Hydraulic routing, valve mounting, hoop jumping and SWAG

Hello all!

It’s been too long since our last update, and for that we apologize. We’ve gotten a ton done. Most of it has been the not-so-glamorous support work that needs to happen. Since our last post, we’ve:

  • Acquired insurance for prototype leg and robot operations
  • Worked out a safety agreement with the Artisan’s Asylum
  • Received all of our swag!
    • 800+ T-shirts of many sizes
    • 1500+ bumper stickers
    • 1500+ wrist bands
  • Negotiated a deal with a shipping company to ship all our Kickstarter backers their rewards (without breaking the bank)

The T shirts arrived on Friday and are looking great:

So to all our Kickstarter backers, your stuff should be arriving in the next month.  It’s taken us longer than we expected, and for that we apologize.  We still need to pack and address over a thousand packages, but we have all the equipment in place to do it.

On the robot side of things we’ve also hit a few milestones.

We’ve put together a mobile, electrically powered hydraulic power unit (HPU).  This HPU will make it easy for us to do controlled, indoor testing for the prototype leg.

That cart may look familiar: we repurposed the custom-built cart we used for Gimpy, our first prototype leg.

“What did you use to power Gimpy?  Why don’t you use that to power the big prototype leg?”  Great question.  Gimpy’s hydraulic power unit could only supply 1000psi at a very low flow rate.  We need at least 2200psi to realistically test the full scale protoleg.

We’ve hydraulically plumbed the leg: all the necessary valves and hoses are in place.  The entire leg hydraulic system comes back to a pair of quick-disconnect fittings that connect to our mobile HPU.


We’ve also built up the joint controllers we’ll need to actually control this leg.  These joint controllers are much more advanced than the ones we used on Gimpy, and feature:

  • Fast Ethernet (100Mbps)
  • Power over Ethernet
  • 12-bit rotary magnetic encoder (Austria Microsystems AS5045-ASSU) for reading joint positions
  • Dual 1.5A, 12-bit, dithering current controllers for driving valves


Next up: packing and shipping over 1000 units of swag, then wiring the leg and *gasp* turning it on for the first time.

Thanks for reading and have a happy Thanksgiving holiday!




29 thoughts on “Hydraulic routing, valve mounting, hoop jumping and SWAG”

  1. Jeez guys your dragging your asses on getting our stuff to us. How about one of you act as a project manager!

    1. Dear Pissed Off Backer,

      We’re sorry the swag is late. Coordinating the manufacture and shipping of almost a thousand shirts of different sizes took more time than we thought. I know that’s not an excuse, but I just want to reassure you that there are people here, myself included, working hard to get your rewards out the door.


    2. Hi there,

      While I can understand being frustrated at later delivery than expected, I think it’s important to note that the team is still working hard on prototyping, has admitted mistakes in scheduling and apologized already up in the post, and has been truthful throughout.

      I think it’s a bit harsh that the only comment here so far is criticizing the delivery of stuff. Really, we are all supporting the development of the hexapod, and the stuff is relatively secondary as a way to say thank you. Being a small bit patient while the team works things out that they have never done before is required. 🙂

      Hope you get your rewards soon and are happy with them.

      1. Karen, your comments are right on the mark. There is nothing simple about this project as a whole, let alone the swag issue. And, as I understand it, this project is not the HEXAPOD Teams full time job. This update is a good one, and I see progress, but would like to see an update at least several times a month. We all know that the Zombie apocalypse is fast approaching and this project will be the backbone of our defense, so keeping to a schedule is key to a mission completion. And if the Zombies do not come, we will still have a HEXAPOD.

      2. Don’t feel bad, Hexapod team, this is all great experience because get to feel, first hand, how thankless engineering can be. The engineers are the ones that sweat the hardest while those that have never felt such responsibility, stress and despair are always the loudest and most demanding.

        It is just part of the package of life – ants run around building things while the outside world just sees a calm, well built structure not knowing what it took to get there.

        So, for those that are complaining about swag and T-shirts, why not go down to Radio Shack, buy some parts and build your own leg, wire it all up, program it, figure out all the endless details and then, when you have it all up working perfectly, come back here and apologize to these guys.

        Oh, don’t forget that many of the team members are also probably working full time or studying engineering full time. Both of which can drain the very life out of most people.

        Keep up the great work, team! I look forward to and appreciate every milestone and get a real kick out of watching that beast rise from your imagination.

    3. “Jeez guys your dragging your asses on getting our stuff to us. How about one of you act as a project manager!”

      Gee Pissed off backer – you need to get over yourself. Quick someone call the wwhhhaaaaaaambulance.

      Dear James & Team – thank you for continuing to keep us up to date on the status of the project. Looking forward to seeing the leg in action 🙂

  2. $75 for a couple of shirts, a wrist band and a sticker. For what I’m getting that’s a high price, and that’s not why I put funds in.

    I helped fund this to see a giant hexapod come to life.

    The shirts are merely a nice extra.

  3. Awesome progress! Don’t sweat it about the shirts. Like Riverdragon said, that’s not what we put our support into.

    Great to see that testing is about to commence! May I suggest a google hangout for backers to see her in action?

    1. Great question.

      We create motion by opening valves to allow fluid flow to the actuators. When the valves are closed, no fluid can flow, and the actuator behaves like a rigid bar.

      All of our valves have spring returns to the closed position, so when there is no electrical power available to open the valves, all actuators should behave like rigid linkages.

      So if you cut power to the robot, it should just freeze in its standing position. That said, all valves leak very slowly, so over the course of hours to days, the robot would slowly sag to the ground.


  4. Robot progress is more important than swag. Although I would like to get the wristband before the robots take over 😉

    Keep up the good work!

  5. Thank you for the update. Within the next 60 days or so I am planning on visiting your location near Boston. Could you please send me a rough work schedule of dates and times that folks will be working on the project? I would of course like to meet as many members of the Team as possible during that visit. I am somewhat flexible in my visit times.
    Keep the updates coming as you get them. Would really enjoy seeing some of the test plan for the “leg” and see how it performs against your planning data. Nothing is perfect in testing (that is why they call it a test), but performance against a planned standard is a good thing! Thank you!

  6. Can’t wait to see some videos. Real exciting project. Is the whole project being done in CAD? If so, can you also supply 3D Printed models of Stompy? Keep up the good work. I live up in NH but would be glad to come down for a “work day” to help with the shipping. Maybe others would as well especially if we could get a demo of some type or just an extra shirt?

  7. Thx for keeping us informed, even for a small time backer like myself on the otherside of US, ie Malaysia.

    Keep up the gr8 progress guys. I’m proud to play a nano part in this initiative & do look forward to the tshirt but am in no hurry. The ‘bot’ comes first. Be sure to have enough rest & keep intouch with family & friends.:)

  8. Jeez guys… clearly getting t-shirts out to people on time is, like, a million times more important than building the radest hexapod ever. gosh.

    seriously though. don’t sweat it. I’d prefer to see the leg working than get my t-shirt on time.

  9. The swag is nice, but will have far more sentimental value when the project is successful.

    Congrats on the progress, and keep up the good work!

  10. Hey guys! Great job on the swag shirts and stuff! Look really awesome! Question for you when the entire project is done, what do you suppose the time it will be finished and where will you pari it when at a supermarket? 😀

  11. Every time I read the paper about how the world has this or that major horrible thing going on, I come back and revisit the progress reports that you guys send out…and it restores my faith in the fact that great people are doing amazing things for the ultimate benefit of science and all people. Thank you, go for the gusto, STOMP ON !!!!!

  12. What flow rates (gpm) and pressures are you needing for the leg test and the final project? Are the hose configurations on the leg just for testing or is that a final configuration? I am very excited about your progress and can’t wait to see this beast in action.

    1. Good questions… These depend on a lot of factors, but the rough numbers we’re forecasting from simulation are ~35gpm for a tripod gait at 3.5 mph over flat ground (minimal leg lift… the higher you lift the legs the more flow you need).

      Within a gait cycle there are peak flows substantially higher than that, and lulls with much less flow, but we aim to catch most of that with an accumulator.

      The hydraulic power unit we built for the single leg should be able to supply 3gpm nominal.

  13. Swag arrived ! All the way down under to Sydney, Australia . Thanks team.
    Great to see progress on stompy . More updates please ! Technical engineering explanations of what you are doing and why are fantastic, but we all appreciate they take time to write.

    Perhaps one of you has a girlfriend studying arts or journalism…… who would just love to take over the blogging ? Just a thought !

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