Blaise,

 I tried to post this at the trac site. But I can't seem to login after registering. So I'm posting this here. Sorry everybody for the spam.

~Deepak

I tried playing around with the modified code. I can get ::open to work on the hokuyo port by setting the O_EXLOCK flag.  Also there are some other
settings that need to be changed with tcsetattr() and I've made those changes in the 
code below. 

 However, laserReadLine() hangs  when trying to read a line from the file. It seems
that fgets() doesn't  work on the usb in mac.  I tried using read() instead 
but that  reads a fixed amount of data  from the port and does not
stop on newline.

 Now I'm at a loss to proceed. Any ideas? I'm not much of a driver
hacker and don't really understand all the hokuyo code, so I'm not sure I can fix this myself.

What I have so far is attached.

~Deepak

Blaise Gassend <blaise@willowgarage.com>
Sent by: ros-users-bounces@code.ros.org
08/19/2010 12:40 AMPlease respond toros-users@code.ros.org

 To   ros-users@code.ros.org
 cc  
 bcc   Deepak Ramachandran/HRA/ASC/HONDA
 Subject   Re: [ros-users] hokuyo on mac
 

I have replied in the trac ticket:
https://code.ros.org/trac/ros-pkg/ticket/3826

Please try to post answers there. It makes the discussion easier to keep track of later.

The short of it is that I pushed a patch into trunk that looks more like Hokuyo's code, and I would be interested in having you give it a spin.

On Wed, Aug 18, 2010 at 8:14 PM,  <DRamachandran@hra.com> wrote:


Blaise,


   So I have a rudimentary version working now. I downloaded the hokuyo sample code from
here:

http://www.hokuyo-aut.jp/02sensor/07scanner/download/urg_programs_en/index.html

and adapted md_scan.c so that it outputs the data to a file which I then read from within a ros node.  Kind of hackish, but the problem was that the c++ version didn't compile on my machine (linker errors within SDL (?) ). 

I'm not sure if what I have is enough however. I guess the ros drivers do some postprocessing on the scan data before outputting, which I don't. I tried integrating with some odometry for my robot (which I know is fairly accurate) to do simple localization in AMCL and the particles jump all over the place and then the covariance blows up very fast to NaNs. Is this what you would expect with unfiltered laser data?

What should I do next? I can try integrating this code into the ROS hokuyo driver. It should be as simple as replacing the fopen with the setSerial code in the hokuyo sample code. I think that be best done by someone who knows what he is doing.

~Deepak  






No, I haven't worked on it more. Because the problem is happening on the
open command, it isn't even clear that the MacOS USB driver is doing the
right thing. If I were you I would look for success stories for USB
Hokuyos on MacOS. They might give some useful pointers.

On Wed, 2010-08-11 at 18:13 -0700, DRamachandran@hra.com wrote:
> Hi Blaise,
> 
> Sorry for the 8months (!!) gap in reply. I was distracted by other
> things and stopped working on this. 
> But now I'm planning to get back to working on this and I was
> wondering a solution has been found yet ?
> 
> cliff notes: Hokuyo not working on mac os x snow leopard, ros 1.0.0.
> fopen call on hokuyo tty hanging. reason unknown. last email of
> previous thread attached. 
> 


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