Icon for: Evan Chang-Siu

EVAN CHANG-SIU

University of California at Berkeley
Years in Grad School: 5
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Presentation Discussion
  • May 22, 2012 | 03:32 p.m.

    Fascinating work! I enjoyed watching your video – your explanation together with the included footage made it very clear.
    Thank you!

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    Evan Chang-Siu

    Presenter
    May 23, 2012 | 12:42 a.m.

    Thanks!

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    Haifei Cheng

    Guest
    May 23, 2012 | 12:51 a.m.

    Nice work!

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    garry siu

    Guest
    May 23, 2012 | 10:18 a.m.

    A very informative video, hopefully the active inertial sensor will lead to further developments and incorporated into terrestrial and aerial search and rescue vehicles.

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    Debra Bernstein

    Associate
    May 23, 2012 | 03:12 p.m.

    Great video! (I particularly love the shot of the lizard sitting on your robot). I’m curious about the practical applications of your work. In the video you mentioned search and rescue robots – I can see the tail being useful in those situations, although it also seems like an appendage might just get caught in debris (not sure if that’s a concern or not). Are there other ways you could see applying this type of design?

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    Evan Chang-Siu

    Presenter
    May 23, 2012 | 03:47 p.m.

    Thanks! Your insight is correct, and I totally agree that the cons of having a tail could be that it gets caught on debris. This would definitely be one reason to limit the length of the tail even though a longer tail would be more effective in terms of providing a great moment of inertia. However, biological systems such as lizards, cats, lemurs do have tail lengths that are up to and greater than body length and fair very well in unstructured environments. What this may call for in an engineering setting is a flexible tail design as opposed to a purely rigid one that can deform around obstacles or maybe one that detaches easily as a last resort in emergency situations. Depending on the task of the robot, it would be nice to be able to quantify how long is too long for a tail, but I think this is a very complicated problem. Other applications would definitely fall into air or space vehicles, since orientation is very important.

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    Debra Bernstein

    Associate
    May 25, 2012 | 09:51 a.m.

    Thanks, Evan, for your reply. It’s really interesting to see how you’re mapping between the biological and engineered worlds.

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    Amber Bratcher

    Trainee
    May 23, 2012 | 04:40 p.m.

    Nice work! I am also curious about the practical applications of having a tail on a robot. In terms of encountering obstacles on the ground, couldn’t instability issues be overcome by modifying the wheel or track pattern used for locomotion? I’m wondering about the costs of having a tail in terms of power requirements and additional weight, as well as the monetary costs of the additional sensors needed to manipulate the tail. Or perhaps these costs are so minimal that they are not an issue. I can definitely see the advantage to a tail when flying through the air, but I don’t know how often flying through mid air would occur for a rescue robot. Regardless, it’s really interesting work!

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    Evan Chang-Siu

    Presenter
    May 24, 2012 | 12:39 a.m.

    Thanks! I agree that modifying the mechanisms that affect ground interaction and designing intelligent strategies will definitely help with stability. However, we feel that the next generation of search and rescue robots will be designed to quickly run over unstructured terrain unlike the slow moving ones of today. You can imagine this fast running would cause many perturbations, where an active tail could quickly whip around to perform an inertial maneuver or even reach out and contact the ground to compensate.

    Experiment 3 at time 1:13 in this video shows a simple case:
    http://www.youtube.com/watch?v=s2Lk_2YCtA4

    We are very interested in (and currently exploring) how the ground interaction forces and the inertial forces can be coordinated so that in certain cases we can get improved stability (disturbance rejection) or in other cases improved maneuverability (fast turning).

    Added weight is definitely a factor, and we have shown that we can make an effective tail with motors and transmission to be less than 20% of the body, which is about the same ratio as the lizards tail to body mass ratio:

    http://ieeexplore.ieee.org/xpl/articleDetails.j...

    As for cost, inertial measurement units are becoming much cheaper and smaller these days. For example you can buy a Nintendo wii mote, which has all the necessary sensors for under 30$.

    Thanks for your thoughtful questions!

  • Icon for: Carol Johnson

    Carol Johnson

    Trainee
    May 24, 2012 | 01:46 p.m.

    Neat stuff! Sounds like it’s a lot of fun. Great presentation, very clear and easy to understand.

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    Evan Chang-Siu

    Presenter
    May 24, 2012 | 02:57 p.m.

    Thanks!

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    Christie Peters

    Guest
    May 25, 2012 | 01:39 p.m.

    Any project that can contribute to search and rescue vehicle design AND provide insight into the biomechanics of velociraptors gets my vote!

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