efforts on the motions considered critical for mobility: standing, walking forward, stopping and sitting down. They then developed a number of innovations, including the integration of components and having some parts perform dual functions.
“If you cut down on the number of motors, you can cut down on the number of sensors needed, which in turn simplifies the device and leads to lower cost, but this also makes the exoskeleton motion control more complicated,” said Reid. “Sophisticated motion control adds little, if anything, to the cost of production, but it requires a great deal of research and creativity at the design stage. That is what we are doing.”
The computer that sends movement instructions to the motors and gears is worn in a small backpack, which also contains a rechargeable battery that powers the Austin exoskeleton. A single charge can sustain the exoskeleton for 4-8 hours of use. While the machine helps with movement, the user is responsible for balancing, which means candidates for exoskeletons must have some upper body control to manage that task.
“People with permanent mobility disorders suffer from secondary injuries resulting from long-term wheelchair use,” said Pillai. “This technology offers an unprecedented degree of mobility and independence while decreasing the likelihood of secondary injuries.”
Giving “the gift of hope”
It may be years before the exoskeleton’s namesake will own his own personal device, but Austin Whitney’s impact on its development has, and will, be significant.
“This team is so much more than just a group of researchers. They are my best friends at the university,” said Whitney of the experience he’s had with the engineers over the past year. “The exoskeleton the world will see on Saturday will have been built with much more than just steel and circuits – it has been built with compassion and a great devotion to the idea of touching lives all around this world.”
Having quit drinking after his accident, Whitney regularly shares his story with students as an anti-drunk driving and motivational speaker, and is now considering law school. He continues to maintain an active lifestyle, helping to raise money for charities such as the Wheelchair Foundation and the Swim with Mike Foundation, which provided him with a scholarship. Whitney has also been recertified to scuba dive and is working on his scuba diving instructor certification.
And after May 14, he expects to add standing on stage before 15,000 people at Edwards Track Stadium for UC Berkeley’s commencement to his repertoire of achievements.
“This work will constitute one of the most important endeavors I will ever do in my life,” he said. “To have this knowledge of the larger picture, of the possibility that this could affect the lives of countless people around the globe, giving them the gift that I’ve been given – the gift of hope – it truly puts even our most frustrating days in perspective for me.”