[sudo-discuss] robot limitations and hacking

[johanna faust]

*not that this is my field or anything, but this thread was pretty
interesting, and poking around I found this:*

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The Fast Research Interface
for the KUKA Lightweight Robot

Günter Schreiber, Andreas Stemmer, and Rainer Bischoff


"Abstract—The KUKA lightweight robot (LWR) provides many unique features
for robotic researchers. To give full access to these features, a new
interface was developed that gives direct low-level real-time access to the
KUKA robot controller(KRC) at high rates of up to 1 kHz. On the other hand,
all industrial-strength features, like teaching, motion script features,
fieldbus I/O and safety are provided. Using standard UDP socket technology,
the user is not limited to one specific runtime system. This paper
describes the capabilities of the interface,the practical realization
within the LWR control architecture, and first applications of the
interface. "

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PDF here
<http://www.wies-pro.de/pages/publications/KUKA_FRI_from_WS_Proceedings_ICRA2010.pdf>
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*because i dearly love to find things sometimes*,
*especially if relevant*

On Tue, Sep 9, 2014 at 11:12 PM, Jake <jake at spaz.org> wrote:

> My friend Hao of Dorabot wrote me an email that clarifies what we can
> expect from the robot.  Of course this assumes no hacking, and we can hack.
>
> one thing I was interested in was "remote" mode through the serial port. I
> believe that it can be set to be controlled by commands like "let me send
> you this job" "start that job" which would allow us to effectively control
> it in real time.
>
> but that will take some reading of manuals and experimenting.  As for the
> latter, i have connected the robot's serial port to the desktop computer we
> use for 3d printing, and I can provide logins for that machine to anyone
> who wants to experiment.  I confirmed that with the null-modem adaptor
> (thanks Somebody!) it does communicate, although i haven't had any
> meaningful conversations with it.
>
> of course there is always the radical alternative - the entire YASNAC
> control system could be replaced with a homebrew solution that allows us to
> do whatever we want.  The problem is that it would take a bit of
> programming to drive the axes at speed without overshoot, and there's
> dynamic gravity and inertia dependant on the posture of the thing and the
> mass of whatever it's holding.. could be a lot of math to get it perfect.
>
> however, if someone were to create a control program for it, a lot of
> people around the world might like to use it.  Hell, people would probably
> pay for it since it would easily replace an entire YASNAC ERC unit.
>
> the motor controllers we have are the CACR series as described here:
> http://spaz.org/~jake/robot/CACR-SR-servopinouts.pdf
>
> and they are pretty simple to control - you send them an analog voltage to
> tell them which direction to turn, and how fast.  You send an analog
> voltage to say how much torque to exert (seperately for each direction),
> and it sends out analog voltages telling you how fast it is going, and how
> much torque it's exerting.  And of course the encoders are always telling
> you the actual position for all the axes so you can decide whether to make
> changes to get what you want.
>
> in the meantime though, we should keep playing with it as-is and see if we
> can "hack" to get control of it without anything as radical as a
> replacement controller.
>
> -jake
>
> ---------- Forwarded message ----------
>
> There are several models of MOTOMAN robot that can be controlled over
> serial port, and some even supported by ROS Industrial community. If your
> Robot controller is DX100, then you are very lucky.
>
> However I think your robot is super old so probably not supported by ROS
> Industrial. You can check it out here:
> http://wiki.ros.org/Industrial/supported_hardware
>
> Anyway, usually an industrial robot can be used in following ways:
> Teach & Replay by teach panel
> offline programming (generate a tool path offline and upload it, like 3D
> printer)
>
> modern robot can be used in these ways, in addition to previous ones:
> online program uploading (you generate end-effector/tool path and upload
> to the robot control box via serial port/ethernet, and the robot executed
> it right after it receives the path.
>
> very few robot support this: real-time control of the robot joint,
> including position, velocity, acceleration and so on. As far as I know,
> only Universal Robot and maybe Baxter support this. Kuka/DLR's LBR(Light
> Weight Robot) might support it too, but it's not for sale to general public.
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>
>


-- 
*Be seeing you.*
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