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Thread: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

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    Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    When I saw the HROS-5 and heard rumors about a smaller more affordable AX-12 based version I instantly knew I wanted one.

    The reality is, I wanted a Darwin-OP, but that was out of the question. The thing that I loved most about the Darwin-op was how it didn't take itself too seriously. The Darwin is a pretty impressive and capable robot, but it is also cute as hell.

    I run a FIRST Robotics team and robotics class at the high school where I work. One of the teams goals, and the focus of this year is inspiring others. We wanted to build a cute, fairly accessible robot that we could use at public functions in order to inspire others in engineering and robotics. It is also a dream of mine to at some point in the future field an autonomous humanoid robot soccer team. I don't have it in my school budget to afford one $12k robot let alone three, though perhaps I can swing $1600 :-)

    We decided to start by converting a bioloid comprehensive into an HROS-1, we also plan to purchase an HROS-1 kit in the future.

    I called over to Trossen to find out what the bottle necks would be in trying to do this. I was informed that in the future they plan to sell the arbotix pro as a stand alone, but they won't have any extra for a while. Converting a bioloid would require either an arbotix pro or a CM-730 from a Darwin-OP electronics kit. Oddly I just happened to have one of those. So off we went.

    We wanted to style the robot after the robot from Big Hero 6. We felt that it would be recognizable to a wide range of younger individuals and also seen as not threatening or scary. while we originally thought of designing the head along those lines we ended up going in a different direction with the head to account for the camera. We need to mount and wire a small fan to inflate the body and will probably have to sew in elastic to trap the air in order to get it to properly inflate.



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    The students assembled the robot and ID'd all of the servos. They started sewing the body together but ran out of time at the end of the school year. I finished that and printed a few different heads to try out over the break.

    I really want to see these guys run the Darwin-OP soccer ball chasing program in the near future. I think that would be a great way to demo robotics in an appealing way to young people. We also want to program it to tell jokes and play games.

    We ran into a few issues during this build. First off you need the Raspberry pi 2 model B for the software to work. Trying to run it on a regular raspberry pi 2 makes the whole operation incredibly unstable.

    Second, the CM-730 software is slightly different than that of the arbotix pro. I had to get help installing some changes run on the HROS-5 in order to get that to work.

    Finally, the arbotix pro has a 5 volt power out to run the Raspberry Pi. The CM-730 does not. We tried using a voltage regulator, but you really need to use a Higher amperage BEC or else the Raspberry Pi will brown out and crash.

    There were a few other issues, such as not having the same hole spacings on our brackets as on the real thing. All in all though the process was pretty painless.

    That said, I am not sure it is worth it or feasible for anyone else to do this and still meet the price point set by Trossen, even if you already own a bioloid.

    The weight difference between the metal and plastic brackets adds up, and the metal brackets are relatively expensive. Having them cut out by a place like big blue saw is even more expensive, and then you have to bend them yourself or pay to have them done.

    At the school we are set up to do laser cutting and 3D printing. It isn't that easy to do those things at home.

    Finally the CM-730 or Arbotix Pro are going to be hell to come by. Once the Arbotix pro is for sale my opinion on that may change.

    In any case, major thanks to the good people over at Trossen and Andrew for all of their help making this project a reality.

    DB

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    Quote Originally Posted by darkback2 View Post
    Converting a bioloid would require either an arbotix pro or a CM-730 from a Darwin-OP electronics kit. Oddly I just happened to have one of those. So off we went.
    Glad it finally found a use.

    Quote Originally Posted by darkback2 View Post
    I really want to see these guys run the Darwin-OP soccer ball chasing program in the near future. I think that would be a great way to demo robotics in an appealing way to young people. We also want to program it to tell jokes and play games.
    Need to add a tether for external power during long displays of the soccer demo, and keep a fan or CO2 duster handy for when the knees start overheating. Usually fun when it starts chasing kids' shoes/socks around a room because it only tracks by color.

    Quote Originally Posted by darkback2 View Post
    We ran into a few issues during this build. First off you need the Raspberry pi 2 model B for the software to work. Trying to run it on a regular raspberry pi 2 makes the whole operation incredibly unstable.
    I thought there was only one model of RPi2 (the RPi2 Model B) and five versions of the RPi1: Model A, Model B, Model A+, Model B+, and the compute module. IIRC, the RPi-B+ and RPi2-B have the exact same footprint, and they share the mounting holes and basic connector locations with the RPi-A+.

    Quote Originally Posted by darkback2 View Post
    Finally, the arbotix pro has a 5 volt power out to run the Raspberry Pi. The CM-730 does not. We tried using a voltage regulator, but you really need to use a Higher amperage BEC or else the Raspberry Pi will brown out and crash.
    The CM-730 has a 5V buck converter on board for DXL comms and feeding the 3.3V linear regulator for the STM32, but I'm thinking it can only put out about 500mA. The Arbotix-Pro uses the horizontal mounting Murata OKI-78SR in both 5V and 3.3V versions for 1.5A each at rather high efficiency. If you want overkill, you could go for the OKR-T/10-W12-C for up to 10A at 5V (through hole package with variable output voltage via resistor) from a ~12V input, or a Vicor PI3424 for up to 15A at 5V (fixed output voltage, but uses tiny 123-BLGA SMD package; Zero-Voltage Switching is so wonderful when well implemented) from an input up to 18V.


    Quote Originally Posted by darkback2 View Post
    Finally the CM-730 or Arbotix Pro are going to be hell to come by. Once the Arbotix pro is for sale my opinion on that may change.
    Supposedly they should be shipping the next batch of beta HROS-1 + Arbotix-Pro very soon, unless there was another big delay in manufacturing and/or testing of the newest Arbotix-Pro revision.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh
    more bleh

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    This is so cool. Does it have a name?

    I like the look of the nylon suit and the head model Really looking forward to seeing it when you get some air trapped inside!
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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    Cool project - Will be fun to see what you and the kids are able to do here!

    Kurt

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    So...Small hang up. I went with 1.4 watt fans. One wan't enough to inflate the suit, so I tried two.

    First test went great. I was able to keep the robot walking around for an entire battery. Then the robot started hanging up. It would take a few steps and then freeze.

    I am unsure as to the exact source of the problem, and having the entire robot covered in nylon isn't helping.

    I have the two fans drawing power from one of the unused dynamixel servo ports.

    So theorys are...
    1) drawing too much current through the port causing either some heat issues on the board
    2) drawing too much current causing a brown out of the board
    3) I have already damaged something.

    Running the robot without the fans seemed to work and stop the hang-ups. :-(

    DB

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    So...While lock-ups seem to happen more when the fans are running, I have gotten a lock up without the fans plugged in at all. Also, a draw of even 3 watts is nothing when compared with the draw of a stalled servo, so the ports should be fine handling the fans.

    So now I have to go over all of the wires to make sure nothing is pinched or anything. I am also wondering if the problem is related to the amount of time the robot is walking.

    DB

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    What exactly occurs during the hangups? Does the program on the RPi stall/crash? Does the PS3 controller disconnect? Do the servos just stop responding until a CM-730 reset then restarting the demo program on the RPi? Does the CM-730's FT233RL port suddenly disappear from the RPi's USB devices?

    We had repeated issues with the CM-730 + fit-pc2i-sbc refusing to successfully enumerate the FT232RL in one of the DARwIn-OP. It was almost certainly the fit-pc2i-sbc USB port/hardware as the issue occurred with multiple CM-730 (different revisions) on the same bot. Replacing the cables twice failed to resolve it, but it was an intermittent problem where it would connect fine many times then fail then maybe start working again on the next reboot. The CM-730 you have was never actually inside any of the DARwIn-OP and was only briefly used for testing servos with experimental code on my netbook or a lab pc, so I don't think it ever experienced the fail-to-enumerate error.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh
    more bleh

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    So to describe the "hang-ups" and a couple of other issues.

    I am running the Raspberry Pi2.

    I have it set up so that on bootup it runs the PS3 controller software. I have to be at work in order to connect to the raspberry pi remotely so I can't see what else might be going on.

    The robot will be walking and will just suddenly stop walking mid stride. Sometimes it comes back a few moments later and starts walking again, and other times it just stops (freezes) and doesn't move again until I power down and reboot. When it stops the servos have torque and hold their position.

    With the suit on I can't even see if there are any blinking lights suggesting the raspberry pi is still sending information.

    Thanks for the help

    DB

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    There are several possible causes that come to mind, but not sure which applies without more information.

    Are you using the crappy USB to 4-pin molex/dynamixel cable that I cobbled together, or the nicer USB to molex PCB from trossen with a stock 4-pin dynamixel cable? The crappy cable will probably not survive very much movement before the wires break at the molex connector because of crap wire, over-crimped pins, and no strain-relief.
    A bad USB cable could cause the FT232RL to disconnect and re-enumerate as a differently numbered '/dev/ttyUSBn' device if the demo program is still trying to access the original port/device (name/number cannot be reclaimed until released by demo program and then the FT232RL disconnected and reconnected). A bad cable might possibly be able to disconnect the FT232RL for a sufficiently short period of time that it briefly stops responding long enough to cause a short timeout error in the demo program without requiring it to re-enumerate and get a new '/dev/ttyUSBn' number/name.


    Not sure how the demo program is supposed to react to a lost connection to the PS3 controller, but maintaining the pose from 'last valid controller input' would probably be the safest. The fact that the servos do not lose power means it is unlikely to be a brown-out issue involving the CM-730, but whatever 5V regulator you are using for the RPi2 might be more sensitive to input voltage fluctuations and/or produces a generally unstable output voltage under variable loading.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh
    more bleh

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    Re: Semi-Scratch Built HROS1 Inspiratron (baymax vs .001)

    Quote Originally Posted by darkback2 View Post
    So...While lock-ups seem to happen more when the fans are running, I have gotten a lock up without the fans plugged in at all. Also, a draw of even 3 watts is nothing when compared with the draw of a stalled servo, so the ports should be fine handling the fans.
    I agree. On my hexapod I have 6x 1watt fans running off the 12V supplied on the dynamixel bus.

    Quote Originally Posted by darkback2 View Post
    The robot will be walking and will just suddenly stop walking mid stride. Sometimes it comes back a few moments later and starts walking again, and other times it just stops (freezes) and doesn't move again until I power down and reboot. When it stops the servos have torque and hold their position.
    From this description it does not sound like the pi is rebooting because you do not have to reconnect the PS3 controller to continue use.

    Oh there is a bug with PS3 demo where it uses 100% cpu due to a while loop with no delay in processing. Just before line 206 in ps3_demo/main.cpp add

    Code:
    usleep( 10000 );
    Hopefully that helps. The other thing I'm thinking it sounds like is a lack of comms between the RPi2 and the CM730.
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