Inside and outside

Ravi Balasubramanian podcast picture.


In this week's episode, we feature two stories from the Oregon State Robotics Group.

Ravi Balasubramanian, mechanical engineering assistant professor, is designing robo-inspired implantable mechanisms to improve orthopedic surgeries of all types--with a specific focus on tendon transfer surgery related to restoring function of the hand. We talk with him in part 1. 

In part 2, we explore Project Chiron, a kit that turns a mechanized wheelchair into a self-driving wheelchair to help those with ALS. It's being developed by Bill Smart, mechanical engineering associate professor, and his graduate student Benjamin Narin.

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BALASUBRAMANIAN: We are combining the human body with engineered artificial materials and by that process we are working on hybridizing the human body. 

[MUSIC: The Ether Bunny , Eyes Closed Audio, used with permissions of a   Creative Commons Attribution License  ]

NARRATOR: From the College of Engineering at Oregon State University, this is Engineering out Loud.

ODEGAARD: I’m Jens Odegaard, and today I’m talking with faculty and graduate students from the Robotics graduate program at Oregon State University.

Though that opening clip might make it sound like they're building the latest version of the Terminator here at Oregon State, the reality couldn’t be much more practical or impactful

In part one of the episode we’ll hear more from Assistant Professor Ravi Balasubramanian, who you heard at the top of the show. With his collaborators, he’s developing robo-inspired implants to help improve hand and foot function after orthopedic surgeries.

In part two, we glide on over to chat with Associate Professor Bill Smart and graduate student Benjamin Narin. They are developing a kit to turn a motorized wheelchair into a self-driving wheelchair.

Together, they are all helping make the tasks of everyday life easier for those who’ve been injured or disabled.

[MUSIC: Rubber Robot, Podington Bear, used with permission of a Creative Commons Attribution-Noncommercial License]

ODEGAARD: Now back to Ravi.

BALASUBRAMANIAN: I'm Ravi Balasubramanian, I'm an assistant professor in mechanical engineering at OSU, I specialize in robotics and biomechanics. I particularly focus on studying the movement of robots and controlling the movement of robots to do different things, such as grasping and manipulating objects. At the same time, I also study the movement of peoplehow they move their arms and hands and legs, and so that led me into biomechanics and now I'm trying to blend the two, studying both robots and the movement of people.

The idea is human inspiration to improve robot performance. So we look at how people use their hands in manipulating everyday objects, and use that to improve the performance of robotic grasping and manipulation--how will we get robots to do the same thing? Simultaneously I'm doing what I believe is very unique to my lab, which is robo-inspiration to improve quality of life for people in how they're moving their joints and their hands.

ODEGAARD: It’s this robo-inspiration that sets Ravi’s work apart. It’s unique enough in fact that he was just recently awarded a National Science Foundation CAREER Grant for the project we’re looking at today.

Ravi’s taking his knowledge of the mechanisms used to make robots move their hands and applying that to orthopedic surgery. 

We’re specifically talking about surgery for restoring finger function to a patient afflicted with median ulnar nerve palsy. Ravi explains…

BALASUBRAMANIAN: So palsy basically refers to a partial paralysis. The median ulnar nerve palsy refers to the median and ulnar nerve in your hands not being operational. What that means is that there are about 30 muscles in your forearm and hand, they are innervated by three nerves: the radial nerve, the median nerve, and the ulnar nerve. If you lose the median and ulnar nerve, you lose about 20 muscles. So that can be devastating for your hand use. So we are focusing on that particular condition where the ulnar and median nerve are not functional and that leads to inability to flex your fingers. 

ODEGAARD: In other words, damage to these is devastating. For just one example, picture Katniss Everdeen in the Hunger Games as she makes the three-finger salute by touching her thumb to the tip of her pinky finger. With median nerve palsy, that motion of the thumb can be impossible.  Now imagine how many other tasks you do on a daily basis that require that same basic range of motion.

Median and ulnar nerves can be damaged by things like wrist fractures, deep gashing wounds to the hand or forearm, or even a stroke.

For patients who don’t recover nerve function after an injury, surgeons will perform a tendon transfer surgery to move and reattach a healthy muscle to the joint or joints affected by the injury. This bypasses the damaged tissue.

BALASUBRAMANIAN: Current orthopedic surgery uses sutures to make attachments between tendons. Sutures surprisingly have been used in surgery for 30 thousand years.

So the current orthopedic surgery for that condition is to take all the finger tendons and suture them to a wrist extensor muscle. Now, while this is simple and the person can recover finger flexion, what happens is that all the fingers are coupled--the movement of all the fingers are coupled, so they can only move together in and out, so you can wave bye-bye nicely, but actually if you want to grasp something, the fingers cannot adapt to the object shape.

[MUSIC: Rubber Robot, Podington Bear, used with permission of a Creative Commons Attribution-Noncommercial License]

ODEGAARD: To get an idea of what this would be like, do an experiment for me. Move all the fingers in your hand at the same time in the same direction, at the same rate, and try to pick up or grasp something near you, a key or a pen for example. See how difficult that is? Now imagine having to live with that. Yes, the old surgery allows you to move your fingers, but their functionality decreases significantly.

BALASUBRAMANIAN: So if we can put in a simple mechanical mechanism, so without motors, no electronics, no computer signals, no battery, no power required, if you can just put in a mechanism that can scale or distribute the forces and movements better inside the body, you could get better function.

So what we are proposing is to use what is called a differential mechanism between that muscle and the tendons. So this differential mechanism allows the movement from that single muscle to be transferred to all the four tendons while allowing each tendon, finger, to close in as needed in the grasping example. In the grasping case. An example that may be easier to understand is in your car engine, in your car, there is a differential mechanism that goes between that single engine and the four wheels. The differential mechanism allows the wheels to travel at different velocities, uh speeds, so that when you take a turn in your car, the inner wheels will go slower compared to the outer wheels. Now if that differential mechanism were not there, the wheels would start slipping and that becomes dangerous to drive. We are using that same mechanical principle to improve orthopedic surgery.

ODEGAARD: The mechanism that you actually put in for this surgery, can you try and describe what that looks like for me? 

BALASUBRAMANIAN: These mechanisms would be simple levers, okay, that can move, and rotate. So imagine the muscle attached to the center of that lever and as the muscle contracts, the lever will translate.

ODEGAARD: When Ravi says translate, he’s simply referring to the movement and rotation of the levers.

BALASUBRAMANIAN: At the same time, imagine the two finger tendons attached to either side of that lever. So, as the muscle contracts the lever translates, and the two tendons will translate, and the finger will contract. Now if one finger is held down because it has already made contact with something then the lever can rotate, allowing the other finger to close in while the first finger has already made contact. Now this is what the lever will do. Without the lever, if it was only the suture, then the two tendons would be directly attached to the muscle and so you cannot have this rotational adaptation that the lever provides.

ODEGAARD: Where did the idea come from for this? It's simple in a way, yet very elegant.

BALASUBRAMANIAN: Ya, that's why I call this robo-inspiration. These same type of mechanisms have been used in the design of robot hands, so there are robot hands that where multiple fingers are driven by one motor by using these same mechanisms in between. Those robot hands have seen phenomenal success, because of their ability to be simple as well as provide the necessary grasping and manipulation function and so we are trying to bring the same thing in orthopedic surgery.

ODEGAARD: You can find pictures of the mechanism on our website:

[MUSIC: Rubber Robot, Podington Bear, used with permission of a Creative Commons Attribution-Noncommercial License]

ODEGAARD: So far, Ravi and his team of 20-25 people from backgrounds like mechanical, chemical, and biological engineering, computer science, veterinary medicine, orthopedic surgery, biomaterials, occupational therapy, and biomechanics have designed the implant mechanism using biocompatible plastics and proved the concept in human cadaver trials.

BALASUBRAMANIAN: From the cadaver study, we noticed that the fingers will be able to flex about 50% better with our implants and at the same time, use 50% less force tocreate those same grasps when compared to the current surgery that uses sutures. So that is a very phenomenal effect for a patient already who has gone through paralysis.

ODEGAARD: They’ve even tested it in live chickens.

BALASUBRAMANIAN: The chicken foot has three toes, and it turns out that the extension of the three toes of the chicken is driven by one muscle, just as in the human case after the current surgery, the finger flexion is driven by one muscle. All four fingers are driven by one muscle. So the chicken foot is an ideal example and so we are looking at that.

We have done a pilot study last quarter, in OSU we did it. This is the first time these kind of implants have ever been placed in a live creature or being. So that was really exciting for us and Jen Warnock an animal surgeon at OSU was a very, very critical person to conduct all these surgeries for us. 

ODEGAARD: The next steps are to continue testing and development with the goal of being ready for human trials in 4-5 years. Though we’ve been focused on the hand, Ravi’s robo-inspired mechanism could have a much broader impact.

BALASUBRAMANIAN: Our big picture goal is that we see an opportunity to improve functional outcomes from all orthopedic surgery. Now, we believe that instead of using sutures, we can use our implantable mechanisms to improve the function and customize the function. We believe that our work will apply to all orthopedic surgery. The two particular examples that we are initially focusing on is to restore hand function for patients who have high median ulnar nerve palsy. Another application that we are looking at is to restore the foot arch for flat feet patients.

ODEGAARD: This last detail in particular hit close to home. Here’s our audio editor Miriah Reddington jumping in as we conducted the interview.

ODEGAARD (from interview): Anything that intrigued you?

REDDINGTON: No, just the whole thing was interesting, because I was born with club feet and so I've had multiple foot surgeries.


REDDINGTON: SO I've had my Achilles tendon lengthened four different times. And like the plantar fascia released,


REDDINGTON: and it's like how would that work in like people like me? How would that help us?

BALASUBRAMANIAN:. I believe the implants we are developing for the foot problem will apply to any case where the foot arch needs to be restored back in its original state. The big picture is that we are born with limited number of muscles and limited ways in which they are routed inside our body, and if a person is already undergoing a surgery, then using these mechanisms in place of sutures provides better function and less pain in the long run. Certainly, these implants will be a great resource for those people.

[MUSIC: Rubber Robot, Podington Bear, used with permission of a Creative Commons Attribution-Noncommercial License]

ODEGAARD: We look forward to the future, when Ravi’s robo-inspired, mechanized implants could be helping everyone from our own Miriah Reddington to the more than 800,000 others who receive an orthopedic surgery each month, according to the American Academy of Orthopaedic Surgeons.

Now we shift to part 2 where we’re going to talk with Associate Professor Bill Smart and graduate student Benjamin Narin about their effort to create a self-driving wheelchair for people with a condition that afflicts one of the world’s most renowned physicists.  

[AUDIO CLIP:  from The Theory of Everything]: It’s called Motor Neuron Disease. It’s a progressive neurological disorder that destroys the cells in the brain that control essential muscle activity, such as speaking, walking, breathing, swallowing. The signals that muscles must receive in order to move are disrupted. The result is gradual muscle decay. Wasting away. Eventually the ability to control voluntary muscle movement is lost entirely.

ODEGAARD: That’s a clip from the movie The Theory of Everything where a doctor tells 21-year-old Stephen Hawking that he has Motor Neuron Disease, also known as ALS. 

SMART: So, a lot of people we work with, with ALS, they're about my age, they're married, they have kids, and then they get this horrible diagnosis. You know, I think we have the technology to make their lives better, but it's kinda selfish because, if my number comes up, I kinda want this stuff, right?

ODEGAARD: That’s associate professor Bill Smart. He codirects the Robotics Program at Oregon State. He’s answering my question about what motivated him try to tackle the self-driving wheelchair project he and his team are calling Project Chiron.

First a quick interlude about the name, because if you’re like me, you won’t be able to focus until you know why it’s called that. Here’s Bill and his grad student Benjamin Narin.

SMART: So, I'm terrible at naming projects, but my students tell me that every project should have a name, and so I said "all right, come up with a name." And it turns out Chiron is from Roman mythology, and Chiron was a centaur, so half-man, half-horse, and that seemed to fit the idea of wheelchairs. I think that's about as deep as it goes.

NARIN: So, it goes a little deeper.

SMART: Oh, it does?

NARIN: It does a go a little bit deeper. So, it's obviously a centaur. Demigod of Medicine, so it seemed like the appropriate choice, with that aspect.

ODEGAARD. Now back to the story. According to the International Alliance of ALS/MND Associations, there are “approximately 140,000 new cases diagnosed worldwide each year” mostly in the 40-70 year age range that Bill’s on the younger end of. However, like with Stephen Hawking, it can affect anyone of any age.

For those diagnosed, mobility quickly becomes an issue as muscle function disappears.

SMART: The whole idea behind the wheelchair project is we've been working with people with ALS, Lou Gehrig's Disease, for a few years and one of the things that happens with this disease is that it's progressive. You start off having some difficulty walking. You eventually progress to needing to use a wheelchair full-time. 

[MUSIC: Plastique, by Podington Bear, used with permission of a Creative Commons Attribution-Noncommercial License]

ODEGAARD: You’re probably aware that Stephen Hawking, now 75, who uses a motorized wheelchair to get around. He drives his with electrode sensors connected to this throat.

But there’s more than one way to drive a wheelchair, and that’s where Project Chiron comes in. Using the open source Robot Operating System combined with software developed for the open source robot development platform called the PR2, Bill and his team developed a kit that attaches to a motorized wheelchair. The kit’s designed to only cost about $500, so that people can buy it out of pocket without having to deal with the insurance hassle.

The kit maps a location, like your house, and then drives your wheelchair safely. Bill explains.

SMART: So one of the things we do with robots every day is tell them to go from one place to another in the lab. And they have a map of the world and they figure out the best way to go. They avoid things and I really thought there was an opportunity to take a lot of the stuff we do on robots everyday and kind of squish that technology down onto a powered wheelchair to help people maintain their quality of life. So as they're finding it harder and harder to drive these wheelchairs themselves, then maybe we can have a little bit of self-driving assistance that comes in and just make up for some of the abilities they are losing.

So the whole wheelchair project is really an attempt to take some of the research we've been doing in robotics and squish it down into this small low-cost platform that people can buy and put on their traditional wheelchairs without modifying very much.

ODEGAARD: The entire unit measures about 4 inches by 4 inches by 2 inches and basically clips on a motorized wheelchair behind the leg rest. It’s being designed to work with any motorized wheelchair so that it can be used on whatever chair a person is already comfortable with and used to using.

SMART: we've tried to make it really modular. So wheelchairs have the ability to plug in different devices. Switches activated by your head, by sipping and puffing into a breath control device, all sorts of things because disabilities are really varied. So everyone's set of abilities is different from everyone else's so we've tried to make the system quite configurable. The core of the system will take a starting point and an ending point in a map, which we've built of the world, and figure out how to go from here to there. How it gets that starting point and ending point is kind of up in the air. You could do it with a joystick. You could do it with a commercial head-tracker or eye tracker. Typically people who are full-time wheelchair users have a laptop mounted on their chair and a commercial eye tracker device on that. So they can basically use their eyes as a cursor. So all we do is we display a map in there. They select a point in the map. Click. And away they go. So we've tried to be really agnostic on the inputs, just to make it as broadly applicable as possible. 

ODEGAARD: Quick aside, when he says agnostic, he’s not opening up a debate about the existence of god, but rather using a term common in the robotics world to mean that you can use any input.    

ODEGAARD (from interview): So imagine if I had ALS, was diagnosed with ALS, I would take your system. How do I go about mapping my house or making this functional?

NARIN: Think of it almost as setting up the WiFi at your house. You don't need to know about actual networking. You just go to the address and you say I want the WiFi to be called this and you know this is the password and off and away you go. There's a router on board. You could do the exact same thing. You click, "map the house" drive around for a while. It says, "the map is now complete." You hit "okay." It loads the map.

SMART: The goal is to make it as seamless as possible, so you don't need to know robotics, you don't need to know computer science. A nice simple webpage. Nice big buttons. Three or four choices. And then ALS is as interesting condition, because you start off with a full range of abilities. So maybe we can ask you to map your house. Maybe we can ask you to do some training of the chair to show it how you drive. Then as your abilities start to decrease as you progress through the disease, we've potentially been able to build a model of how you do things. As we bring in the self-driving, we make the chair drive the way that you're used to. Or go to the places you're used to going.

ODEGAARD: So it's really tailored even to your own behavior. 

SMART: Absolutely. Because everyone is different. Everyone has their own preferences and I think to make a system like this really work, you can't have a one size fits all. It's really got to be individualized.

[MUSIC: Plastique, by Podington Bear, used with permission of a Creative Commons Attribution-Noncommercial License]

ODEGAARD: So far, Bill and Benjamin have tested the system at an ALS residence in Boston and with an individual patient in California. They’re working on dialing the system in with real people in the real world.

NARIN: What really struck me is not just what we're able to do - for me it's always been, you know, the self-driving aspect, this is really exciting, look, we can have the wheelchair drive itself. And I remember, I was down in California, and I was unpacking the system, and talking to the guy's dad, and I, one of the things I did on the step to doing full autonomy was be able to drive with an XBOX controller: it's easy, it's simple, it allows me to test some stuff. And he was really excited that you could drive it with the XBOX controller, just because the way it's currently done, there's a joystick usually mounted on the back, and usually upside down, for the caregiver and so you have to kind of go backwards and sideways. The idea that you could step away and still be able to control the wheelchair was exciting. And it hadn't even crossed my mind that this was something that was important -- I had been trying to get to this end goal -- and just seeing how this small piece made such a difference to someone, before the rest of the system was fully fleshed out, was incredible and really let me see where this could go… It seems so natural, it's incredible to be able to see what you can do, and what changes you can make in someone's life. 

ODEGAARD: This fits with the overall approach of the Oregon State Robotics Group, which we’ve heard about both with Project Chiron and at the top of the show with Ravi’s implantable mechanisms. Their informal motto is “robots for the real world.”

SMART: Both Ravi's work and our work is pointed at helping people - Ravi's in a medical situation, ours if you're a wheelchair user - but I think the thing that ties them together is focusing on the human aspects, the human interface part.

You can write as many papers as you like about robotics, but until you actually help someone in the world with a robot, then it's all very academic.

ODEGAARD: This episode was produced by me, Jens Odegaard,

[MUSIC: Plastique, by Podington Bear, used with permission of a Creative Commons Attribution-Noncommercial License]

with audio editing by Miriah Reddington. Surprisingly, funding for Project Chiron has been hard to come by, so if you’re interested in helping support this outstanding work, please contact Bill at Our intro music is The Ether Bunny by Eyes Closed Audio on Soundcloud. It is used with permission of a Creative Commons Attribution License. Other music and sound effects were used with permission of Creative Commons licenses or are in the public domain. Links can be found on our website.

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See you on the flip side.   

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