About

My name is Eliot Kristan and in November of 2010 I started to design and build a lower limb exoskeleton suit for my Mom. She has Multiple Sclerosis and has limited use of her legs. I’m hoping that the end result will at least be beneficial in a therapeutic way. I also hope that others might find the information at openexo.com helpful for similar projects.

If you’d like to get in touch, you can email me at eliot dot k at gmail dot com.

6 Responses to “About”

  1. This is a very interesting and helpful project. I am also interested in making an exoskeleton and I hope you don’t mind to answer some questions of mine. How do you know how much torque is required for your exo? How to control the position of exo during walking?
    Thank you very much :)

    • Hi Pin, I apologize for the time it took to get back to you. I’d be happy to answer any questions you may have.

      That’s a good question regarding the torque. I actually haven’t done any measurements to more precisely determine the forces at play with actuating the leg joints and also keeping them rigid while dealing with the weight of the rest of the body.

      What I can tell you though is that I’m using a wiper motor which has two different power input levels (determined by a single ground connector and two different positive connectors). The high input setup facilitates faster motor speed but lower torque levels and a decreased ability to handle higher loads while the low input provides much better torque capabilities. So I opt to run the power into the low-side input. I believe that this is the nature of many wiper motors.

      I’ve been using mainly a 12 volt power supply but one with ample amperage output. I wrote moree about the batteries here: http://www.openexo.com/2011/09/new-batterie/. And when I use the device on my body applying load, the amperage draw can go up to 20-25 amps.

      I am currently controlling the position of the motors during walking by way of a rotary encoder that’s fixed around the shaft of the motor. The value of this is then translated by a board within the motor housing and then output as an analog signal to an Arduino. The analog signal represents what angle/position the motor shaft is in. There is also an analog input on the wiper motor board where I can send a PWM signal to control what speed and in what direction I want the motor shaft to spin in. I then use fuzzy logic to make the shaft do what I want to do (initiate walking movements or standing say) by managing this input and output on the motor board with the Arduino. I have the code for this (not commented very well right now but it’s on my todo list) up on GitHub here if you’re interested:

      https://github.com/eliotk/OpenExo

  2. Hi Kristan.

    I’m Bean. I’m a Vietnamese student. I and my friend are initiating a exoskeleton project. I want to build it cause it’s very very helpful, practical and novel.

    I just found your website, you update all the info and details of the project and I think this page is so great, cause exoskeletons are really rare in Vietnam, and it’s difficult to find any tutorial (even English tutorials).
    So I do appreciate what you’re doing and sharing.

    I just found your page hours ago, so I’m gonna spend 1 or 2 days to read all the articles and tutorial on the page, and then if I have any question, I hope I can post them here and you can help me somehow.

    Nice to meet you. You’re the best.
    Bean.

  3. HI Eliot Kristan,
    I am Habib Ali, a student of Biomedical Engineering, from India. I found your website very useful, and it has inspired me to make my exoskeleton open too :)
    Here is the link to my blog http://rewardexo.blogspot.in/
    and my facebook page is http://www.facebook.com/rewardexo
    Please do visit ! Your suggestions would mean a great deal to me
    Regards
    Habib Ali

  4. I really like your project. My wife has MS also. She has trouble lifting her right thigh.
    We are using a kickstart device – but it doesn’t have enough force to overcome her weakness.
    Your wiper motor is a really great idea, I am bit lost when it comes to controllers and sensors- but it is really great to see some trying to tackle this. Maybe this will give you another idea to perfect your prototype.
    http://cadencebiomedical.com

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